Application of QuEChERS-based purification coupled with isotope dilution gas chromatography-mass spectrometry method for the determination of N-nitrosamines in soy sauce

Abstract

A sensitive and rapid method involving an improved approach called the quick, easy, cheap, effective, rugged, and safe (QuEChERS) purification method and isotope dilution gas chromatography-mass spectrometry (GC-MS) was established to determine six N-nitrosamines (NAs) in soy sauce. Samples were firstly extracted by ethyl acetate. Then the extraction solution was concentrated by slow nitrogen gas blowing and subsequently purified using the QuEChERS-based purification method. Separation of six target NAs was performed on an INNOWAX polar capillary chromatographic column. All of the samples were detected by selected ion monitoring (SIM) mode of GC-MS and N-nitrosodimethylamine-d 6 (NDMA-d 6 ) and N-nitrosodipropylamine-d 14 (NDPA-d 14 ) were used as internal standards. The developed method was validated in terms of the linearity, limit of detection (LOD), matrix effects, specificity, accuracy and precision. Results indicated that this method is of good specificity with almost negligible matrix effects. Linear relations of six NAs were favourable in the range of 2.0-200 mg L À1 and the correlation coefficients were greater than 0.9994. The LODs were lower than 1 mg kg À1 (0.4-0.9 mg kg À1 ) and the limits of quantitation (LOQs) of the method were within the range of 1.2-3.0 mg kg À1 . The mean recoveries for negative light and dark soy sauce samples at three spiked concentration levels were in the range of 80.2-112% with overall relative standard deviation (RSD) values (n ¼ 6) of 2.5-6.8%. The validated method was simple and rapid, with good repeatability, and was successfully applied to determine the concentrations of NAs in soy sauce.

Simultaneous determination of twelve mycotoxins in edible oil, soy sauce and bean sauce by PRiME HLB solid phase extraction combined with HPLC-Orbitrap HRMS

“…The matrix effect (ME) was evaluated by the ratio of the two with reference to the standard solution of the same concentration prepared by pure solvent, that is, the formula ME = B/A, where A and B represent the peak areas of analytes in pure solvent and blank sample matrix solution, respectively. If ME < 0.8, it indicates that the matrix has a significant inhibition on the response of analytes; if ME > 1.2, it indicates that the matrix will significantly enhance the response of analytes; if 0.8 ≤ ME ≤ 1.2, it indicates that the matrix effect is not significant ( 23 , 32 ). The experimental results are shown in Figure 3 .…”

Method Development and Validation of Indaziflam and Its Five Metabolites in Soil, Water, and Fruits by Modified QuEChERS and UHPLC-MS/MS

“…The most effective solvent for extracting the samples therefore needed to identified. MeCN, ethyl acetate, and n -hexane are frequently used to extract samples when determining pesticide residues. − We therefore compared the recoveries achieved using MeCN, ethyl acetate, and n -hexane to extract the samples. As shown in Figure , taking orange as an example, the ethyl acetate gave low IND-diam (<35%) and IND-olef (<40%) recoveries, but satisfactory recoveries of the other analytes.…”

Determination of halquinol residual levels in animal‐derived food products using liquid chromatography–tandem mass spectrometry

“…Limits of detection (LOD) and quantitation (LOQ) were determined using spiked samples (free from halquinol) that were extracted and quantified as described in Section 2. LOD and LOQ values were calculated as 3 and 10 times the signal‐to‐noise ratio, respectively (Zeng, Bai, Xian, Dong, & Luo, ). As shown in Table , the LODs and LOQs were 3 and 5 μg/kg for 5,7‐dichloroquinolin‐8‐ol and 4 and 10 μg/kg for 5‐chloroquinolin‐8‐ol.…”