用空气-乙炔火焰原子吸收光谱法测定润滑油中的钙和钡

Determination of Ca and Ba in Lubicating Oil by Air-Acetyene Flame Atomic Absorption Spectrometry

为了提高空气－乙炔火焰的原子化效率．本法对选用的增感剂作了系统的研究，确定了用十二烷基磺酸钠和苄基三甲基氯化铵为混合增感剂，达到与联邦德国标准ＤＩＮ５１３９１Ｔ１和英国标准ＩＰ３０８的同等水平。而它们都以氧化亚氮－乙炔为原子化气 体． 本试验将两种火焰原子化作了对比。在氧化亚氮－乙炔火焰中，Ｂａ的变动系数为０．９％～１．９％；Ｃａ、为 １．１％～１．９％：在空气－乙炔火焰中，Ｂａ的变动系数为１．２％～２．５％，Ｃａ为１．１％～３．０％。通过系列的比较，本法的重复误差小于ＤＩＮ和ＩＰ３０８规定的误差。４８对样品的实测结果．６３％小于ＤＩＮ规定的重复性之半 （２．５％）．

Calcium and barium are present in lubricating oils as additives. The method of determinating Ca and Ba usually used both at home and abroad is the nitrous oxide-acetylene flame method. In this paper a method using air- acetylene flame is developed For the sake of increasing the atomizing efficiency of the air-acetylene flame, a systematic investigation on the enhancing agents has been made. It was found that sodium dodecy1 sulfonate and benzyl trimethy1 ammonium chloride mixture as enhancing agent gives the best result. By means of this mixed enhancing agents in air-acetylene flame atomic absorption, Ca and Ba can be determined with accuracy satisfying the requirement of the West German Standard DIN-51391T.1 and British IP 308, while in these standards nitrous oxide-acetylene is used for atomization. Comparison is made between the atomization using nitrous oxide-acetylene and air-acetylene flame, In the former case, the variation coefficient for Ba is 0.9%~1. 9%, for Ca is 1.1% ~1.9%. In the latter case , the variation coefficient for Ba is 1.2%~2.5%, that for Ca is 1.1% ~3.0%. Through corn-parision it has been found that the method proposed by this paper gives. a better reproducibility with a standard error below that method according to DIN and IP308. From the results of the analyses of 48 pairs of samples, 63% of them give a reproducibility below half of the standard error stipulated by DIN.