碱熔-离子色谱法测定土壤中全硫的研究

Determination of total sulfur in soil by alkali fusion ion chromatography

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1h,使土壤中各种形态的硫转化为SO42-,冷却,用水超声浸提。离子色谱法测定。分析柱AS14A4-mm(4mm×250mm),淋洗液0.008mol·L-1Na2CO3、0.001mol·L-1NaHCO3,再生液0.05mol·LH2SO4-1,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0.8mg·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。

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 Na2CO3/0.001 mol·L^-1 NaHCO3 and regenerant was0.05 mol·L^-1H2SO4. 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 standard 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.