碱熔-离子色谱法测定土壤中全硫的研究

研究了用碱熔-离子色谱法测定土壤中全硫的方法,样品采用氧化镁—碳酸钠(2:1)混合熔剂,在恒温马弗炉中800℃加热1 h,使土壤中各种形态的硫转化为SO_4~(2-),冷却,用水超声浸提.离子色谱法测定.分析柱AS14A4-mm(4 mm×250mm),淋洗液0.008mol·L~(-1)Na_2CO_3、0.001 mol·L~(-1)INaHCO_3,再生液0.05mol·LH_2SO_4~(-1),流量1.0mL·min~(-1),进样体积20μL,外标峰面积定量.该方法测定土壤中硫检测限为0.8 mg·kg~(-1),在测量浓度范围内具有良好的线性关系.用该方法做精密度,相对标准偏差为3.91%.与不同地区的标准土做对比实验,所测结果跟标准值相比均在标准值范围内.实验证明该方法操作简便、快速.

Determination of total sulfur in soil by alkali fusion ion chromatography

A determination method of total sulfur in soil by alkali fusion ion chromatography was investigated. Samples mixed with magnesium oxide and sodium carbonate (2 : 1) in a muffle furnace at 800 ℃ for 1 h, making all the sulfur present as sulfurate, added some water and extracted by the ultrasonic assistant extraction. The determination of sulfurate were achieved on AS14A 4-mm(4 mm×250 mm) column with eluent as 0.008 mol·L~(-1) Na_2CO_3/0.001 mol·L~(-1) NaHCO_3 and regenerant was0.05 mol·L~(-1)H_2SO_4. The determination was performed at a flow rate of 1.0 mL·min~(-1), the injection volume was 20 μL, and the use of area-external stan-dard method to measure their amount. The detection limit of this method was 0.8 mg·kg~(-1). The RSD was3.91% in the determination of precision .The data from the determination of standard soils from different district were all in the predict range. It is proved that this method is simple and fast.