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Background: No single pure enantiomeric pesticide residues was investigated and set regulations for tea quality safety and risk assessment. Objective: Due to lack of chiral pesticide analysis method and data, the Maximum residue limits (MRLs) about the chiral pesticides in tea was unknown. Method: An analytical method for the determination of chiral pesticide residues by QuEChERS combined chiral liquid chromatography quadruple/linear ion trap mass spectrometry (LC-MS/MS-Qtrap) was developed and applied to the analysis of various teas. Results: The mean recoveries for pesticides enantiomers ranged from 75.9% to 112.4%. Reproducibility represented by relative standard deviation percentage was 10% or less. Good linearity was achieved for all enantiomers with determination coefficients (r²) greater than 0.99. The detection of limit (CCa) and quantification of limit (CCb) were 0.2 ~1 mg/kg and 0.5~5 mg/kg, respectively. Conclusions: The method was suitable for monitoring the enantiomeric pesticide residues in various teas. Highlights: Enantioselective multiclass pesticide residues were determined in various teas by LC-MS/MS-Qtrap, additional Qtrap scan functions greatly enhance the performance of screening, confirmation, and identification of chiral pesticides. [ABSTRACT FROM AUTHOR]

The article describes a method for simultaneous extraction of coffee flavor compounds trigonelline, nicotinic acid and caffeine in Yunnan Arabica Coffee to be used for quality control (QC) of raw materials and monitoring of roasting condition. The method of extraction was based on microwave-assisted extraction (MAE) and separation of the three flavor compounds by high pressure liquid chromatography (HPLC) with two chromatographic columns in series.

Artemisinin (an antimalaric compound) is isolated as the active compound of the medicinal plant Artemisia annua L. A simple, rapid, and high-efficient method of extraction is developed, in which it is extracted by matrix solid-phase dispersion (MSPD) and directly analyzed by post-column derivatization high-performance liquid chromatography (HPLC). The quantitation results from the MSPD method are compared with two conventional liquid solvent extraction processes, Soxhlet and ultrasonic wave by F-test, and the result indicates no significant difference. The production rate of Artemisinin during wild plant growth (tested over two years, acquired from Yunnan, provincial Yuan Yan country) is determined. The recovery range of determination is 88.1–91.2%. The relative standard deviation (RSD) is 4.55–6.43%. The limits of detection are 0.1 µg/mL, and the limits of quantitation are 0.5 µg/mL. [ABSTRACT FROM AUTHOR]