新型在线自动监测仪测定地表水中的痕量锑

Determination of Trace Antimony in Surface Water by a New On-line Automatic Monitoring Instrument

锑是湘江上游永州部分区域的特征重金属污染因子,利用在线自动监测仪准确测定地表水中锑的含量,为精准助力锑污染预警与防控具有重要意义。基于2-(5-溴-2-吡啶偶氮)-5-二乙氨基酚(5-Br-PADAP)分光光度法,优化建立了在线自动监测仪测定地表水中痕量锑的方法。采用新型在线自动监测仪自动采样、进样、预处理,在萃取剂用量2 mL、萃取时间40 min、萃取温度40℃、搅拌速度500 r/min、萃取溶剂(苯)与介质(盐酸)配比1∶6等优化条件下进行液液自动微萃取,在光照度500 lm/m^(2)等条件下通过高灵敏微型光电传感模块自动测定地表水中的锑。测定结果表明,萃取剂用量小于2 mL、检出限低至1μg/L、线性误差小于2.5%、相对误差小于5%、加标回收率88.2%~104%、相对标准偏差小于2%、量程漂移小于2%。建立的方法萃取剂用量少、检出限低、线性度和稳定性好、准确度和精密度高,能连续准确、在线自动、实时监测地表水中的痕量锑。

Antimony is a characteristic heavy metal pollution factor in some areas of Yongzhou in the upper reaches of the Xiangjiang river.The on-line automatic monitoringinstrument was used to accurately determine the content of antimony in surface water is of great significance for accurate antimony pollution warning and prevention.Based on the 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol(5-BR-PADAP)spectrophotometric method,a method for the determination of trace antimony in surface water by on-line automatic monitor was optimized and established.The liquid-liquid automatic microextraction was carried out using a new online automatic monitoring instrument for automatic sampling,injection,and pre-processing.The corresponding optimized conditions were as follows:the dosage of extractant 2 mL,extraction time of 40 minutes,extraction temperature of 40℃,agitation speed of 500 r/min,and extraction solvent(benzene)to medium(hydrochloric acid)ratio of 1∶6.antimony in surface water was automatically determined by a high sensitive micro-photoelectric sensor under the conditions such as illumination of 500 lm/m^(2).The results showed that the extraction amount of the new online automatic antimony monitoring instrument developed in this paper was less than 2 mL,the detection limit was as low as 1μg/L,the linear error,the relative error,the precision range and span drift were less than 2.5%,5%,2%and 2%,respectively.The corresponding standard recovery was 88.2%-104%.The method has the advantages of low extractant dosage,low detection limit,good linearity and stability,high accuracy and precision,and can continuously,accurately,online automatically,and real-time monitoring the trace antimony content in surface water accurately and continuously.