Method Validation, Residues and Dietary Risk Assessment for Procymidone in Green Onion and Garlic Plant

Abstract

Procymidone is used as a preventive and curative fungicide to control fungal growth on edible crops and ornamental plants. It is one of the most frequently used pesticides and has a high detection rate, but its residue behaviors remain unclear in green onion and garlic plants (including garlic, garlic chive, and serpent garlic). In this study, the dissipation and terminal residues of procymidone in four matrices were investigated, along with the validation of the method and risk assessment. The analytical method for the target compound was developed using gas chromatography-tandem mass spectrometry (GC-MS/MS), which was preceded by a Florisil cleanup. The linearities of this proposed method for investigating procymidone in green onion, garlic, garlic chive, and serpent garlic were satisfied in the range from 0.010 to 2.5 mg/L with R2 > 0.9985. At the same time, the limits of quantification in the four matrices were 0.020 mg/kg, and the fortified recoveries of procymidone ranged from 86% to 104%, with relative standard deviations of 0.92% to 13%. The dissipation of procymidone in green onion and garlic chive followed first-order kinetics, while the half-lives were less than 8.35 days and 5.73 days, respectively. The terminal residue levels in garlic chive were much higher than those in green onion and serpent garlic because of morphological characteristics. The risk quotients of different Chinese consumer groups to procymidone in green onion, garlic chive, and serpent garlic were in the range from 5.79% to 25.07%, which is comparably acceptable. These data could provide valuable information on safe and reasonable use of procymidone in its increasing applications.

Keywords: garlic plant; green onion; procymidone; residues; risk assessment.

Figure 1

Schematic diagram of different varieties of green onion and parts of the garlic plant. (A) Welsh onion (Allium fistulosum L. var. giganteum Makino); (B) chive (Allium schoenoprasum L.); (C) serpent garlic (Allium sativum L. var. ophioscorodon (Link) Döll); (D) garlic chive (Allium sativum L. var. sativum); (E) garlic (Allium sativum L.).

Figure 2

Chromatogram of different cleanup conditions. Black line: blank garlic sample; blue line: garlic sample purified with NH₂ column; green line: garlic sample purified with Florisil column.

Figure 3

Typical chromatograms of procymidone in green onion (A–D), garlic chive (E–H), serpent garlic (I–L), and garlic (M–P). (A,E,I,M) are for the blank sample; (B,F,J,N) are for the solvent standard at 0.04 mg/kg; (C,G,K,O) are for the matrix standard at 0.04 mg/kg; and (D,H,L,P) are for the spiked sample at 0.02 mg/kg.

Figure 4

The dissipation of procymidone at different experiment sites. (A) Green onion; (B) garlic chive.

Figure 5

Terminal residues of procymidone for different spraying times in green onion. The asterisks represent statistically significant differences between two spraying times on the same interval day (p < 0.05). (A) low dosage; (B) high dosage.

Figure 6

Terminal residues of procymidone for different spraying times in garlic chive. The asterisks represent statistically significant differences between two spraying times on the same interval day (p < 0.05). (A) low dosage; (B) high dosage.

Figure 7

Terminal residues of procymidone for different spraying times in serpent garlic. The asterisks represent statistically significant differences between two spraying times on the same interval day (p < 0.05). (A) low dosage; (B) high dosage.

Figure 8

Terminal residues of procymidone in garlic chive, serpent garlic, and garlic in Beijing.

Figure 9

Chronic dietary risk for different consumer groups at different ages.