悬浮液进样GFAAS法测定食用明胶中的铬

Determination of Chromium in Edible Gelatin by GFAAS with Suspension Sample

为建立悬浮液直接进样-石墨炉原子吸收光谱法(graphite furnace atomic absorption spectrophotometry,GFAAS)测定食用明胶中铬的方法,研究配置悬浮液过程中,明胶颗粒大小,表面活性剂的用量以及取样量与定容体积比对检测结果的影响。讨论基体改进剂的选择,优化石墨炉原子吸收光谱仪的升温程序。研究表明,不必加入表面活性剂,当定容体积为10 mL时,称取0.30 g^0.35 g粒径小于0.15 mm的明胶颗粒所配置的悬浮液最适于检测。选择硝酸镁作为基体改进剂,仪器最佳检测条件为灰化温度1 500 ℃,原子化温度2 200 ℃。在此条件下,方法检出限为0.001 mg/kg,试验的相对标准偏差在5 %以下,加标回收率在95 %到115 %之间。该方法能够简单、有效并快速地进行食用明胶中铬的检测。

The graphite furnace atomic absorption spectrophotometry (GFAAS) coupled with the suspension injection method was established to determine the chromium in the edible gelatin. During suspension preparing, the effects of gelatin particle size, the amount of surfactant, and the ratio of sample weight to constant volume on the detection results were studied. The choice of matrix modifier was discussed, the heating program of GFAAS was optimized. The studies showed that addition of a surfactant was not necessary, when the constant volume was 10 mL, the suspension prepared by weighing 0.30 g-0.35 g gelatin with particle size less than 0.15 mm was most suitable for detection. Magnesium nitrate was selected as the matrix modifier, the optimal detection condition of GFAAS with the ashing temperature of 1 500 ℃ and atomization temperature of 2 200 ℃. Under the optimal conditions, the method detection limit was 0.001 mg/kg, the relative standard deviation of the test was less than 5 %, the recoveries were between 95 % and 115 %. The method was simple, effective and rapid for the determination of chromium in edible gelatin.