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Article

Screening of 258 Pesticide Residues in Silage Using Modified QuEChERS with Liquid- and Gas Chromatography-Quadrupole/Orbitrap Mass Spectrometry

by
Yujie Xie
1,
Xingqiang Wu
1,
Yanling Song
2,
Yini Sun
2,
Kaixuan Tong
1,
Xiaoxuan Yu
1,
Chunlin Fan
1 and
Hui Chen
1,*
1
Key Laboratory of Food Quality and Safety for State Market Regulation, Chinese Academy of Inspection & Quarantine, No. 11, Ronghua South Road, Beijing 100176, China
2
Laboratory of Heilongjiang Feihe Dairy Co., Ltd., Qiqihar 164800, China
*
Author to whom correspondence should be addressed.
Agriculture 2022, 12(8), 1231; https://doi.org/10.3390/agriculture12081231
Submission received: 9 July 2022 / Revised: 2 August 2022 / Accepted: 13 August 2022 / Published: 15 August 2022
(This article belongs to the Special Issue Screening and Risk Monitoring of Chemical Pollutants in Agricultural Products)
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Abstract

:
A method for the simultaneous screening of 258 pesticide residues in silage using modified QuEChERS combined with liquid chromatography (LC)- and gas chromatography (GC)- quadrupole-Orbitrap mass spectrometry (Q-Orbitrap/MS) has been developed. After hydration, the silage was homogenized with a 1% acetic acid–acetonitrile solution, and the extract was purified using C18, PSA, and anhydrous magnesium sulfate. Finally, the sample was detected using LC/GC-Q-Orbitrap/MS, and quantified using an external standard method. The results showed that 258 pesticides had an excellent linear relationship in the range of 0.1–50 μg L−1, and that the coefficients of determination (R2) were more than 0.99. The screening detection limit (SDL) of silage was in the range of 0.5–50 μg kg−1, and the limit of quantitation (LOQ) was in the range of 1–50 μg kg−1. The accuracy and precision of the method were verified at the spiked levels of 1-, 2- and 10-times LOQ, and the recovery of 258 pesticides was in the range of 66.5–119.8%, with relative standard deviations (RSDs) of less than 20% (n = 6). This method was simple, rapid, and reliable, and could be applied to screen and quantify multi-pesticide residues in silage.

1. Introduction

As a bulk livestock product, milk yield and quality is of widespread concern. “Grass-raising livestock” has been proven to be a reliable source of high-quality dairy products [1]. Silage is fermented from fresh plants as a necessary fundamental feed for dairy farmers [2], and its production process mainly includes the steps of harvesting, processing, transportation, filling, compaction, and capping [3,4,5]. As high-quality roughage, silage is rich in nutrients after 45 days of fermentation. It is an essential source of fermentable carbohydrates for ruminants, and is known as the “king of feed” [4,6,7]. The silage of interest in this study mainly uses corn stover as the raw material, which has high nutritional value and a wide market demand.
The demand for silage is growing with the rise of the livestock industry in China. To increase silage yield, the irrational application of pesticides may exist during maize cultivation [8]. Pesticide residues in silage are mainly derived from pesticide spraying during planting to prevent diseases and pests [9]. According to the literature, the main pesticides involved in maize cultivation are organophosphorus, organochlorine, and carbamate [10,11]. In addition to the incorrect use of pesticides, pollution in the environment can also cause silage to contain a small number of pesticide residues, such as water and soil that is contaminated by pesticides [12,13]. At the same time, the farmer sprays the pesticide to kill insects and bacteria before silage fermentation. Once an application is deemed unreasonable, it will result in residues, compromising the quality and safety of silage [14]. When contaminated silage is fed to cows, pesticides accumulate in their bodies and are transferred to the milk during lactation, which can harm milk quality [15]. The quality of silage has been the primary focus of safety supervision, but the silage contains numerous impurities (e.g., pigments, sugars, fatty acids, and proteins) that make pesticide residue identification difficult [15]. Therefore, it is necessary to figure out how to efficiently eliminate matrix background interference and to develop a method for screening pesticide residues in silage.
Solid-phase extraction (SPE) [16] and QuEChERS [17] were the most common forage pretreatment methods. The QuEChERS method is easy to use, requires fewer reagents, and is quick to process. It meets the requirements of green chemistry and is receiving increasing attention. However, the pretreatment methods of hundreds of pesticide residues in silage have not been reported. Viera et al. [18] detected 72 pesticide residues in 10 agricultural items (including corn silage) using QuEChERS with liquid chromatography-tandem mass spectrometry (LC-MS/MS). The limit of detection of this method was from 4.8 µg kg−1 to 48 µg kg−1. The recovery was in the range of 70–120%. The literature research shows that the current published QuEChERS method has achieved satisfactory stability and recovery, but the number of pesticides detected and the sensitivity of the method need to be improved. It is vital to apply sensitive and reliable techniques to detect pesticide residues in forage. The current analytical methods for the detection of multi-pesticide residues are mainly GC-MS [19], GC-MS/MS [19,20], and LC-MS/MS [19,21]. These chromatography-mass spectrometry techniques have become an essential analytical tool. Still, they suffer from a lack of sensitivity, low resolution, and the inability to avoid false positives [22]. High-resolution mass spectrometry (HRMS), such as electrostatic field Orbitrap MS, has been widely used in food analysis due to its high mass accuracy at the ppm level, ultra-high resolution, and accurate mass information, enabling high-throughput information acquisition and retrospective analysis without additional injection [23,24,25].
This work aims to screen multi-pesticide residues that may have remained from planting to fermentation, based on the QuEChERS with LC/GC-Q-Orbitrap/MS method. This work is the first reported to screen and quantify compounds in silage using the HRMS methods. Because of the difficulties encountered during pretreatment, several typical cases, such as the hydration volume, extraction volume, salting-out agent type, and purification filler, were optimized to minimize the matrix effects and to improve recovery. The samples were detected using LC/GC-Q-Orbitrap/MS to achieve sensitivity for pesticides with different physico-chemical properties. A methodological validation was carried out, and the qualitative and quantitative analysis of various pesticide residues in forage was successfully completed. Additionally, the validated method was applied to the actual silage samples.

2. Materials and Methods

2.1. Instrumentation

The ultra-high-performance liquid chromatography quadrupole Orbitrap mass spectrometry system used was the Ultimate 3000 UHPLC system (Dionex Corporation, Sunnyvale, CA, USA), in conjunction with the Q-Orbitrap mass spectrometer from Thermo Fisher Scientific (Bremen, Germany). A Trace 1310 GC coupled to a quadrupole Orbitrap mass spectrometry with a TriPlus RSH automatic sampler was purchased from Thermo Fisher Scientific (Bremen, Germany). A PL602-L electronic balance was purchased from Mettler-Toledo (Zurich, Switzerland); an AH-30 Fully Automatic Homogenizer was obtained from Raykol Instrument Co., Ltd. (Xiamen, China); an N-112 Nitrogen evaporator concentrator was obtained from Organomation Associates (EVAP 112, Worcester, Massachusetts, USA); as well as an SR-2DS oscillator (Taitec, Japan), a KDC-40 low-speed centrifuge (Zonkia, China), and a Milli-Q ultrapure water machine from Millipore Corporation (Milford, MA, USA).

2.1.1. Chromatographic and MS Conditions of LC-Q-Orbitrap/MS

Chromatographic Conditions: Chromatographic separation was achieved under chromatographic conditions: a reversed-phase chromatography column (Accucore aQ 150 × 2.1 mm, 2.6 μm; Thermo Fisher Scientific, Santa Clara, CA, USA); mobile phase A is 5 mM ammonium acetate–0.1% formic acid–water; mobile phase B is 0.1% formic acid–methanol; gradient elution program, 0 min: 1% B, 3 min: 30% B, 6 min: 40% B, 9 min: 40% B, 15 min: 60% B, 19 min: 90% B, 23 min: 90% B, 23.01 min: 1% B, and run after 4 min; the flow rate is 0.4 mL min−1; column temperature: 40 °C; injection volume: 5 µL.
MS Conditions: An HESI-II electrospray source was used on the Q-Orbitrap in positive ionization mode. The conditions for electrospray ionization were set as follows: scan mode: full MS/dd-MS2 (full scan/data dependent secondary scan); full MS scan range: 80–1100 m/z; resolution: 70,000 FHWM, full MS; 17,500 FHWM, MS2; maximum injection time: full MS, 200 ms; MS2, 60 ms; automatic gain control: full MS, 1 × 106; MS2, 2 × 105; loop count: 1; multiplex count: 1; isolation width: 2.0 m/z; under fill ratio: 1%; stepped normalized collision energy: 20, 40, 60; apex trigger: 2–6 s; dynamic exclusion: 8 s.

2.1.2. Chromatographic and MS Conditions of GC-Q-Orbitrap/MS

Chromatographic Conditions: Chromatographic separation was achieved under chromatographic conditions: TG-5 SILMS chromatography column (TG-5 SILMS 30 m × 0.25 mm (i.d.) × 0.25 µm); gas chromatographic heating procedure: 40 °C for 1 min, 30 °C min−1 to 130 °C, 5 °C min−1 to 250 °C, 10 °C min−1 to 300 °C, 7 min; injector type and temperature: SSL, 250 °C; injection volume: 1 µL; carrier gas: helium; flow rate: 1.2 mL min−1.
MS Conditions: Ion source: EI source; electron energy: 70 eV; ion source temperature: 280 °C; mass spectrum end transmission line temperature: 280 °C; solvent delay time: 4 min; scan range: 50–600 (m/z); resolution: 60,000 FHWM (200 m/z); automatic gain control: 1 × 106; scan mode: full scan.
The mass spectrum information for 258 pesticides is shown in Table 1.

2.2. Reagents and Materials

Silage samples were collected from local dairy farms and consisted of corn stover (Inner Mongolia; Shaanxi; Hebei; Heilongjiang; Shandong Province, China). All pesticide standards (purity grade, >98%) were obtained from Alta Company (Tianjin, China); formic acid, ammonium acetate, acetonitrile, methanol (all LC-MS grade), and ethyl acetate (HPLC grade) were obtained from Fisher Scientific Co. (Cranbury, NJ, USA); analytical grade forms of acetic acid, sodium chloride, anhydrous Na2SO4, trisodium citrate, disodium citrate, and anhydrous MgSO4 were obtained from Shanghai Anpu Experimental Technology (Shanghai, China). The clean-up absorbents as octadecylsilane (C18) and primary secondary amine (PSA) were obtained from Tianjin Agela Technology (Tianjin, China).

2.3. Preparation of Standard Solutions

The purchased standard solution should be stored at −18 °C or 4 °C under dark conditions. When mixing the standard configuration, a 10 μg mL−1 group of mixed standards should be prepared according to different categories, then diluted to a concentration of 1 μg mL−1 for the large group mixed standard. The standard should be stored at 4 °C under dark conditions for one month.

2.4. Sample Preparation

2.4.1. Extraction

A sample of 2.0 g silage was weighed into a 50 mL tube. A 2 mL volume of water was added, and then 20 mL of 1% acetic acid acetonitrile (v/v) was added and homogenized at 12,000 rpm for 2 min. After that, EN salt (4 g MgSO4, 1 g NaCl, 0.5 g disodium citrate, and 1 g trisodium citrate) was added. The tube was shaken for 10 min, followed by centrifugation for 5 min at 4500 r min−1.

2.4.2. Clean-up

Five milliliters of supernatant was pipetted into a 15 mL clean-up tube (containing 500 mg MgSO4, 30 mg PSA, and 50 mg C18). The clean-up tube was shaken for 10 min, followed by centrifugation at 4200 rpm for 5 min. Subsequently, 2 mL of the supernatant from the clean-up tube was pipetted into a 10 mL glass tube and evaporated to dryness in a 40 °C water bath with a gentle stream of nitrogen. Finally, 1 mL of acetonitrile/water (3:2, v/v) solution was used to re-dissolve the solution and pass it over the membrane for UHPLC-Q-Orbitrap/MS analysis, or 1 mL of ethyl acetate was used to re-dissolve the solution and pass it over the membrane for GC-Q-Orbitrap/MS analysis. The flow chart of the silage sample analysis program is shown in Figure 1.

2.5. Validation of the Method

The method was validated in the silage matrix by evaluating the following parameters: matrix effect, linearity, screening detection limit (SDL), the limit of quantification (LOQ), recovery, and precision. To define the SDL, according to SANTE/11312/2021 [26], this was the lowest level at which pesticide had been screened in at least 95% of the samples. Calibration curves were investigated by determining the results of a series of standard addition recovery experiments (1, 2, 5, 10, 20, 50, 100, 200, 300, and 500 μg kg−1) of blank matrix extract solutions before injection. Matrix effects were calculated using the following formula: matrix effect (ME, %) = [(slope of matrix matching standard curve—the slope of solvent standard curve)/slope of solvent standard curve] × 100. To validate the accuracy and precision of the established method, recovery was performed for each compound in six replicates for three spiked levels at 1-, 2-, and 10 times the LOQ.
Thermo Fisher Scientific TM Tracefinder TM (version 4.1) software was used to analyze the data based on the self-built database. To ensure the accuracy of target compounds identification, the specific settings of the corresponding screening parameters included the retention time offset threshold (≤0.15 min) and mass deviation (≤5 ppm). The data results were analyzed using Excel (Version 2016) software, and an analysis of graphs was drawn using Origin 2018 software.

3. Results and Discussion

3.1. Sample Extraction and Clean-Up

Considering silage’s high pigment and fiber-rich characteristics, the sample weight should be appropriately reduced when using QuEChERS for pretreatment. Combined with the research of the previous group on forage matrix pretreatment [27], the sample weight was fully considered for instrument detection sensitivity and matrix interference, and so 2 g of substance was selected for further research in this work. The QuEChERS procedure was evaluated due to the potential for matrix interference, one of the most challenging situations in high-throughput screening, and essential for validating quantitative determination. Therefore, different parameters based on the QuEChERS method have been evaluated.

3.1.1. Optimization of Extraction Solvent Volume

During the pretreatment process, the extraction solution significantly influences the extraction efficiency of the method. According to the reported literature, acidified acetonitrile was chosen as the extraction solution for pesticide residue detection from relatively simple matrices such as fruits and vegetables, to complex matrices such as tea and wolfberries [28,29]. Therefore, 1% acetate acetonitrile (v/v) was chosen as the extraction solution, and the volume was optimized.
The volume of the extraction solution affects the extraction efficiency of the target compounds and the strength of the matrix background. This paper optimized the extraction solution volumes of 10 mL, 20 mL, and 40 mL. As shown in Figure 2, when the extract volume is 10 mL, the percentage of pesticides that can be screened out of the total pesticides was 92.8%, while the percentages for 20 mL and 40 mL were 91.5% and 89.3%, respectively. There was no significant difference between 10 mL and 20 mL. On the other hand, considering the number of compounds that met the recovery criteria (REC: 70–120%, RSD ≤ 20%), 88.6% of the compounds satisfying the recovery criteria were effectively extracted under 20 mL. In comparison, the percentages for 10 mL and 40 mL were 87.0% and 83.7%, respectively. The results showed differences in pesticides meeting the recovery in silage with different extraction solution volumes. As the extraction volume increased, the sample matrix interference weakened, but the instrument detection sensitivity decreased. Therefore, using 20 mL of 1% acetate acetonitrile as the extraction solution could improve the screening capability and extraction efficiency of the target compounds. The volume of extraction solution was eventually chosen to be 20 mL.

3.1.2. Optimization of Hydration Volume

Silage has a high fiber content and a low water content (<70%). Homogenizing the extraction without water will lead to uneven samples and will affect the extraction efficiency of the target compounds [30]. Under a spiking level of 100 μg kg−1, this work investigated hydration volumes of 0 mL, 2 mL, and 3 mL. The optimal conditions were selected according to the percentage of recoveries of target compounds in silage. As shown in Figure 3, 90% of the target compounds could be screened out if the extraction was carried out without water. While there were relatively few compounds that met the hydration recovery criteria, the percentage of quantification was 93%. The above results indicate that the target compounds could not be effectively transferred from the matrix to the extraction solution. Therefore, water was added to the sample for hydration before extraction, to improve sample dispersion and to increase solute transfer efficiency. When the hydration volume was 2 mL or 3 mL, the screening rate of pesticides was 97.7%, and the quantification was 95.3% and 94.6%, respectively. Both the screening and the quantification were higher than those without hydration.
In contrast, hydration significantly improved the extraction efficiency of some organonitrogen pesticides (containing nitro functional groups or triazine ring compounds). Ethalfluralin, for example, has a dinitro functional group, which is a conjugated system with a unique bond between the single and double bonds. It can form O-H-O hydrogen bonds with water molecules, and its coordination number varies depending on the spatial configuration, exhibiting a certain degree of hydrophilicity. Its hydrophilic functional group forms a solvent shell around the compound as the number of water molecules increases, thus increasing the extraction efficiency of the compound during the subsequent extraction [31]. The results found that the recovery of ethalfluralin was less than 60% when unhydrated, and this increased to 119.8% and 108.4% with 2 mL and 3 mL of water, respectively. Terbutamol was not screened when it was not hydrated. After hydration, it cannot only be screened, but the recovery can be increased to 93.9% and 92.0%, respectively. Although hydration can improve the screening of some compounds, the amount of added water should not be excessive. Otherwise, this will increase the amount of anhydrous magnesium sulfate, which can affect some heat-, acid-, and base-sensitive pesticides. As a result, 2 mL of water for hydration was selected for further research.

3.1.3. Optimization of the Type of Extraction Salt

This work compared the effects of several extraction salts to make the target compounds easier to extract. The extraction salts contain AOAC with sodium acetate (6 g anhydrous MgSO4 and 1.5 g sodium acetate), EN with citrate as a buffer salt (0.5 g disodium hydrogen citrate, 1 g sodium citrate, 4 g anhydrous MgSO4, and 1 g sodium chloride), and traditional QuEChERS with sodium chloride (4 g anhydrous MgSO4 and 1 g sodium chloride) [32]. There was no significant difference in the number of pesticides that the three salting agents could screen at a spiked level of 100 μg kg−1. However, the recovery of carbamate pesticides (e.g., pirimicarb) is significantly higher with EN salts than with the other two extraction salts. The result indicated that the recoveries of some acid- and base- sensitive compounds are more stable under the buffer salt system. Otherwise, this work also compared the responses of compounds after using different extraction salts. Certain compounds have reduced responses after utilizing AOAC, whereas the responses of compounds using EN and QuEChERS increased. As shown in Figure 4A, the response changes of dichlofluanid and desmetryn were EN > QuEChERS > AOAC and EN > AOAC > QuEChERS, respectively. Therefore, EN was chosen as an extraction salt to extract the target compounds more effectively.

3.1.4. Optimization of the Adsorbent

Silage is mainly formed by fermenting fresh straw, and it contains a large amount of crude fiber, crude protein, organic acids, etc. It is dark in color and has a high pigment content. To effectively reduce the influence of interferents and pigments on the target compounds, different purification fillers, including anhydrous MgSO4, PSA, C18, and GCB were commonly applied to the purification. Anhydrous MgSO4 is used to remove residual water in the extraction. PSA could eliminate the interference of organic acids and pigments. C18 has a strong adsorption capacity and can be used to remove non-polar impurities such as lipids. GCB is used to remove pigments from the extraction [32]. Anhydrous MgSO4 and PSA were chosen as the main clean-up adsorbents, as the samples contained a large amount of organic acid and had been hydrated during the pretreatment process. Otherwise, considering other interferences in silage, C18 and GCB were also introduced. The following experimental conditions were compared: (1) anhydrous MgSO4 + PSA + C18 + GCB, (2) anhydrous MgSO4 + PSA + C18, and (3) anhydrous MgSO4 + PSA + GCB. The comparison shows that although GCB is effective in removing pigments, the use of GCB reduces the number of pesticides screened and the recovery of some compounds, especially planar compounds. For example, the recovery rate for thiabendazole using GCB is 49.5–59.1%, while the recovery increased to 83.5% without GCB. As shown in Figure 4B, 98.1% of compounds could be screened without GCB, of which 95.7% could be quantified for target compounds. In contrast, the screening capacity decreased to 97.7% and 96.9%, and the quantification capacity decreased to 94.6% and 93.0% with GCB. Therefore, anhydrous MgSO4 + PSA + C18 was selected for the purification step.
This work optimized the dosages of PSA and C18 to remove interfering substances from the silage effectively. To eliminate residual water, 500 mg anhydrous MgSO4 was applied. The dosage of C18 and PSA had little effect on the screening capacity, but had a more significant impact on the recovery of some compounds. For EPTC, fenamiphos, pretilachlor, and thiobencarb, the dosage of C18 significantly affects the recovery. As shown in Figure 4C, the recoveries of the four compounds range over 68.2–92.7%, 81.1–194.3%, 84.3–131.5%, and 67.4–183%, respectively, and the dosages of C18 were optimized as 30 mg, 50 mg, and 80 mg. As shown in Figure 4D, the dosage of PSA has a more significant impact on the organic nitrogen compounds, such as ethalfluralin, hexythiazox, and terbumeton. Hexythiazox and terbumeton were not screened out when the dosage was 30 mg, and the recovery of ethalfluralin was 64.6%. The recoveries of ethalfluralin, hexythiazox, and terbumeton ranged from 93% to 100.1% at 50 mg, while tebutone was not detected at 80 mg. The study selected 500 mg anhydrous MgSO4, 30 mg C18, and 50 mg PSA for further research.

3.1.5. Optimization of Purification Volume

The volume for purification is also one of the factors affecting the responses of target compounds. The interferents have a more significant effect on the target compounds as the volume for purification increases, and conversely, the interference effect is smaller. However, a small purification volume will result in lower mass spectrometry detection concentrations, reducing the sensitivity for some compounds. Different purification volumes of 3 mL, 5 mL, and 10 mL were optimized. By comparison, the lower volume significantly reduced the recovery of compounds. As Figure 5 shows, for buprofezin, when the volume for purification increases, the recovery increases from 60.6% to 73.9%, while phorate and terbufos increase from 54.9% to 79.6%, and from 53.4% to 79.2%, respectively. However, the target pesticides were affected by interferents with a lower response as the volume for purification increased. In the case of organic nitrogen compounds (such as fluazifop-butyl and buprofezin), the highest response of buprofezin was achieved at a purification volume of 5 mL, and the response was essentially the same at 3 mL and 10 mL. For fluazifop-butyl, the response decreased when the purification volume increased. The purification volume selected was 5 mL, to reduce the influence of interferents on compounds, and to improve the recovery of compounds.

3.2. Matrix Effect

The matrix effect was measured by comparing the slopes of the two standard curves, which were 1, 2, 5, 10, 20, 50, 100, 200, 300, and 500 μg kg−1 for the matrix standard curve and the solvent standard curve. The matrix effect in silage was calculated using the following formula: matrix effect (ME, %) = [(slope of matrix matching standard curve—the slope of solvent standard curve)/slope of solvent standard curve] × 100. Matrix effects can be classified into three categories based on the results of the calculated data:
  • |ME|, lower than 20% shows a weak matrix effect;
  • |ME|, between 20% and 50% shows a medium matrix effect;
  • |ME|, higher than 50% shows a strong matrix effect.
As shown in Figure 6, 27.1% of the compounds showed a weak matrix effect, 52% showed a medium matrix effect, and 20.9% showed a strong matrix effect. As a result, the matrix-matched calibration standard was used for quantitative analysis to reduce the matrix effect.

3.3. Method Validation

3.3.1. Linear Range, SDL, and LOQ

The mixed standard working solution of different concentrations was added into the blank silage sample, the sample was extracted and purified according to 2.4, and the matrix matching standard curve was established. High-resolution mass spectrometry (HRMS) was used to identify the target compounds. The ordinate of the standard curve was the peak area of the quantitative ions of each compound, and the abscissa was the matching mass concentration. There was good linearity in the range of 0.1–50 μg L−1, and the coefficients of determination (R2) were higher than 0.99 for 258 compounds in different linear ranges (see Table 1).
According to SANTE/12682/2021 [26], the method’s sensitivity was assessed using SDL. SDLs were determined by spiking a series of mixed standard solutions in 20 blank samples, and using the lowest level at which pesticides were screened in at least 95% of the samples. As shown in Table 1, the percentage of pesticides with SDLs of less than 10 μg kg−1 was 82.9%, indicating that the method has high sensitivity.
LOQs were determined as the lowest validated spike level, based on the recovery results by spiking a series of mixed standard solutions in blank samples. For silage, the LOQs were 1–50 μg kg−1, with 209 compounds that were less than or equal to 10 μg kg−1, as shown in Table 1. The method was proven to have a high sensitivity, and it could be routinely used for high-throughput screening and the quantitative analysis of multi-pesticide residues in silage at low concentration.

3.3.2. Recovery and Precision

This work evaluated accuracy and precision at three spiked levels. LOQs mixed standard working solution at 1-, 2-, and 10 times were used as the spiked levels, extraction and purification were performed according to Section 2.4, and six replicates were determined for each spiked level. The blank was run simultaneously, and the recovery and RSD were calculated after deducting the background. The method results are shown in Table 1. The recoveries of 258 pesticides in silage at three spiked levels were 66.5–119.7%, 71.5–117.6%, and 71.0–119.8%, respectively, with RSD being in the range of 0.93–20%, 0.88–14%, and 1.4–19%, respectively. This shows that the accuracy and precision of the method met the criteria of accurate quantification.

3.4. Comparison of LC/GC-Q-Orbitrap/MS

LC-Q-Orbitrap/MS and GC-Q-Orbitrap/MS were used to analyze the extracts of the same silage, to identify 258 pesticide residues (including 143 pesticides identified via LC or GC, 63 pesticides detected via GC, and 52 pesticides detected via LC). Because of the differences in the physico-chemical characteristics of some compounds, the monitoring could only be performed with one type of instrument. Neonicotinoid insecticides, for example, can only be identified using LC-Q-Orbitrap/MS. Nevertheless, some organochlorine pesticides can only be detected with high sensitivity via GC-Q-Orbitrap/MS. On the other hand, although some compounds were established using both LC-Q-Orbitrap/MS and GC-Q-Orbitrap/MS, there was a significant difference in detection sensitivity in the actual detection. For example, some polar pesticides were identified via GC-Q-Orbitrap/MS, but the SDL was so high that it was impossible to apply to sample detection. Some organophosphorus and pyrethroid insecticides such as fenthion, isocarbophos, fenpropathrin, and flucythrinate were often detected via GC-, which had a better detection sensitivity than LC-. However, GC- has been more widely used than LC- in traditional pesticide residue analysis methods. Some organophosphorus and pyrethroid insecticides (e.g., fenthion, isocarbophos, fenpropathrin, and flucythrinate) had a better detection sensitivity when using GC, than LC. The combination of the two techniques increased the detection capacity by 124.3% (GC-Q-Orbitrap/MS, 115 species) and 80.4% (LC-Q-Orbitrap/MS, 143 species) compared to the single technology. The percentage of pesticides with SDLs of less than 10 μg kg−1 was 82.9% when the two technologies were combined, meeting the supervision requirement for silage safety.

3.5. Analysis of Real Samples

The validated method was applied to screen and quantify pesticides in 37 silages from different provinces and farms. According to the test results, pyraclostrobin was found in one batch of silage, with a content of 3.2 μg kg−1, as shown in Figure 7. The actual sample testing showed a low risk of pesticide residue contamination in the silage. At the same time, pyraclostrobin residues in silage may be caused by the control of fungal diseases during corn planting.

4. Conclusions

This work differs from conventional detection methods, as it focuses on the screening and quantitation of compounds in silage, based on QuEChERS with LC/GC-Q-Orbitrap/MS. A rapid screening and quantification method of 258 pesticides in silage was established. Combining the two HRMS technologies allowed for the detection of several pesticide residues in silage with excellent sensitivity. The SDLs of pesticides that LC-Q-Orbitrap/MS or GC-Q-Orbitrap/MS may detect at less than 5 μg kg−1 accounted for 51.7 and 73.9% of the total, respectively. The method was applied to the rapid screening of 37 batches of silage from different farms. Pyaclostrobin was discovered in one of the silage samples. The technique was simple, quick, and sensitive. It could be used to screen and quantify several pesticide residues in forage represented by silage, according to the validation of the methodology and the determination of actual samples.

Author Contributions

Conceptualization, Y.X.; Data curation, Y.S. (Yanling Song); Funding acquisition, C.F.; Methodology, X.W.; Project administration, H.C.; Resources, Y.S. (Yini Sun); Software, K.T. and X.Y.; Validation, X.W.; Writing—original draft, Y.X.; Writing—review & editing, H.C. All authors have read and agreed to the published version of the manuscript.

Funding

This work was financially supported by the science and technology project of the State Administration for Market Regulation (2021MK165).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable.

Conflicts of Interest

The authors declare no conflict of interest.

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Agriculture 12 01231 g001 550
Figure 1. Flow chart of silage analysis program.
Figure 1. Flow chart of silage analysis program.
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Agriculture 12 01231 g002 550
Figure 2. The effect of extract volume on compounds.
Figure 2. The effect of extract volume on compounds.
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Figure 3. The effects of different hydration volumes on 258 compounds in silage.
Figure 3. The effects of different hydration volumes on 258 compounds in silage.
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Agriculture 12 01231 g004 550
Figure 4. The effects of salting-out agent and purifying agent on compounds. (A): The effects of salting-out on the response of compounds Dichlofluanid and Desmetryn; (1): AOAC, (2): EN, (3): QuEChERs; (B): The effect of purifiers on screening; (C): The effect of C18 on recovery; (D): The effect of PSA on recovery.
Figure 4. The effects of salting-out agent and purifying agent on compounds. (A): The effects of salting-out on the response of compounds Dichlofluanid and Desmetryn; (1): AOAC, (2): EN, (3): QuEChERs; (B): The effect of purifiers on screening; (C): The effect of C18 on recovery; (D): The effect of PSA on recovery.
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Agriculture 12 01231 g005 550
Figure 5. The effect of purification volume on recovery of compounds.
Figure 5. The effect of purification volume on recovery of compounds.
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Agriculture 12 01231 g006 550
Figure 6. Matrix effect distribution of 258 compounds.
Figure 6. Matrix effect distribution of 258 compounds.
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Agriculture 12 01231 g007 550
Figure 7. Chromatographic and mass spectra of pyraclostrobin in real samples.
Figure 7. Chromatographic and mass spectra of pyraclostrobin in real samples.
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Table
Table 1. HRMS parameters and validation parameters for all target analytes in silage.
Table 1. HRMS parameters and validation parameters for all target analytes in silage.
No.CompoundCategoryRT/MinMS1 ion (m/z)MS2 ion (m/z)R2SDL
(µg kg−1)		LOQ
(µg kg−1)		1-LOQ2-LOQ10-LOQInstrumentation
REC/%RSD/%REC/%RSD/%REC/%RSD/%
11-(2-chloro-4-(4-chlorophenoxy)phenyl)-2-(1H-1,2,4-triazol-1-yl)ethanolFungicides17.45350.0453118.04120.9994505085.76.788.16.286.21LC-Q-Orbitrap/MS
21-(2-Chloro-pyridin-5-yl-methyl)-2-imino-imidazolidine hydrochlorideInsecticides3.03211.0744126.01050.9983101085.55.390.47.787.56LC-Q-Orbitrap/MS
31-methyl-3-(tetrahydro-3-furylmethyl) ureaInsecticides2.8159.1127102.09140.9995202087.86.883.11.983.43LC-Q-Orbitrap/MS
42,4-D butylateHerbicides17.03185186.9970.99912271.28.7104.76.485.35GC-Q-Orbitrap/MS
52,4′-DDDInsecticides22.62235.0076165.06990.99952590.79.297.72.197.82GC-Q-Orbitrap/MS
62,4′-DDEInsecticides21.17245.9999176.0620.99911199.29.1816.5100.92GC-Q-Orbitrap/MS
73-(Trifluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide/3.37194.0536134.03490.99865595.2696.55.797.62LC-Q-Orbitrap/MS
84,4′-DDDInsecticides23.91235.0077165.06990.9991287.51089.16.588.22GC-Q-Orbitrap/MS
95-hydroxy ImidaclopridInsecticides4.02272.0541225.05390.9988505086.15.188.34.475.44LC-Q-Orbitrap/MS
10AcetamipridInsecticides5.46223.0744126.01060.99995599.33.894.34.279.15LC-Q-Orbitrap/MS
11Acetamiprid-N-desmethylInsecticides5.17209.059126.01050.99975594.77.7976.2813LC-Q-Orbitrap/MS
12AcetochlorHerbicides16.9146.0965162.09140.999625106.74.486.66.594.23GC-Q-Orbitrap/MS
13AcrinathrinInsecticides29.35181.0647180.0810.99955896996.399.75GC-Q-Orbitrap/MS
14AlachlorHerbicides17.22188.107146.09650.99965598.28.2113.53.495.12GC-Q-Orbitrap/MS
15Aldicarb-sulfoneInsecticides3.44240.10186.060020.9997505093.54.294477.93LC-Q-Orbitrap/MS
16AllethrinInsecticides19.33303.195135.08050.9994101095.8692.46.494.98LC-Q-Orbitrap/MS
17AllidochlorHerbicides6.9174.067898.096440.99980.51102.15.6102.54.499.84LC-Q-Orbitrap/MS
18alpha-HCHInsecticides13.53180.9373218.9110.999651096.44.489.72.3109.112GC-Q-Orbitrap/MS
19AmetrynHerbicides17.72227.1199170.04930.998355100.71.998.41.384.54GC-Q-Orbitrap/MS
20AtrazineHerbicides11.73216.101174.05430.999622107.812.8107.33.786.62LC-Q-Orbitrap/MS
21AzoxystrobinFungicides15.39404.1237344.10310.999655101.83.393.63.889.67LC-Q-Orbitrap/MS
22BenalaxylFungicides18.04326.1747148.11220.99982298.25.198.73.194.94LC-Q-Orbitrap/MS
23BendiocarbInsecticides8.38224.0914109.02850.99981010104.37.390.14.896.33LC-Q-Orbitrap/MS
24BenfluralinHerbicides13292.0541276.05890.99791010101.31496.59117.114GC-Q-Orbitrap/MS
25BenoxacorHerbicides13.66260.0236149.08360.9998202089.54.389.73.194.36LC-Q-Orbitrap/MS
26Benzovindiflupyr/32.37159.0365238.97150.99965593.65.2103.13.391.77GC-Q-Orbitrap/MS
27beta-HCHInsecticides14.52180.9371218.9110.99751010108.84.993.15113.311GC-Q-Orbitrap/MS
28BifenoxHerbicides27.67340.985173.01540.9991202084.617.893.612.992.61GC-Q-Orbitrap/MS
29BifenthrinInsecticides27.12181.1011166.07760.999722103.912.8935.386.34GC-Q-Orbitrap/MS
30BitertanolFungicides30.1170.0726141.06990.998722103.110.2845.4876GC-Q-Orbitrap/MS
31BoscalidFungicides31.51139.9898111.99490.99965594.38.8104.42.2932GC-Q-Orbitrap/MS
32BromobutideHerbicides16.96312.0951119.08570.9993202090.86.392.93.594.15LC-Q-Orbitrap/MS
33Bromophos-methylInsecticides19.46328.8798332.87460.999855105.49.2113.25.9102.72GC-Q-Orbitrap/MS
34BromopropylateInsecticides27.1182.944340.89930.99982587.93.797.32.5952GC-Q-Orbitrap/MS
35BupirimateFungicides17317.1636108.01140.999722101.2596.42.988.54LC-Q-Orbitrap/MS
36BuprofezinInsecticides18.93306.1629106.06520.99962297.95.399.42.995.95LC-Q-Orbitrap/MS
37ButachlorHerbicides21.44176.107188.1070.99975590.72.899.82.397.13GC-Q-Orbitrap/MS
38ButamifosHerbicides18.33333.102895.966760.99971010102.314.796.57934LC-Q-Orbitrap/MS
39ButylateHerbicides18.99218.157156.13850.99951273.115.575.39.481.46LC-Q-Orbitrap/MS
40CadusafosInsecticides18.61271.0946158.96990.99992290.79.8114.911.494.411LC-Q-Orbitrap/MS
41CarbarylInsecticides17.38144.057116.06210.99982270.211.31005.391.44GC-Q-Orbitrap/MS
42CarbendazimFungicides4.04192.0767160.05060.99935597.63.395.74.3108.98LC-Q-Orbitrap/MS
43CarbofuranInsecticides8.47222.1122123.04410.99891194.37.688.51185.54LC-Q-Orbitrap/MS
44Carbofuran-3-hydroxyInsecticides4.94238.107163.07520.99730.51095.10.9100.52.499.64LC-Q-Orbitrap/MS
45Carfentrazone-ethylHerbicides17.69429.07345.99570.9984101095.16.992.9999.66LC-Q-Orbitrap/MS
46ChlorantraniliproleInsecticides14.15481.9779283.92210.9996505082.75.394.37.680.14LC-Q-Orbitrap/MS
47ChlorfenapyrInsecticides23.06247.0479363.94090.9988505094.313104.712.289.62GC-Q-Orbitrap/MS
48ChlorfenvinphosInsecticides20.37266.9379323.00020.99985592.39.694.52.896.39GC-Q-Orbitrap/MS
49ChloridazonHerbicides5.26222.0427104.04950.999755108.82107.12.187.35LC-Q-Orbitrap/MS
50ChlormequatPlant growth regulators0.91122.07362.99990.9984505076.611.375.95.279.66LC-Q-Orbitrap/MS
51ChloronebFungicides10.04190.9663205.98970.99962278.610.693.17.284.62GC-Q-Orbitrap/MS
52ChlorotoluronHerbicides11.32213.078872.044490.999952088.43.285.54.482.62LC-Q-Orbitrap/MS
53ChlorprophamHerbicides12.76213.055152.99760.9996202070.911.696.36.394.64GC-Q-Orbitrap/MS
54Chlorpyrifos-methylInsecticides16.91285.9257124.98220.997922100.811.29112.491.96GC-Q-Orbitrap/MS
55ChlozolinateFungicides20.24186.9586258.97980.998101096.313.494.85.6113.911GC-Q-Orbitrap/MS
56Cis-Chlordane (alpha)Insecticides21.49370.8284374.82260.9993102083.711.8106.14.789.73GC-Q-Orbitrap/MS
57Clodinafop-propargylHerbicides17.73350.0586266.0380.999755102.24.1952.991.86LC-Q-Orbitrap/MS
58ClofentezineInsecticides18.61303.0193138.01060.99961010101.95.787.57.5998LC-Q-Orbitrap/MS
59ClomazoneHerbicides14.57204.1019127.01240.9998551053.3100.10.987.84GC-Q-Orbitrap/MS
60ClothianidinInsecticides4.7250.0157131.9670.9997505087.8586.44.480.82LC-Q-Orbitrap/MS
61CyanazineHerbicides7.63241.096214.08560.999855110.52.2100.91.686.35LC-Q-Orbitrap/MS
62CyanofenphosInsecticides24.93156.9872169.04130.9962283.34.491.93.488.12GC-Q-Orbitrap/MS
63CyanophosInsecticides14.94243.0116109.0050.999751088.47.696.62.5114.911GC-Q-Orbitrap/MS
64CycloateHerbicides18.6216.141583.085560.99992297.110.889.94.497.72LC-Q-Orbitrap/MS
65CycloxydimHerbicides18.78326.1779180.10130.9981101083.37.475.2872.57LC-Q-Orbitrap/MS
66CyfluthrinInsecticides31.18206.0601163.00750.9993202098.913.691.92.393.71GC-Q-Orbitrap/MS
67CypermethrinInsecticides31.69181.0647127.0310.9973505084.59.596.613.983.63GC-Q-Orbitrap/MS
68CyprodinilFungicides20.03224.1182210.10270.99995598.83.199.52.7935GC-Q-Orbitrap/MS
69delta-HCHInsecticides15.82180.9374218.9110.99935592.511.2104.64.695.24GC-Q-Orbitrap/MS
70DeltamethrinInsecticides33.53181.0647252.90470.9944202096.9799.58.397.45GC-Q-Orbitrap/MS
71DesmetrynHerbicides9.51214.1119172.06530.99992294.85.21012.399.42LC-Q-Orbitrap/MS
72DiallateHerbicides18.79270.047786.060060.9983101094.34.888.75.389.64LC-Q-Orbitrap/MS
73DiazinonInsecticides15.26179.1178199.06310.999922100.14.896.53.6100.94GC-Q-Orbitrap/MS
74DichlofenthionInsecticides16.71222.938224.9350.99931178.110.783.59.499.73GC-Q-Orbitrap/MS
75DichlofluanidFungicides18.3123.0138223.950.9983202085.54.789.95.193.97GC-Q-Orbitrap/MS
76DichlorvosInsecticides6.41184.976478.994350.99971173.16.393.710.579.66GC-Q-Orbitrap/MS
77DieldrinInsecticides22.47260.859579.054310.9945505086.715.399.510.881.55GC-Q-Orbitrap/MS
78DifenoconazoleFungicides18.66406.0715251.00260.9992101094.54.494.86.793.87LC-Q-Orbitrap/MS
79DiflubenzuronInsecticides17.45311.0389141.01480.9998101099.65.187.96.391.96LC-Q-Orbitrap/MS
80DimethenamidHerbicides15.03276.0816168.08420.99972284.25.889.41.684.32LC-Q-Orbitrap/MS
81DimethoateInsecticides14.03124.9822142.99270.99545588.13.6101.95.193.73GC-Q-Orbitrap/MS
82Dimethylvinphos (E)Insecticides18.29294.9688127.01550.99872593.46.3107.24.295.33GC-Q-Orbitrap/MS
83Dimethylvinphos (Z)Insecticides16.61330.9452127.01560.9996101096.94.592.55.191.33LC-Q-Orbitrap/MS
84DiniconazoleFungicides23.79268.0041232.02730.9974101088.712.591.34.8111.68GC-Q-Orbitrap/MS
85DinotefuranInsecticides3.23203.1138129.08970.9983505088.111.491.25.777.93LC-Q-Orbitrap/MS
86DioxabenzofosInsecticides12.94216.0005200.9770.999555101.59.6103.67.788.94GC-Q-Orbitrap/MS
87DipropetrynHerbicides17.21256.1586186.08110.99962294.14.4100.72.298.93LC-Q-Orbitrap/MS
88DiuronHerbicides12.8233.024172.044520.999655085.55.192.75.981.91LC-Q-Orbitrap/MS
89EdifenphosFungicides24.95109.0108172.98210.99962298.13.299.92.6101.43GC-Q-Orbitrap/MS
90Endosulfan-sulfateInsecticides25.03269.8128236.84070.9975202095.319.2111.4794.24GC-Q-Orbitrap/MS
91EPNInsecticides27.04156.9872169.04130.99982287.316.779.18.286.44GC-Q-Orbitrap/MS
92EPTCHerbicides7.75128.1071104.05310.99975586.411.180.18.276.14GC-Q-Orbitrap/MS
93EthalfluralinHerbicides12.59276.0595292.05380.99982050114.216.593.411.481.11GC-Q-Orbitrap/MS
94EthionInsecticides23.94230.973296.950840.99982279.217.291.5491.33GC-Q-Orbitrap/MS
95EthoprophosInsecticides17.05243.0633130.93860.99972293.1499.62.598.82LC-Q-Orbitrap/MS
96EtofenproxInsecticides31.87163.1117107.04920.99975589.714.9101.77.896.94GC-Q-Orbitrap/MS
97EtrimfosInsecticides17.79293.0717142.99280.99971010104.15.689.85.188.84LC-Q-Orbitrap/MS
98FenamidoneFungicides27.44268.0905237.10230.999855100.4299.3390.36GC-Q-Orbitrap/MS
99FenamiphosInsecticides17.52304.1125217.00830.99892292.79.186.74.987.76LC-Q-Orbitrap/MS
100Fenamiphos-sulfoneInsecticides10.34336.1026139.02130.99985595.84.8104.42.786.95LC-Q-Orbitrap/MS
101Fenamiphos-sulfoxideInsecticides9.78320.1076171.04760.99731010119.74.111211.899.94LC-Q-Orbitrap/MS
102FenarimolFungicides29.16138.9946251.00280.99995575.96.495.54.790.23GC-Q-Orbitrap/MS
103FenbuconazoleFungicides17.43337.1209125.01530.9998551035.694.32.488.35LC-Q-Orbitrap/MS
104FenchlorphosInsecticides17.55284.9304124.98220.997422102.28.5102.43.788.33GC-Q-Orbitrap/MS
105FenitrothionInsecticides18.08277.017124.98220.9987202073.513.1115.47.890.24GC-Q-Orbitrap/MS
106FenobucarbInsecticides11.79121.0649122.06820.999555117.69.798.35.291.54GC-Q-Orbitrap/MS
107FenpropathrinInsecticides27.45181.064797.101290.99975589.57.699.33.598.74GC-Q-Orbitrap/MS
108FenpropimorphFungicides19.13128.1069117.06970.999355100.48.898.67.51024GC-Q-Orbitrap/MS
109FensulfothionInsecticides13.29309.0375157.03180.99965599.7298.43.183.95LC-Q-Orbitrap/MS
110FenthionInsecticides18.84278.0195245.03980.99811010111.511.9102.72.9103.63GC-Q-Orbitrap/MS
111Fenthion-sulfoneInsecticides10.93311.0166142.99280.9998101097.63.896.63.692.76LC-Q-Orbitrap/MS
112Fenthion-sulfoxideInsecticides10.21295.022127.01560.999755106.13.3102.73.6107.211LC-Q-Orbitrap/MS
113FipronilInsecticides20.24366.9429212.94810.999955109.419.9102.17.995.74GC-Q-Orbitrap/MS
114Fipronil DesulfinylInsecticides17.2332.9961389.96830.99855596.118.5106.35.797.52GC-Q-Orbitrap/MS
115Fipronil-sulfideInsecticides19.86350.9479254.96990.999955112.315107.68.298.64GC-Q-Orbitrap/MS
116Fipronil-sulfoneInsecticides22.51382.9377212.94810.9998202066.55.5102.210.189.83GC-Q-Orbitrap/MS
117FluacrypyrimInsecticides24.38145.0649204.07810.99981010794.490.78.5102.410GC-Q-Orbitrap/MS
118Fluazifop-butylHerbicides23.41282.0736268.05820.99932294.18.987.11.592.63GC-Q-Orbitrap/MS
119FlucythrinateInsecticides31.7157.046181.06470.999955103.214.899.57.890.34GC-Q-Orbitrap/MS
120FluopicolideFungicides15.97382.9722172.95550.99991010994.188.85.592.74LC-Q-Orbitrap/MS
121FluquinconazoleFungicides30.38340.0395341.04280.99531010100.86.881.42.8106.812GC-Q-Orbitrap/MS
122FluridoneHerbicides14.6330.1095259.09890.999922952.6100.32.394.92LC-Q-Orbitrap/MS
123FlusilazoleFungicides17.63316.1072165.07010.999821097.74.185.95.494.96LC-Q-Orbitrap/MS
124FlutriafolFungicides12.4302.109570.040120.99965598.54.796.9480.16LC-Q-Orbitrap/MS
125FluxapyroxadFungicides27.04159.0364139.03020.99981291.87.391.13.684.45GC-Q-Orbitrap/MS
126FonofosInsecticides15.05137.0187246.02970.99992293.512.5102.43913GC-Q-Orbitrap/MS
127FosthiazateInsecticides11.16284.0536104.01650.99991010102.27.580.47.590.26LC-Q-Orbitrap/MS
128FurathiocarbInsecticides27.97163.0753194.03960.99932284.17.392.83.497.53GC-Q-Orbitrap/MS
129HaloxyfopHerbicides17.72362.039691.054310.9981202078.36.497.84.497.76LC-Q-Orbitrap/MS
130Haloxyfop-2-ethoxyethylHerbicides26.22302.019316.03450.99975595.9794.82.190.47GC-Q-Orbitrap/MS
131Haloxyfop-methylHerbicides21.21288.0035375.04780.99995595.44.190.33.792.87GC-Q-Orbitrap/MS
132HeptachlorInsecticides17.36269.813273.80690.9964505092.16.2112.713.684.44GC-Q-Orbitrap/MS
133HexachlorobenzeneFungicides13.67281.8127285.80680.99882593.813.489.47.485.73GC-Q-Orbitrap/MS
134HexaconazoleFungicides18.17314.081770.040150.999551096.13.184.55.290.37LC-Q-Orbitrap/MS
135HexythiazoxInsecticides19.53353.1079168.05760.99951010115.97.7105.99.788.36LC-Q-Orbitrap/MS
136Imazalil Fungicides11.55297.0553158.97640.9991101099.31.186.13.886.96LC-Q-Orbitrap/MS
137ImazapyrHerbicides4.63262.1184217.09720.9995551024.999.12.988.14LC-Q-Orbitrap/MS
138ImidaclopridInsecticides4.76256.0592209.05890.99971010100.24.789.23.790.84LC-Q-Orbitrap/MS
139ImidaclothizInsecticides5.06262.0157181.05420.9977202079.33.384.64.482.32LC-Q-Orbitrap/MS
140IpconazoleFungicides29.05125.0154127.01240.99992589.18.485.52.893.74GC-Q-Orbitrap/MS
141IprobenfosFungicides17.76289.101891.05430.9993202085.57.3933.793.93LC-Q-Orbitrap/MS
142IprovalicarbFungicides16.88321.2167119.08560.9996101073.28.389.54100.45LC-Q-Orbitrap/MS
143IsazofosInsecticides15.66118.9883162.04290.999955102.32.595.74.691.36GC-Q-Orbitrap/MS
144IsocarbophosInsecticides19.14135.9976120.02050.99982572.41087.99.895.74GC-Q-Orbitrap/MS
145IsofenphosInsecticides20.27213.0311121.02850.99982296.519.497.97.186.32GC-Q-Orbitrap/MS
146IsoprocarbInsecticides11.76194.117695.04920.999655113.49.899.29.887.75LC-Q-Orbitrap/MS
147IsoproturonHerbicides12.5207.14972.04450.999421097.22.489.33.8935LC-Q-Orbitrap/MS
148Isopyrazam/18.64360.1877244.08820.99992292.86.6102.83.994.43LC-Q-Orbitrap/MS
149Kresoxim-methylFungicides22.79116.0496206.08120.99985592.98.195.85.699.82GC-Q-Orbitrap/MS
150LactofenHerbicides19.2479.0826222.9770.9992101098.95.689.28.486.57LC-Q-Orbitrap/MS
151LindaneInsecticides14.52180.9371218.9110.9933102090.47.794.7692.86GC-Q-Orbitrap/MS
152LinuronHerbicides14.67249.0189159.97170.99961010102.12.797.55.497.35LC-Q-Orbitrap/MS
153MalaoxonInsecticides17.15127.0156194.98760.99945598.16.3109.64.486.44GC-Q-Orbitrap/MS
154MalathionInsecticides15.94331.042899.007710.9999101099.96.791.63.994.43LC-Q-Orbitrap/MS
155MepanipyrimFungicides16.87224.118106.06520.99972299.74.194.91.9100.74LC-Q-Orbitrap/MS
156MetaflumizoneInsecticides19.28507.1238178.04750.9994505083.49.189.76.480.76LC-Q-Orbitrap/MS
157MetalaxylFungicides17.22160.1121132.08090.9992101097.84.782.45.7107.210GC-Q-Orbitrap/MS
158MetconazoleFungicides27.69125.0154138.06640.99975597.76.6100.94.595.37GC-Q-Orbitrap/MS
159MethidathionInsecticides20.98145.0067124.98220.99985592.66108.45.695.43GC-Q-Orbitrap/MS
160MethiocarbInsecticides14.95226.0894121.06480.9996101096.62.686.53.992.84LC-Q-Orbitrap/MS
161Methiocarb-sulfoneInsecticides5.65275.1055122.07270.9995505090.44.1100.54.483.12LC-Q-Orbitrap/MS
162Methiocarb-sulfoxideInsecticides5.16242.0841185.06310.99961010106.83.688.73.790.95LC-Q-Orbitrap/MS
163MetolachlorHerbicides17.15284.1408148.11210.9998101097.22.794.84.8924LC-Q-Orbitrap/MS
164MetolcarbInsecticides9.31108.05779.054310.999755112.99.1105.99.690.712GC-Q-Orbitrap/MS
165MetrafenoneFungicides18.42409.064226.97030.9998101079.36.795.35.792.45LC-Q-Orbitrap/MS
166MetribuzinHerbicides16.93198.0696144.04650.99751010938.775.77.5103.111GC-Q-Orbitrap/MS
167MevinphosInsecticides6.23225.052127.01550.99952275.85.989.63.784.83LC-Q-Orbitrap/MS
168MirexInsecticides28.83269.8128273.80670.9991101081.710.675.35.4111.79GC-Q-Orbitrap/MS
169MonocrotophosInsecticides4.24224.068127.01550.9997210955.678.45.2101.12LC-Q-Orbitrap/MS
170MonolinuronHerbicides10.17215.058126.01070.999955104.12.21032.690.44LC-Q-Orbitrap/MS
171MyclobutanilFungicides22.65179.0244181.02140.999355104.42.796.84.386.85GC-Q-Orbitrap/MS
172NapropamideHerbicides17.17272.1641171.08060.99992298.92.696.73.1992LC-Q-Orbitrap/MS
173NorflurazonHerbicides13.21304.0454284.03960.9999510100.71.990.63.994.17LC-Q-Orbitrap/MS
174OmethoateInsecticides3.05214.0296142.99270.9996101097.84.991.410.6113.78LC-Q-Orbitrap/MS
175OxadiazonHerbicides22.5174.9587258.03230.999425100.19.9103.12.2982GC-Q-Orbitrap/MS
176OxadixylFungicides23.87132.0809233.09220.99661186.68.776.812.281.610GC-Q-Orbitrap/MS
177OxyfluorfenHerbicides22.72252.0395317.0060.9993101092.714.892.64112.413GC-Q-Orbitrap/MS
178PaclobutrazolPlant growth regulators15.83294.136470.040130.999451098.32.787.14.390.55LC-Q-Orbitrap/MS
179ParathionInsecticides18.98291.0326155.00360.9987505084.19.182.710.2845GC-Q-Orbitrap/MS
180PendimethalinHerbicides19.92252.098191.06880.99915578.79.392.16.888.93GC-Q-Orbitrap/MS
181Pentachloroaniline/16.36262.8627266.85680.997522107.514.2919.585.46GC-Q-Orbitrap/MS
182Pentachloroanisole/13.87262.8389236.84090.9993558510.999.89.990.73GC-Q-Orbitrap/MS
183PenthiopyradFungicides17.95360.1346177.02710.999322908.890.92.390.24LC-Q-Orbitrap/MS
184PhenothrinInsecticides28.19183.080481.069960.99985594.39.310213.994.43GC-Q-Orbitrap/MS
185PhenthoateInsecticides20.48273.9883245.99330.999755114.612.8100.49.291.64GC-Q-Orbitrap/MS
186PhorateInsecticides18.23261.020175.026440.99181020116.29.897.35.995.42LC-Q-Orbitrap/MS
187Phorate-SulfoneInsecticides11.8293.0096171.0240.9995202090.82.387.34.694.45LC-Q-Orbitrap/MS
188Phorate-SulfoxideInsecticides11.48277.0147114.96140.99981010106.22.2105.410.498.75LC-Q-Orbitrap/MS
189PhosaloneInsecticides28.22182.0003121.04140.999655104.811.697.86.797.66GC-Q-Orbitrap/MS
190PhosmetInsecticides14.19318.0018160.03940.999420207815.295.610.295.32LC-Q-Orbitrap/MS
191PhosphamidonInsecticides7.68300.076127.01560.999101071.92.781.313.58911LC-Q-Orbitrap/MS
192PhoximInsecticides18.28299.061129.04480.99971010105.65.890.84.4905LC-Q-Orbitrap/MS
193PicoxystrobinFungicides17.68368.11145.0650.99692020803.3996.3101.23LC-Q-Orbitrap/MS
194Piperonyl ButoxideInsecticides26.16176.0832119.08560.99975596.37.3112.67.288.15GC-Q-Orbitrap/MS
195PirimicarbInsecticides7.76239.149372.044550.999955102.22.695.6187.14LC-Q-Orbitrap/MS
196Pirimiphos-methylInsecticides18.02306.1032108.05570.999922103.2696.22.994.64LC-Q-Orbitrap/MS
197PretilachlorHerbicides18.84312.1719252.1150.9994551135.496.63.789.53LC-Q-Orbitrap/MS
198ProchlorazFungicides18.09376.037770.028920.99971010105.13.790.66.292.36LC-Q-Orbitrap/MS
199ProcymidoneFungicides20.64283.0162285.01320.9989510110.37.181.73.4119.811GC-Q-Orbitrap/MS
200ProfenofosInsecticides19.07372.9418302.86430.9997101098.72.195.35.3886LC-Q-Orbitrap/MS
201PrometrynHerbicides17.85241.1357226.11220.998355937.893.8996.13GC-Q-Orbitrap/MS
202PropamocarbFungicides3189.1596102.0550.9999101079.83.998.913.586.812LC-Q-Orbitrap/MS
203PropanilHerbicides16.85160.9793217.00550.99961283.46.390.73.185.65GC-Q-Orbitrap/MS
204PropaphosInsecticides17.98305.0968221.00330.99962281.68.688.84.77119LC-Q-Orbitrap/MS
205PropargiteInsecticides19.69368.188481.069960.999755117.55.798.9492.54LC-Q-Orbitrap/MS
206PropazineHerbicides14.54230.1164146.02290.999911106.22.11021.899.72LC-Q-Orbitrap/MS
207ProphamHerbicides9.26179.09493.05740.99282591.68.796.26.294.42GC-Q-Orbitrap/MS
208PropiconazoleFungicides25.27172.9556174.95260.99925590.78.592.89.591.82GC-Q-Orbitrap/MS
209PropyzamideHerbicides15.14172.9556254.01350.9992278.411.998.84.591.52GC-Q-Orbitrap/MS
210Prothioconazole-desthioFungicides17.14312.06670.040140.999155103.42102.82.993.56LC-Q-Orbitrap/MS
211ProthiofosInsecticides20.39344.9699258.91490.9993505084.910.672.94.580.24LC-Q-Orbitrap/MS
212PymetrozineInsecticides2.76218.1034105.04480.9963505071.410.693.411.48910LC-Q-Orbitrap/MS
213PyraclostrobinFungicides18.31388.1054163.06290.99952593.87.5103.65.699.75LC-Q-Orbitrap/MS
214PyridabenInsecticides20.22365.1444147.11690.999855101.93.899.34.391.15LC-Q-Orbitrap/MS
215PyridaphenthionInsecticides16.58341.0715189.0660.99972299.24101.83.389.95LC-Q-Orbitrap/MS
216PyrimethanilFungicides15.51198.1026183.07910.99752272.58.897.77.279.45GC-Q-Orbitrap/MS
217PyriproxyfenInsecticides19.44322.143396.04440.99981190.95.41024.197.94LC-Q-Orbitrap/MS
218QuinalphosInsecticides20.51146.0475157.0760.999822104.16.7101.82.995.34GC-Q-Orbitrap/MS
219QuinoxyfenFungicides25.06237.0585306.99640.99992285.56.1100.83.299.73GC-Q-Orbitrap/MS
220QuintozeneFungicides14.57234.8438238.83790.9995101074.610.674.211.9112.314GC-Q-Orbitrap/MS
221Quizalofop-ethylHerbicides19.03373.0945299.05810.999955104.84105.3292.77LC-Q-Orbitrap/MS
222ResmethrinInsecticides20.38339.1951128.06210.99855574.13.572.85.680.94LC-Q-Orbitrap/MS
223SedaxaneFungicides28.88159.0365130.06520.99981010876.285.75.9104.712GC-Q-Orbitrap/MS
224SimazineHerbicides8.35202.0851132.03240.9998101098.81.688.42.592.45LC-Q-Orbitrap/MS
225Spinosyn AInsecticides18.35732.4695142.12280.9997205094.36.9867.785.54LC-Q-Orbitrap/MS
226Spinosyn DInsecticides18.73746.4852142.12280.9955505080.717.797.5680.73LC-Q-Orbitrap/MS
227SpirodiclofenInsecticides19.93411.112171.085680.9995101092.44.7916.496.45LC-Q-Orbitrap/MS
228SpirotetramatInsecticides17374.1957216.1020.9997202087.79.491.59.489.43LC-Q-Orbitrap/MS
229Spirotetramat-enolInsecticides11.3302.1748216.1020.999655102.13100.62.286.65LC-Q-Orbitrap/MS
230SpiroxamineFungicides15.41298.2737144.13840.99972287.68.599.55.387.75LC-Q-Orbitrap/MS
231SulfotepInsecticides17.84323.0296114.96140.99992297.66.696.1395.35LC-Q-Orbitrap/MS
232SulprofosInsecticides19.63323.035218.97010.9967101079.99.8825.581.410LC-Q-Orbitrap/MS
233TebuconazoleFungicides17.87308.152125.01530.99955576.28.595.85962LC-Q-Orbitrap/MS
234TerbufosInsecticides14.94230.9733174.91060.992101091.68.5117.64.610414GC-Q-Orbitrap/MS
235Terbufos-sulfoneInsecticides20.08199.001170.96980.999955117.67.8116.87.293.23GC-Q-Orbitrap/MS
236Terbufos-SulfoxideInsecticides14.77305.0459130.93860.9981205098.97.693.62.784.63LC-Q-Orbitrap/MS
237TerbumetonHerbicides11.1226.1661170.10390.9952202078.1895.32.583.57LC-Q-Orbitrap/MS
238TerbuthylazineHerbicides15.23230.1164174.05430.99972297.94.797.21.4102.22LC-Q-Orbitrap/MS
239TetradifonInsecticides28158.9666226.88870.99975590.23.793.33.893.93GC-Q-Orbitrap/MS
240TetramethrinInsecticides19.12332.1852164.07070.99981196.113.793.65.896.44LC-Q-Orbitrap/MS
241ThiabendazoleFungicides4.78202.0432175.03250.99955592.93.895.54.282.86LC-Q-Orbitrap/MS
242ThiaclopridInsecticides6.22253.0307126.01060.999755106.64.698.62.683.95LC-Q-Orbitrap/MS
243ThiamethoxamInsecticides4.04292.0263131.9670.9984202089.15.594.84.791.95LC-Q-Orbitrap/MS
244ThiobencarbHerbicides18.47258.0711125.01540.99975598.53.498.26.492.35LC-Q-Orbitrap/MS
245Thiophanate-methylFungicides8.05343.0526151.03260.9904505071.88.371.56.279.89LC-Q-Orbitrap/MS
246TolfenpyradInsecticides19.34384.147197.09620.99965596.86.2974.789.56LC-Q-Orbitrap/MS
247TolylfluanidFungicides17.88346.9848137.02950.998250501008.193.17.382.43LC-Q-Orbitrap/MS
248TriadimefonFungicides16.2294.1197.07290.999355101.8497.32.890.97LC-Q-Orbitrap/MS
249TriadimenolFungicides16.5296.115670.040160.9999558413.190.72.692.82LC-Q-Orbitrap/MS
250TriazophosInsecticides16.73314.0718162.06620.99952295.61.9105.84.396.45LC-Q-Orbitrap/MS
251TrichlorfonInsecticides4.93256.9295127.01550.9987202088.35.193.83.892.53LC-Q-Orbitrap/MS
252TrifloxystrobinFungicides18.77409.1364186.05250.99845598.25.51022.692.25LC-Q-Orbitrap/MS
253TriflumizoleFungicides18.8346.0923278.05540.9999101076.712.281.78.385.17LC-Q-Orbitrap/MS
254Trinexapac-ethylPlant growth regulators12.72253.106769.033660.9964202085.29.596.211.91146LC-Q-Orbitrap/MS
255UniconazoleFungicides22.49234.0429165.01020.999755106.23.5972.589.56GC-Q-Orbitrap/MS
256VinclozolinFungicides17.09212.0029197.98720.99945597.87.3105.83.590.86GC-Q-Orbitrap/MS
257Warfarin/15.51309.1118163.03910.999922100.85.7102.73.991.13LC-Q-Orbitrap/MS
258ZoxamideFungicides17.89336.0315186.9710.99995591.36.2103.83.1977LC-Q-Orbitrap/MS
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MDPI and ACS Style

Xie, Y.; Wu, X.; Song, Y.; Sun, Y.; Tong, K.; Yu, X.; Fan, C.; Chen, H. Screening of 258 Pesticide Residues in Silage Using Modified QuEChERS with Liquid- and Gas Chromatography-Quadrupole/Orbitrap Mass Spectrometry. Agriculture 2022, 12, 1231. https://doi.org/10.3390/agriculture12081231

AMA Style

Xie Y, Wu X, Song Y, Sun Y, Tong K, Yu X, Fan C, Chen H. Screening of 258 Pesticide Residues in Silage Using Modified QuEChERS with Liquid- and Gas Chromatography-Quadrupole/Orbitrap Mass Spectrometry. Agriculture. 2022; 12(8):1231. https://doi.org/10.3390/agriculture12081231

Chicago/Turabian Style

Xie, Yujie, Xingqiang Wu, Yanling Song, Yini Sun, Kaixuan Tong, Xiaoxuan Yu, Chunlin Fan, and Hui Chen. 2022. "Screening of 258 Pesticide Residues in Silage Using Modified QuEChERS with Liquid- and Gas Chromatography-Quadrupole/Orbitrap Mass Spectrometry" Agriculture 12, no. 8: 1231. https://doi.org/10.3390/agriculture12081231

APA Style

Xie, Y., Wu, X., Song, Y., Sun, Y., Tong, K., Yu, X., Fan, C., & Chen, H. (2022). Screening of 258 Pesticide Residues in Silage Using Modified QuEChERS with Liquid- and Gas Chromatography-Quadrupole/Orbitrap Mass Spectrometry. Agriculture, 12(8), 1231. https://doi.org/10.3390/agriculture12081231

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