ABSTRACT
In the present study, orthosulfamuron residues were extracted from fatty (unpolished) rice and rice straw using a modified QuEChERS method and analyzed using liquid chromatography-tandem mass spectrometry. The matrix-matched calibration was linear over the concentration ranges of 0.01-2.0 mg/kg with determination coefficient (R (2)) ⩾ 0.997. The recovery rates at two fortification levels (0.1 and 0.5 mg/kg) were satisfactory and ranged between 88.1% and 100.6%, with relative standard deviation (RSD) <8%. The limit of quantitation, 0.03 mg/kg, was lower than the maximum residue limit, 0.05 mg/kg, set by the Ministry of Food and Drug Safety in the Republic of Korea. The developed method was applied successfully to field samples harvested at 116 days and none of the samples were positive for the residue.
ABSTRACT
To investigate adulteration in commercial chili powder, the volatile organic compounds of healthy and infected powdered chili pepper were characterized using a solvent-free solid injector (SFSI) coupled with gas chromatography/mass spectrometry (GC/MS). Except for one compound (capillary compound for blank), 43 compounds were identified in healthy and infected chili powder. Specifically, 31, 36, and 41 compounds were identified in healthy, medium-infected, and severely infected chili powder. Among these compounds, acetic acid (13.77%), propanal (2.477%), N-methylpyrrole (1.986%), and 2-methyl-propanal (1.768%) were leading volatiles in the healthy chili powder. In contrast, infected chili powder contained 9,12-octadecadienoic acid, ethyl ester (15.984%), acetic acid (11.249%), hexadecanoic acid, methyl ester (3.3%), N-methylpyrrole (3.221%), and 2-furanmethanol (2.629%) as major compounds. Trimethylamine and isosorbide were detected in both medium and severely infected chili, but not in healthy chili. This means that these compounds could be used as biomarkers to distinguish between healthy and infected chili. The proposed technique was applied to 12 commercial chili powders, and trimethylamine and isosorbide were detected in six samples. These results suggest that a contaminated chili that was added to a healthy one could be successfully identified by a combination of the SFSI and GC/MS.
Subject(s)
Capsicum/chemistry , Food Contamination , Gas Chromatography-Mass Spectrometry/methods , Volatile Organic Compounds/chemistry , Acetates/analysis , Acetic Acid/analysisABSTRACT
This paper describes a comparison of the properties of the three versions of the QuEChERS method (quick, easy, cheap, effective, rugged and safe) - the original (unbuffered), acetate-buffered, and citrate-buffered methods - for the determination of fenobucarb residues in beef muscles via liquid chromatography-electrospray ionisation tandem mass spectrometry (LC-ESI(+)-MS/MS). The recovery results were good for all the versions; however, the acetate-buffered version gave higher and more consistent recoveries for fenobucarb than the other versions. Performance characteristics, such as linearity, accuracy, and precision were determined. Matrix-matched standard calibration was used for quantification, obtaining recoveries in the range of 83.7-93.4% with relative standard deviations of <5%, at two spiking levels: 10 and 40 µg/kg. The limits of detection (LOD) and quantification (LOQ) were estimated to be 1.5 and 5 µg/kg, respectively. Finally, the method was applied to the analysis of 15 market samples, and no residues were found over the limit of quantification. The method developed was found able to determine the analyte with satisfactory intensity and accuracy.
