Huidong Li

Risk assessment of pesticide residues in dietary intake of celery in China

OBJECTIVE Residue risk assessment of pesticides in celery was conducted to provide a scientific basis for agricultural regulation policies and working procedures. METHODS Three hundred samples from eight main growing regions in China were collected and pesticide residue analyses were performed using GC-MS/MS and LC-MS/MS methods. Both chronic and acute intake risk of pesticides were assessed. Furthermore, intake risk of each detected pesticide was ranked according to a predefined ranking matrix. RESULTS (1) Out of these 300 samples, 175 were revealed to contain one or more pesticide residues. Twenty-five pesticides were identified in total, out of which, carbofuran was found to exceed the maximum residue limit. (2) Chronic and acute intake risks were evaluated and lie in between 0 and 1.80 and between 0.05 and 28.0 for these twenty-five pesticides, respectively. (3) Intake risk of individual pesticide was ranked; five pesticides, including avermectin, triazophos, chlorpyrifos, dimethoate oxygen, and carbofuran posed the highest risks. CONCLUSION Pesticide residues were detected in more than 58% celery samples in our study. Most pesticides have a residue level lower than their maximum residue limit and pose low chronic and acute dietary intake risk. However, usage of some pesticides like carbofuran should be closely monitored and regulated in the future.

Simultaneous analysis of kasugamycin and validamycin-A in fruits and vegetables using liquid chromatography-tandem mass spectrometry and consecutive solid-phase extraction

A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for simultaneous determination of two hydrophilic aminoglycosides, kasugamycin and validamycin-A, in a variety of matrices (apples, cabbage, cucumbers, lettuce, tomatoes, and eggplant) has been developed. The proposed method provides sufficient sensitivity and excellent chromatographic performance using a special ReproSil 100 C18 column with 0.1% formic acid as the mobile phase additive. Accurate mass information for both analytes was obtained based on time-of-flight (TOF) mass spectrometry. The methanol/water (70 : 30, v/v) with pH adjusted to 5.5 was selected as the extraction solvent. The combination of hydrophilic–hydrophobic-balanced (HLB) cartridges with strong cation exchange SCX cartridges was used to purify the extracts with strongly polar compounds and satisfactory results were obtained. The consecutive solid-phase extraction minimized signal suppression/enhancement which led to matrix effects in the range of −12.6 to 6.11% only. Recovery experiments were performed for both compounds at three levels (50, 100, and 500 μg kg−1) in six different matrices and yielded good recoveries ranging from 81.7% to 108% with relative standard deviation values below 13%. The limits of quantification (LOQs) for kasugamycin and validamycin-A were 4.1 μg kg−1 and 1.0 μg kg−1, respectively.

Monitoring and probabilistic risk assessment of chlorothalonil residues in vegetables from Shandong province (China)

The aims of this study were to investigate the contamination status of chlorothalonil pesticide residues in vegetables from Shandong province, and to assess the potential risk of chlorothalonil to consumers based on vegetable consumption and body weight using an improved non-parameter probabilistic model. The results showed that Young children (8 months-6 years old) were more sensitive than General population(above 1year-old). In general, the health risk of chlorothalonil residues to 2 consumer groups via vegetable exposure was low, and the level of residual chlorothalonil was below the Acute Reference Dose (ARfD). This result would provide useful information for re-evaluating pesticides and for revising the chlorothalonil standard in vegetables.

Determination and risk assessment of sixteen polycyclic aromatic hydrocarbons in vegetables

ABSTRACT Polycyclic aromatic hydrocarbons (PAHs) are a group of organic environmental pollutants posing a potential risk to human health. This study was constructed to investigate the presence of 16 PAHs in six commonly consumed vegetables collected from the markets in Shandong, China by a quick, easy, cheap, effective, rugged, safe (QuEChERS)-based extraction method coupled with gas chromatography–mass spectrometry (GC–MS). Our results showed that the vegetables were polluted with PAHs at an alarming level, of which celery contained the highest total concentration of PAHs (Σ16 PAH), whereas cucumbers contained the lowest Σ16 PAH. Besides, the dietary exposure of PAHs was assessed in these vegetables based on the maximum Σ16 PAH. The results showed that the populations in Shandong were exposed to 23–213 ng/d of PAHs through these six vegetables, suggesting that vegetables are the major sources of PAHs in the diet. Hence, it is necessary to monitor the PAH levels in vegetables. Our study provides guidance for future legislative actions regarding PAH levels in vegetables in China.

Determination of fipronil and its metabolites in eggs by UPLC-QqLIT-MS/MS with multistage mass spectrometry mode

Abstract A fast, sensitive, and reliable method for the determination of fipronil and its metabolites (fipronil-sulfone, fipronil sulfide, and fipronil-desulfynil) in eggs was developed by a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) pretreatment method and ultra-performance liquid chromatography-quadrupole-linear ion trap mass spectrometry (UPLC-QqLIT-MS/MS). The proposed multistage mass spectrometry (MS3) method provides sufficient sensitivity and excellent reproducibility. The four analytes were separated by a Waters ACQUITY UPLC® BEH C18 column and detected by AB Sciex QTRAP® 5500. The mean recoveries for the four analytes ranged from 90.7% to 105% with relative standard deviations (RSDs) of 0.7% to 4.9%. The calibration curve showed a good linearity within the concentration range of 0.05 to 20 ng/mL. The correlation coefficients (R2) were higher than 0.999. The limits of detection (LODs) obtained from the experimental results for fipronil, fipronil-sulfone, fipronil-sulfide, and fipronil-desulfinyl were 0.06, 0.02, 0.05, and 0.04 µg/kg, respectively. The MS3 method was successfully applied to detect fipronil and its metabolites in 60 egg samples purchased from Chinese supermarkets, and wholesale markets. Graphical Abstract

Simultaneous determination of kasugamycin and validamycin-A residues in cereals by consecutive solid-phase extraction combined with liquid chromatography–tandem mass spectrometry

ABSTRACT Two polar aminoglycosides, kasugamycin and validamycin-A, were determined in cereals (brown rice, wheat and corn) by high-performance liquid chromatography–tandem mass spectrometry. The analytes were extracted from samples using methanol and water (70:30, v/v) at pH 5.5, purified using both a hydrophilic–hydrophobic-balanced cartridge and a strong cation-exchange cartridge, and then analysed using multiple reaction monitoring in positive electrospray ionisation mode with a special ReproSil 100 C18 high-performance liquid chromatography column. This newly proposed method yielded good sensitivity and excellent chromatographic performance. The limits of quantification for kasugamycin and validamycin-A were 4.1 µg/kg and 1.0 µg/kg, respectively. The recoveries for both compounds at three fortification levels (4, 100 and 500 µg/kg for kasugamycin; 1, 10 and 100 µg/kg for validamycin-A) ranged from 75% to 110%, and the relative standard deviations were below 15%.