基于非接触电导检测和在线富集技术快速灵敏检测土壤中速效磷  

Rapid and Sensitive Determination of Available Phosphorus in Soil by Capillary Electrophoresis with On-line Preconcentration and Contactless Conductivity Detection

作　　者：齐培杉 朱蓬生 谢天尧[1] QI Pei-shan;ZHU Pen-sheng;XIE Tian-yao(School of Chemistry,Sun Yat-sen University,Guangzhou 510275,China)

机构地区：[1]中山大学化学学院,广东广州510275

出　　处：《分析测试学报》2022年第5期787-791,共5页Journal of Instrumental Analysis

基　　金：产学研项目(2018PLR028)。

摘　　要：针对土壤中速效磷的快速检测需求,建立了基于非接触电导检测和场放大进样在线富集技术的毛细管电泳分离检测土壤中水溶性磷酸盐的分析方法。对影响分离检测效果的实验条件(电泳运行液组成、pH值、分离电压、进样电压和时间)进行了考察和优化。采用毛细管区带电泳模式,以35 mmol/L乙酸-2 mmol/L乙酸铵溶液为电泳运行液,负高压分离(-14 kV)和场放大进样(-11 kV×10 s),磷酸根离子在8 min内可获良好分离和灵敏检测,检出限为5μg/L,线性范围为16~800μg/L。研究表明放大进样在线富集技术使检测灵敏度得到显著提高,富集因子可达580倍。日内和日间相对标准偏差(RSD)小于5.0%。土壤中共存的常见无机阴离子(Cl^(-)、SO^(2)_(4)-、NO^(-)_(3))、有机基质和浸出液基体颜色不干扰速效磷的测定,表现出较强的抗干扰能力。该方法无需复杂的前处理即可直接进样分析,具有简单快速、灵敏高效、分析成本低的优点。对实际土壤样品和国标土壤样品中的速效磷进行检测,检测结果与标准方法一致。A new method for the rapid separation and sensitive determination of available phosphorus in soil by capillary electrophoresis(CE)with field-amplified sample injection(FASI)and capactively coupled contactless conductivity detection(C4D)was developed.Parameters affecting the CE separation and FASI efficiency were investigated in detail,including the composition and pH value of running buffer solution,separation voltage,sample injection voltage and time.The analyte was well separated and sensitively detected within 8 min in a fused-silica capillary under the optimum conditions of 35 mmol/L acetic acid-2 mmol/L ammonium acetate as running buffer,with separation voltage of-14 kV,electrokinetic injection of-11 kV×10 s.The calibration curve showed good linearity in the range of 16-800μg/L,with a limit of detection of 5μg/L.As a result,FASI showed significant increase of sensitivity with an enhancement factor of 580.The intra-and inter-relative standard deviations(RSD)were below 5.0%.The co-existed inorganic anion(Cl^(-),SO^(2)_(4)-,NO^(-)_(3))and organic acid did not interfere with the detection of available phosphorus in soil.Contents of available phosphorus in soil samples could be easily determined without complex sample pretreatment.This proposed method could meet the requirements for the fast screening and sensitive detection of available phosphorus in soil samples.

关 键 词：非接触电导检测 场放大进样 在线富集技术 毛细管电泳 速效磷 土壤 

分 类 号：O657.1[理学—分析化学] Q613.62[理学—化学]