湿式消化-ICP-AES法测定航空润滑油中镍钛镁铬钼锡

ICP-AES DETERMINATION OF NICKEL, TITANIUM, MAGNESIUM, CHROMIUM, MOLYBDENUM AND STANNUM IN AVIATION LUBRICATING OIL BY WET DIGESTION OF SAMPLES

研究采用硝酸-高氯酸混合酸湿式消化法,建立ICP-AES法同时测定航空润滑油中痕量金属元素镍、钛、镁、铬、钼、锡。样品消化完全、快速,检出限分别为(μg.L-1):镍4.1、钛2.1、镁4.2、铬3.2、钼3.6、锡24.4,RSD小于5%,回收率为96.0%~104.0%。

Conditions of wet digestion of the oil samples with acid mixture were studied, and the process of repeated digestion of 1~2 g of sample with conc. HNO_3 and finally fuming with mixed acid of HNO_3 and HClO_4((3+1)) was chosen for the pretreatment of oil sample. A slightly yellow or colorless solution was obtained and transferred to a 25 mL volumetric flask and diluted to mark with water, which was used as the mother solution for the ICP-AES determination. By this wet-digestion treatment, the organic matters were completely oxidized and decomposed, thus, eliminating the matrix interference effectively. The optimum working conditions of the ICP-AES determination of the above mentioned metal ions were described in detail. The values of detection limit (3S_b/K) of the six element were found to be (gL^(-1)): Ni 4.1, Ti 2.1, Mg 4.2, Cr 3.2, Mo 3.6 and Sn 24.4. Recoveries obtained by standard addition method were in the range of 96.0% to 104.0%. RSDs found for these elements in analysis of oil sample were less than 5%.