Search

A method for determining human epidermal growth factor (hEGF) in cosmetics was developed using solid-phase extraction with high-performance liquid chromatography – tandem mass spectrometry. The sample was extracted and purified by a mixed anionic solid-phase extraction column (MAX), and the eluent was passed through a nylon filter membrane into a polypropylene vial. The matrix-matched external standard method was used to quantify the analyte in multi-reaction monitoring mode. The analyte had an excellent peak shape within 11 min with a linear range from 5 to 80 ng/mL and a linear correlation coefficient (r) of 0.9995. The limit of detection and limit of quantification were 0.75 and 2.5 μg/kg, respectively. The recovery of the target was from 81.5% to 88.8%, and the relative standard deviation was between 1.16% and 5.07%. The results met the International Organization for Standardization 12787 standard. The established method was successfully applied to 30 cosmetic samples. The proposed method is sensitive, accurate, reliable, and suitable for the quantitative confirmation of hEGF and monitoring its illegal addition to cosmetics. [ABSTRACT FROM AUTHOR]

A simple, rapid and sensitive method for the determination of aflatoxins in peanut oil was developed using MIL-101(Cr) material filled syringe filter for one-step solid-phase extraction (SPE) with high-performance liquid chromatography—tandem mass spectrometry (HPLC-MS/MS) detection. The MIL-101(Cr) sorbent was characterized and its mass, the loading solution, and the eluent were optimized; under these conditions, a matrix matching internal standard method was developed. The linear range was from 0.1 to 20 ng/mL with correlation coefficient (r) exceeding 0.9998. The recoveries were between 94.7% and 105.9% with relative standard deviations from 2.02% 6.88%. The recoveries of inter-day and intra-day measurements were from 93.0% to 98.5% and 97.6% to 100.7%. The precision values for inter-day and intra-day analyses were from 6.09% to 7.68% and 2.56% to 4.30%, respectively. The pretreatment efficiency of the developed method was superior to literature procedures and used to determine aflatoxins in 126 peanut oil samples from local markets. 38 samples had positive results and 1 sample exceeded the allowable limit. Hence, the developed protocol was suitable for the determination of aflatoxins in peanut oil. [ABSTRACT FROM AUTHOR]