采用微波等离子体原子发射光谱法,以氩气为工作气体和载气,氧气为屏蔽气,测定了交联淀粉中磷含量.试验表明:测试溶液的酸度应保持在0.03 mol·L-1以下,且预先将样品充分洗涤,除去共存的钠离子.在最佳试验条件下测定了磷的检出限、精密度、加标回收率.结果表明:波长为253.565 nm的分析谱线具有最高的灵敏度;载气和工作气为氩气,流量分别为1.5,0.27 L·min-1时,分析线253.565 nm的强度最高.测得磷的检出限(3S/N)为0.02 μg·L-1.此方法测得结果的准确度和精密度与电感耦合等离子体原子发射光谱法相当,而从节能和降低成本方面考虑此方法有更好的应用前景.

Phosphorus in cross-linked starch sample was determined by microwave plasma torch (MPT)-AES,using argon as the working and carrier gas and oxygen as the shielding gas.It was shown that acidity of testing sample solution should be kept below 0.03 mol·L-1,and that co-existing Na+-ion should be removed from the starch sample by washing to eliminate its interference.Under the optimized conditions,it was found that highest sensitivity and intensity were attained by choosing the analytical spectral line of 253.565 nm,and by working at the flowrate of 1.5 and 0.27 L·min-1 for the carrier gas and working gas.Detection limit (3S/N) found for the method was 0.02 μg·L-1.By parallel analysis of cross-linked starch sample for its phosphours content by the present method and by ICP-AES,consistent analytical results and values of RSD′s (n=5) were obtained.It was proved that the MPT-AES was feasible to be used for less energy consumption and lower operation cost as compared with ICP-AES.