Kester M D, Shiundu P M, Wade A P
Laboratory for Automated Chemical Analysis, Department of Chemistry, University of British Columbia, Vancouver, B.C., Canada, V6T 1Z1.
Talanta. 1992 Mar;39(3):299-312. doi: 10.1016/0039-9140(92)80036-d.
A manual colorimetric method for determination of sulfide has been adapted to flow injection, systematically optimized, and more fully characterized. Its intended application is for measurement of sodium sulfide reagent strength in pulp process streams, and sulfide contamination in effluent from Kraft pulp mills. In the flow-injection method developed, a sample solution containing sulfide is reacted with a mixture of iron(III) and nitrilotriacetic acid under ammoniacal conditions. The absorbance of the intensely-colored green product of this reaction is measured at 636 nm. Excess sulfite is present as a color stabilizer. A linear dynamic range of 20-100 ppm sulfide is readily achieved; the relative standard deviation is less than 1.2% (n = 10) throughout this range, and 0.37% (n = 10) midrange at 60 ppm. The usable dynamic range is 8-250 ppm sulfide. Long-term stability of the method is ensured by periodically performing an automatic cleaning cycle using a hydrochloric acid wash solution. This prevents tube discoloration and removes any precipitates which are formed under strongly alkaline conditions. The sample throuhput rate is at least 30/hr, given alternate acid wash cycles.
一种用于测定硫化物的手动比色法已被应用于流动注射分析，进行了系统优化并得到更全面的表征。其预期应用是测量制浆工艺流中硫化钠试剂的强度以及硫酸盐制浆厂废水中的硫化物污染。在开发的流动注射法中，含硫化物的样品溶液在氨性条件下与铁（III）和次氮基三乙酸的混合物反应。在636nm处测量该反应产生的深绿色产物的吸光度。过量的亚硫酸盐用作颜色稳定剂。硫化物的线性动态范围很容易达到20 - 100ppm；在整个该范围内相对标准偏差小于1.2%（n = 10），在60ppm的中间范围为0.37%（n = 10）。可用动态范围为8 - 250ppm硫化物。通过定期使用盐酸洗涤溶液进行自动清洗循环来确保该方法的长期稳定性。这可防止管道变色并去除在强碱性条件下形成的任何沉淀物。在交替进行酸洗循环的情况下，样品通量率至少为每小时30个。
