A high-throughput screening and quantification method for 479 pesticides in green tea was established based on solid-phase extraction combined with liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). Pesticides were extracted from samples using an optimized SPE (TPT cartridges) procedure. LC-QTOF-MS in All Ions MS/MS scan mode acquired full MS data for quantification and product ion spectra for identification. LC-QTOF-MS quantification was achieved using matrix-matched standard calibration curves to achieve the optimal method accuracy. The method performance characteristics included the linearity, overall recovery, precision, and measurement uncertainty being evaluated. The validation results exhibited a good sensitivity with the LOQs of 5–55 µg/kg, which was satisfactory for their MRLs in China or the EU. The recoveries of more than 92.7% of the 479 pesticides in green tea were 70–120% at the three spiked levels with a precision of ≤20%. Finally, this method was employed to analyze 479 pesticides in 95 tea samples from markets in China. The test results of the tea samples showed that tolfenpyrad, buprofezin, and pyridaben were found with lower concentrations. The method has effectively improved the determination efficiency of pesticide residue screening by high-resolution mass spectrometry in green tea.

Background: Even though the use of β-agonists in livestock has been banned in many countries, β-agonists abuse is still out of control owing to time-consuming and complicated determination techniques. Objective: This study applied ambient thermal desorption electrospray ionization mass spectrometry (TD-ESI/MS) as a new strategy for rapidly screening seven β-agonists. As it does not require pretreatment, this method allows on-site and real-time detection. Method: Samples were collected directly using a simple metal probe. Analytes on the probe were desorbed and ionized by TD-ESI, after which analyte ions were detected using a triple quadrupole mass analyser. Results: The results showed that a thermal desorption temperature of 320°C and nebulizer pressure of 3 psi demonstrated the highest sensitivity. Excellent linear relationships were obtained in concentrations ranging from 10 to 400 μg/kg. The limit of detection of the method was 1–10 μg/kg with RSDs of 7.2–14.6%. A positive sample was verified using HPLC coupled with triple quadrupole tandem mass spectrometry, consistent with the results from TD-ESI/MS. Conclusion: This method was the first to apply TD-ESI/MS to rapid analyse β-agonists in livestock hair and was proven to be accurate, fast, and environmentally friendly. Because qualitative screening for each analysis was completed within approximately 1 min, the method could contribute to preventing non-compliance in the flow of animal-derived food to the market. Highlights: This method was a promising method for the rapid screening of β-agonists in livestock hair at any time of breeding without imposing any harm to animal which proven to be a rapid, in situ, and non-destructive detection technique without any pretreatment.

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.

Western-style pork products have attracted many modern urban consumers, and these products have rapidly entered the Chinese market. The current hazard analysis of processed meat products mainly focuses on processing hazards (PAHs, microorganisms, and food additives), with less attention to veterinary drug residues. According to the survey results, the residues of antimicrobial drugs (sulfonamides and quinolones) in pork and its products in China are a severe problem, which may cause metabolic reactions, toxic effects, or enhance drug resistance. This study applied a modified QuEChERS method combined with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MSMS) to develop a rapid and sensitive method for determining antimicrobial drugs in bacon and ham was successfully evaluated methodologically by EU 2002/657/EC. This study used a three-level, three-factor Box–Behnken design (BBD) to optimize the QuEChERS method by response surface methodology. The excellent linearity of the calibration curve was shown in the corresponding concentration range with a coefficient of determination greater than 0.99. The values of decision limit (CCα) and detection capability (CCβ) were in the range of 10.9–31.3 μg/kg and 11.8–52.5 μg/kg, respectively. The method successfully detected two trace levels of antimicrobial drugs in commercially available samples, including sulfadiazine and moxifloxacin.