微库仑法测定柴油硫含量条件的优化探讨

对WK-2D型微库仑仪进行调试.从进样量、进样速度、气体流量、炉温4个方面讨论操作因素对微库伦法测定样品硫含量的影响,并确定最优操作条件.在优化条件下,对加标直馏柴油样品进行精密度和回收率考察.结果表明：进样量为1.3μL,进样速度为38档,氮气流量为260 mL/min,氧气流量为150 mL/min,汽化段温度为750℃,燃烧段温度为850℃,稳定段温度为650℃操作条件下测得直馏柴油硫含量误差低,重复性好.加标回收率在99％～102％,RSD＜1％.该方法简单、快速、准确,适合大批量直馏柴油样品的测定.

Study on the conditions optimization of determination of the sulfur content in diesel oil by micro-coulometry

The WK-2D microcoulometer was tuned.The injection volume,injection rate,gas flow rate,furnace temperature,four aspects which impact on the determination of sulfur content of the sample by micro-coulometry were discussed.and the appropriate formula and technologic condition were determined.Under optimization conditions,the precision and recovery rate of straight-run diesel spiked were studied.The results indicated：the injection volume was 1.3μL,injection speed of 38 scale.nitrogen flow 260 mL/min,the oxygen flow 150 mL/min,the vaporization segment temperature of 750 ℃,the combustion segment temperature of 850 ℃,the stable segment temperature of 650 ℃.The method of determination of sulfur content in straight-run diesel oil was reproducible,low error.The recovery was around 99 ％～102 ％ and their RSD values were all lower than 1％.The method was simple,rapidness,accurate and fully suitable for large quantities of determination in the sulfur content of straightrun diesel oil.