流动注射在线共沉淀HG-AFS测定痕量铅

Determination of trace Pb by flow injection on-line co-precipitation hydride g eneration atomic fluorescence spectrometry

建立了流动注射在线共沉淀HG AFS测定痕量铅的分析方法。方法基于铅在碱性介质中与氢氧化镁共沉淀,沉淀收集在锥形沉淀腔中,用HCl溶洗沉淀和NaBH4反应,产生的氢化物被载气引入原子化器中进行测定。测定铅的RSD为3%(5ng mL,n=10),检出限为0.01ng。检出限较直接进样降低了11倍。对国家标准物质中铅的测定结果与标准值相符。

A flow injection on-line co-precipitation technique for the pre-conce ntration of trace amount of Pb2+ with the precipitate of Mg(OH)2 as carr ier was reported. The co-precipitation was carried out in NaOH medi um and the precipitate was collected in a precipitation collector. The precipita te was then dissolved by HCl and reacted with NaBH4. The hydride was transferr e d directly into the atomizer. Pb was then determined by AFS. The relative standa rd deviation was 3% for 10 deter mination of 5 ng/mL and the detection limit was 0.01 ng/g. The method was applied to the determination of trace Pb in geosamples with satis factory results.