Risk assessment,dissipation behavior and persistence of quinalphos in/on green pea by gas chromatography with electron capture detector

Chemical investigation was carried out to examine the risk assessment, dissipation behavior, persistence, and half‐life period of quinalphos in/on green pea fruit by spraying quinalphos at fruiting stage followed by another application after 10‐day interval. The samples were extracted by using the quick, easy, cheap, effective, rugged, and safe method, and the residues of quinalphos were analyzed by gas chromatography with electron capture detector. Herein, we report a novel, accurate, and cost‐effective gas chromatography method for the determination of average deposits of quinalphos in/on green pea. The initial deposits and half‐life of quinalphos were found to be 1.20 mg/kg and 2.77 days, respectively, following the application of insecticide. Residues of quinalphos reached below detection limit of 0.05 mg/kg after 10 days at recommended dosage. For risk assessment studies, the tenth day will be safe for consumers for consumption of green pea. The developed method is simple, selective, and repeatable, and it can be extended for quinalphos‐based standardization of herbal formulations containing green pea and its use in pesticide industries.     

Evaluation of lipid removal from animal fats for the determination of organochlorine, pesticides, and polychlorinated biphenyl indicators by gas chromatography with electron capture detector

For cleanup of animal fat before GC analysis of organochlorine pesticides and polychlorinated biphenyls, freezing-lipid filtration with solid-phase extraction and matrix solid-phase dispersion were evaluated to replace the official Brazilian methodology that uses preparative alumina column chromatography. General drawbacks associated with this last technique, such as the use of large amounts of solvent, laborious and time-consuming procedure could be avoided by using these alternative approaches. Experiments were carried out to study the performance by using different combinations of sorbents and elution solvents. Efficiency of alternative extraction methods in terms of fat removal and recovery capability was monitored by gravimetry, TLC, and GC with electron capture detection. Freezing-lipid filtration with solid-phase extraction afforded better clean up efficiency with recoveries in a range of 54.5 to 103.6% with the relative standard deviation of less than 10% for all compounds under investigation.     

气相色谱-双柱双电子捕获检测器测定土壤及沉积物中23种有机氯农药

建立了微波萃取,弗罗里硅土固相萃取柱及铜粉除硫净化,双柱双电子捕获检测器(ECD)-气相色谱法(GC)测定5种不同质地土壤及5处不同来源沉积物中的23种有机氯农药(OCPs)。采用内标法定量,在0.005～0.5 mg/L的质量浓度范围内,替代物和各种农药标准品的线性相关系数(r2)均大于0.997。5种土壤及5处沉积物中23种OCPs的平均加标回收率分别为50%～119%和52%～120%,相对标准偏差分别为0.9%～16.1%(n=6)和0.3%～28.4%(n=6),检出限为0.00005～0.0005 mg/kg。结果表明,该方法重现性好、灵敏度高、线性关系好,可以满足简便、快速、准确测定农药残留的要求,可大范围推广使用。     

Combining chromatography and chemometrics for the characterization and authentication of fats and oils from triacylglycerol compositional data—A review

The characterization and authentication of fats and oils is a subject of great importance for market and health aspects. Identification and quantification of triacylglycerols in fats and oils can be excellent tools for detecting changes in their composition due to the mixtures of these products. Most of the triacylglycerol species present in either fats or oils could be analyzed and identified by chromatographic methods. However, the natural variability of these samples and the possible presence of adulterants require the application of chemometric pattern recognition methods to facilitate the interpretation of the obtained data. In view of the growing interest in this topic, this paper reviews the literature of the application of exploratory and unsupervised/supervised chemometric methods on chromatographic data, using triacylglycerol composition for the characterization and authentication of several foodstuffs such as olive oil, vegetable oils, animal fats, fish oils, milk and dairy products, cocoa and coffee.