The rapid quantitative analysis of three pesticides in cherry tomatoes and red grape samples with Tchebichef image moments.

Diverse interferences often affect the determination of pesticide residues in various kinds of food, and complex pretreatments are necessary. An effective approach for the simultaneous quantitative analysis of multi-target components in different substrates was proposed, and applied to the determination of ternary pesticides in cherry tomatoes and red grape samples. By means of HPLC-DAD, the spectra were obtained under isocratic elution. Utilizing the Tchebichef image moments, unified quantitative models were established for the three target components in the samples with two different substrates, respectively. The correlation coefficients of leave-one-out cross-validation (Rloo-cv2) of the obtained models were more than 0.9975. The predictive correlation coefficients (Rp2) were more than 0.9831. Compared with the N-PLS and MCR-ALS methods, the proposed approach is not only more accurate and reliable, but also can extract essential information and expected to be a potential tool to rapidly quantify multi-component in different substrates without complex pretreatments.

Analysis of binding properties and interaction of thiabendazole and its metabolite with human serum albumin via multiple spectroscopic methods.

Thiabendazole (TBZ), which is oxidized into 5-hydroxythiabendazole (5-OH-TBZ) in vivo, is a commonly used food preservative. Interactions of TBZ and 5-OH-TBZ with human serum albumin (HSA) were comprehensively studied via multiple spectroscopic methods and molecular docking. This study focussed on the mechanistic and structural information on binding of TBZ and 5-OH-TBZ to HSA to evaluate the impact of the food additive on HSA. 1H NMR spectra of the two ligands showed the binding exists. ITC and fluorescence spectroscopy results revealed that TBZ was a stronger ligand, with a binding constant of 105l/mol and formed a more stable complex with HSA than did 5-OH-TBZ via electrostatic interaction. Spectroscopic results (UV-vis, FT-IR, and CD) showed that TBZ and 5-OH-TBZ caused conformational changes in HSA, in which α-helix and ß-turn transformed into ß-sheet, causing HSA structure to loosen. Docking programs showed that both TBZ and 5-OH-TBZ bound to HSA via IB.

Simultaneous determination of plant growth regulator and pesticides in bean sprouts by liquid chromatography-tandem mass spectrometry.

A simple and sensitive analytical method based on QuEChERS approach using liquid chromatography tandem mass spectrometry was developed and validated for the determination of 6-benzylaminopurine, carbendazim and thiabendazole in bean sprouts. Sodium chloride and sodium acetate were used for salting-out step and magnesium sulfate for clean-up. The validation of optimized method was satisfactory with recoveries, between 89.5% and 103.2% for the three compounds, and relative standard deviation (RSD) values less than 3.3% at 20 and 40ng/g fortification levels (n=5). Limit of detection (LOD) and limit of quantification (LOQ) was 2.1-3.7ng/g and 6.3-11.1ng/g, respectively. Monitoring of 126 bean sprout samples collected from local markets was performed to verify the adaptability in real samples. No pesticides were detected but 6-benzylaminopurine was found in 3 samples at the level of 15-20ng/g. The optimized method should be applicable for monitoring of 6-benzylaminopurine, carbendazim and thiabendazole in bean sprouts in short time.