分光光度法测定水产品中的二甲胺

Spectrophotometry detection of dimethylamine in aquatic products

建立了分光光度法测定水产品中二甲胺(dimethylamine,DMA)含量的方法。水产样品中的DMA用三氯乙酸提取、与铜铵试剂反应显色后用苯萃取,用分光光度计在波长434 nm测定吸光度值,根据标准曲线计算样品中二甲胺的含量。结果表明:反应体系在pH 12.0、50℃水浴时间3 min下显色良好,DMA浓度在0~10 mg/L内具有良好的线性关系,回归方程为y=0.057 4x-0.005 7(R^2=0.999 7),检出限为6 mg/kg。选用6种不同品种的水产品作加标回收率试验,其加标回收率为86.7%~99.2%,相对标准偏差为1.36%~4.78%。

A method for determining dimethylamine （DMA） in aquatic products was established using spectro- photometry. The DMA in aquatic products was extracted by TCA, after color reaction with copper-amine, it was then extracted by benzene. The absorbance of DMA colorimetric solution at 434 nm; the content of DMA was calculated based on the DMA standard curve. The results shows that：the color was kept well under pH 12.0 and water bath at 50℃ for 3 rain. Under the optimal conditions,the standard curve was linear in the range of 0 - 15 mg/L for DMA with a detection limit of 6 mg/kg, the regression equation of the concentration（x） and the absorbance （y） of DMA was y = 0. 057 4x - 0. 005 7 and correlation coefficient was R^2 = 0. 999 7. The average recoveries for DMA at three spike lev- els for six different kinds of aquatic products were in the ranges of 86.7% -99.2% ,with relative standard deviations （RSD） of 1.36% -4.78%. Therefore,this method is simple, and the result is reproducible and sensitive. Therefore, it is suitable for common laboratory usage.