称取一定量已切碎、捣碎并混匀的酸菜样品用硝酸及过氧化氢先在90 ℃水浴中消解约20 min,然后将溶液冷却,移入微波消解仪中消解。消解完毕后将溶液冷至室温,移入25 mL容量瓶中,加入50 g·L-1硫脲-50 g·L-1抗坏血酸混合溶液5 mL,加水定容。在所选定的仪器条件下用14 g·L-1硼氢化钾溶液作还原剂生成砷的氢化物进行测定。砷的质量浓度在10.00 μg·L-1以内与相应的荧光强度值呈线性关系。方法的检出限(3s/k)为0.064 μg·L-1,测得方法的回收率在89.0%~102.5%之间,测定值的相对标准偏差(n=6)为1.7%。

The sample of sauer kraut was pretreated by slicing, crushing and homogenizing. A definite quantity of the homogeneous sample was taken and digested with conc. HNO3 and H2O2 firstly at 90 ℃ in a water bath for ca. 20 min, then after cooling, digested in the microwave digestor. After completion of digestion, the solution was cooled to room temperature and transferred to a 25 mL volumetric flask, 5 mL of mixed solution of 50 g·L-1 thiourea solution and 50 g·L-1 ascorbic acid solution were added, and then diluted to mark with water. Arsenic was determined in the sample solution by AFS under the optimized instrumental condition with addition of 14 g·L-1 KBH4 solution as reductant for generation of AsH3. Linear relationship between values of fluorescence intensity and mass concentration of arsenic was found in the range with 10 μg·L-1, with detection limit (3s/k) of 0.064 μg·L-1. Recovery and precision of the method were tested, giving results of recovery ranged from 89.0% to 102.5%, and RSD (n=6) of 1.7%.