*3.5. Terminal Residue and Dietary Risk Assessment*

### 3.5.1. Residue Definition

According to the residue definition of risk assessment (JMPR, 2013), the total residue of IFT was calculated according to the following equation:

$$\mathbf{C\_{IFT}} = \mathbf{C\_{IFT}} + \mathbf{C\_{IFT-DKN}} \tag{2}$$

According to the Pesticide Registration Residue Test Residues and the Catalog of Residues for Dietary Risk Assessment in Foods of Plant Origin, the total residues of ATR were estimated with the following equation:

$$\mathbf{C\_{ATR}} = \mathbf{C\_{ATR}} + \mathbf{C\_{DEA}} \times 1.15 + \mathbf{C\_{DIA}} \times 1.24 + \mathbf{C\_{DACT}} \times 1.48 + \mathbf{C\_{HA}} \times 1.09 \tag{3}$$

where CIFT, CIFT-DKN CATR, CDEA, CDIA, CDACT and CHA are the concentrations of IFT, IFT-DKN, ATR, DEA, DIA, DACT and HA. 1.15, 1.24, 1.48 and 1.09 are the molecular weight ratios of DEA, DIA, DACT and HA to ATR, respectively. If the residues of IFT, ATR and their metabolites were lower than their limited limits (LOQ), the value of LOQ was considered directly, and the Csum was calculated directly based on the sum of LOQ values of all compounds.

#### 3.5.2. Dietary Risk Assessment

The risk quotient (RQc) was used to assess further the risk of chronic dietary intake of IFT and ATR and was calculated according to the following equation.

$$\text{NEDI} = \sum (\text{STMR} \times \text{F}\_{\text{i}}) / \text{bw} \tag{4}$$

$$\text{RQ}\_{\text{C}} = \text{NEDI} / \text{ADI} \times 100\% \tag{5}$$

where NEDI (mg kg−<sup>1</sup> bw day−<sup>1</sup> ) is the national estimated daily intake, and STMR (mg kg−<sup>1</sup> ) is the standard median residual value. F<sup>i</sup> (kg) represents the consumption of a given food by a specific population. bw is the average body weight, kg. The ADI of IFT and ATR are both 0.02 mg kg−<sup>1</sup> bw day−<sup>1</sup> .

#### **4. Conclusions**

We established an improved QuEChERS pre-treatment and ultra-high performance liquid chromatography–tandem mass spectrometry method to detect ATR, IFT and metabolites. The technique has good linearity, accuracy, and precision. Under GAP conditions, samples of fresh maize, corn kernels, and corn straw after pesticide application were collected in six provinces in China. The results showed that the residues of ATR, IFT, and their metabolites in fresh corn and corn kernels were all lower than LOQ. IFT was also

not detected in corn straw, but ATR residue, less than 0.135 mg kg−<sup>1</sup> , was detected. All consumers' risk quotients (RQc) were below 100%, indicating that the chronic risk of ATR and IFT is acceptable. It should be noted that children (2–3 years old) and women have a relatively higher risk of chronic diseases than other groups.

**Author Contributions:** Data curation, J.C.; Funding acquisition, J.C.; Methodology, T.P., Y.W., Y.Q., P.R. and J.L.; Project administration, S.Q.; Resources, S.Q. and J.L.; Software, J.L.; Supervision, S.Q.; Validation, T.P., Y.W., Y.Q. and P.R.; Visualization, J.C., T.P., Y.W., Y.Q. and P.R.; Writing—original draft, J.C.; Writing—review & editing, S.Q. and J.L. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the Doctor's reward funds for working in Shanxi Province (SXBYKY2022087), Startup Foundation for Doctors of Shanxi Agricultural University (2021BQ127) and Shanxi Applied Basic Research Program Science–Youth Technology Research Fund (202103021223149).

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data presented in this study are available from the authors upon request.

**Acknowledgments:** We would like to thank Zhang Junwen, Su Hailing and Zhu Li'ao for their support in this field trial, and our colleague Wang Xia' technical support.

**Conflicts of Interest:** The authors declare no conflict of interest.

**Sample Availability:** Samples of the compounds are available from the authors.

#### **References**


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