Search

A method based on solid phase extraction (SPE) combined with ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was established for the determination of 24 acid industrial dyes in food. The sample was extracted with ammonia-ethanol solution (ammonia: absolute ethyl alcohol:water=2:7:1, v/v), the extracting solution was condensed to 1 mL under a stream of nitrogen，then dissolved by 10 mL 5% methanol-water solution. The solution was purified by Agela Cleanert PWAX SPE column. The eluant was dried with nitrogen and dissolved by ammonium acetate acetonitrile solution (10 mmol/L ammonium acetate water:acetonitrile =1:1, v/v), the analytes were separated by the Agilent ZORBAX Eclipse RRHD C18 (3.0 mm×150 mm，1.8 μm) column using mobile phase gradient with acetonitrile and 10 mmol/L ammonium acetate. The analytes were ionized with negative electrospray ionization (ESI−) and analyzed by multiple reaction monitoring (MRM) mode, then quantified by external standard method. The linearity of 24 acid industrial dyes displayed good linearities in the range from 20～300 ng/mL, the correlation coefficients higher than 0.999. The limits of detection (LOD) and quantification (LOQ) were 10 μg/kg and 25 μg/kg. The recoveries at three level spiked levels (25、100、250 μg/kg) were 91.0%～112.7% with the relative standard deviations (n=6) between 0.42% and 4.39%. The method was applied to determine 40 batches of bean products, condiments, aquatic products and meat products each, the acid orange Ⅱ was detected in 2 batches of braised meat samples, the content was 138±2.8 μg/kg and 179±3.7 μg/kg, the red 2G was detected in 2 batches of sausage samples, the content was 320±8.6 μg/kg and 230±6.2 μg/kg. The method is rapid, sensitive and reliable, it can be applied to determine 24 acid industrial dyes in food.

Objective: The purpose of this study was to systematically establish a gas chromatography-mass spectrometry (GC-MS/MS) analysis method for polycyclic aromatic hydrocarbons in Spirulina, and empirically analyze the new risk of polycyclic aromatic hydrocarbons found in Spirulina. Method: The polycyclic aromatic hydrocarbons of the sample were extracted twice with n-hexane ultrasonically, purified by QuEChERS, and tested after being concentrated by nitrogen blowing. Qualitative and quantitative: Separation using DB-5 MS capillary chromatographic column, multiple reaction monitoring mode (MRM) combined with matrix-matched external standard method for analysis. Results: The recovery rate was 68.8%～101.9%, the relative standard deviation was 1.8%～8.4% (n=6), the correlation coefficient of the equation reached above 0.999 within the linear range of 1～32 ng/mL, and the limit of quantitative (LOQ) was 2 μg/kg. Polycyclic aromatic hydrocarbons were detected in all 69 commercially available Spirulina samples, with the content in the range of 2.4 μg/kg to 3491 μg/kg. Conclusion: The QuEChERS detection method for 15 polycyclic aromatic hydrocarbons in Spirulina established in this paper is fast, accurate and highly sensitive, and can provide scientific technical support for daily supervision. It is necessary to pay attention to the risk of polycyclic aromatic hydrocarbons in Spirulina products, and further identify the source of pollution to establish prevention and control measures.