色谱自动进样瓶可溶出砷对样品砷形态测定的影响

Arsenic sample contamination through the use of glass autosampler vials

选用几种常用玻璃色谱自动进样瓶(简称色谱瓶),包括硼硅玻璃、一级水解级玻璃和高白料玻璃色谱瓶,以及聚丙烯材质的色谱瓶,1%HNO3对色谱瓶浸提后用ICP-MS和HPLC-ICP-MS测定浸提液中砷的总量和形态,并研究了10%HNO3对色谱瓶的清洗效果;此外还探讨了温度及时间对玻璃色谱瓶中砷释放的影响.结果表明,玻璃色谱瓶中砷普遍存在,其中硼硅玻璃色谱瓶浸提液中砷浓度低于1μg·L-1,用10%HNO3酸泡24 h能够全部清除;而一级水解级玻璃和高白料玻璃色谱瓶浸提液中砷的浓度则高达45.67μg·L-1和70.25μg·L-1,酸泡24 h后也有较高的残留量,浓度分别为1.63μg·L-1和0.94μg·L-1.高温能促进玻璃色谱瓶中砷的释放;玻璃色谱瓶中砷的释放量随时间的延长而增加,但短时间内即达到平衡.形态分析结果表明,玻璃色谱瓶浸提液中砷形态为As(Ⅴ),没有检测到As(Ⅲ)、二甲基砷酸(DMA)和甲基砷酸(MMA).同时,聚丙烯色谱瓶浸提液中砷总量低于检测限,因而在进行砷形态测定时,建议使用聚丙烯色谱瓶或者经10%HNO3清洗后的硼硅玻璃色谱瓶,以避免玻璃色谱瓶中As(Ⅴ)的污染.

Arsenic （As） speciation is a key establishing the environmental guidelines. factor in understanding its biogeochemical behavior as well as The hyphenation of HPLC and ICP-MS is a powerful technique for As species determination. However, since As is often used as a clarifier agent in glass melting practice, As leaching from the glass autosampler vials may contaminate samples during the As species determination. Therefore, three types of glass autosampler vials, including borosilicate glass, 1＂ hydrolytic glass and high white material glass and one type of polypropylene autosampler vials, were chosen to investigate As concentration and species in the 1% HNO3 leachate with ICP-MS and HPLC-ICP-MS, so as to understand the As release from the glass autosampler vials and find ways to avoid the contamination. In addition, vials were cleaned by using 10% HNO3 and the cleaning efficiency was measured. Moreover, effects of high temperature （ 80 ~C ） and leaching time on As leaching from glass autosampler vials were also tested. The results showed that As concentration in the leachate of polypropylene vials was below the limit of detection, while the leachates of all the 3 glass vials contained different As concentrations. Arsenic concentrations in the leachates of borosilicate glass vials were below 1 p,g.L-1, which was eliminated by immersing the vials in 10% HNO3 for 24 h. However, the As concentrations in the leachates of 1 s, hydrolytic glass vials and high white material glass vials were 45.67 μg . L-1 and 70.25 μg .L-1, respectively, and remained at 1.63 μg . L-1 and 0.94 μg. L- 1 even after the acid wash. High temperature treatment increased As concentration in the leachate of glass autosampler vials, and As leaching from the vials was a time-dependent process and the release reached the maximum in a short time. The As speciation results indicated that As （V） was the only species in the leachates of the glass vials. Therefore, polypropylene vials or 10% HNO3 immersed borosilicate glass vials are the best choices in As species determination.