Simultaneous determination of fluorescent whitening agents (FWAs) and photoinitiators (PIs) in food packaging coated paper products by the UPLC-MS/MS method using ESI positive and negative switching modes was written by Wu, Zhijiang;Xu, Yansheng;Li, Mianchang;Guo, Xindong;Xian, Yanping;Dong, Hao. And the article was included in Analytical Methods in 2016.Application of 7128-64-5 This article mentions the following:
A sensitive ultra-high performance liquid chromatog. tandem mass spectrometry (UPLC-MS/MS) method was established for the simultaneous determination of fluorescent whitening agents (FWAs) and photoinitiators (PIs) in food packaging coated paper products. Samples were firstly soaked in water and then ultrasonically extracted by using methanol-trichloromethane. The extraction solution was subsequently separated by using a Phenomenex Luna C18 (2) chromatog. column (50 mm × 2.00 mm, 3 μm) using methanol-5 mmol L-1 ammonium acetate as the mobile phase. The target analytes were ionized by the ESI pos. and neg. switching modes and detected using the multiple-reaction monitoring (MRM) mode. The method was validated for linearity and range, accuracy, precision and sensitivity. Under the optimized conditions, the calibration curves were linear over the selected concentration ranges of 10-1000 μg L-1 and 0.5-50 μg L-1 for four FWAs (FWA28, FWA85, FWA71 and FWA351) and the rest of the ten compounds, resp., with calculated coefficients of determination (R2) greater than 0.99. The instrument limit of quantitation (ILOQ) and the corresponding method limit of quantitation (MLOQ) of fourteen target analytes were in the range of 0.5-10 μg L-1 and 6-125 μg kg-1, resp. Recoveries were calculated at three levels of concentration spiked into neg. samples and the values were found between 79.2% and 115% with relative standard deviation (RSD) values of 3.2-12.3% for intra-day precision (n = 6) and 4.5-11.5% for inter-day precision (n = 5) 2.5-7.2%. The method was successfully applied to analyze twenty-five food packaging coated paper product samples and FWA184 and 4-MBP were detected in only two samples with the concentrations of 151 μg kg-1 and 32 μg kg-1, resp. In the experiment, the researchers used many compounds, for example, 2,5-Bis(5-(tert-butyl)benzo[d]oxazol-2-yl)thiophene (cas: 7128-64-5Application of 7128-64-5).
2,5-Bis(5-(tert-butyl)benzo[d]oxazol-2-yl)thiophene (cas: 7128-64-5) belongs to benzothiophene derivatives. Benzothiophene is a fused ring compound of thiophene ring and benzene ring, which is an important class of heterocycles with advantageous structures. Its aromaticity makes it relatively stable, although as a heterocycle, it has reactive sites which allow for functionalization.Application of 7128-64-5
Referemce:
Benzothiophene – Wikipedia,
Benzothiophene | C8H6S – PubChem