摘要
自从水俣病发生以来,人们对环境中汞的含量愈益重视。据报道海水中汞的浓度为0.5—364ngl^(-1),其含量虽如此之微,但为了准确测定不同海域海水中汞含量的自然背景值及评价不同海区水域是否受到汞污染,则要求测定方法具有很高的灵敏度和低的检出限。为了使方法的灵敏度能适应于测定海水中的汞含量,曾采用过预浓缩后进行冷原子吸收测定的方法。
A rapid and extremely sensitive method for the direct determination of mercury concentrations as low as 5 ppt in waters is described.The cell volume(ca.133 ml)being much larger than that of the normal apparatus is one of the characteristics of Model 590 Mercury Vapour Measuring Apparatus.In order to increase and fully utilize the high sensitivity of this apparatus and to lower its detection limit,improvements have been achieved by selecting the optimized plug(the volume of carrier gas which contains mercury is denoted by the plug)cell volume ratio and therefore getting the plug completely into the cell to form a most concentrated mercury plug,and by taking measures to minimize the noise.The optimized measuring parameters such as flow rate,medium effect,reductant amount,shake and equilibrium time have also been investigated.Calibration curve can be made by using a 10‰ NaCl solution instead of sea water free from mercury.With above procedure,for a 250ml sample the concentration detection limit is 5 ppt Hg(Ⅱ)for this apparatus.The relative deviation for 0.03 and 0.2 ppb of inorganic mercury is 6.8% and 3.0% respectively.The time of analysis has been greatly reduced,because the determination is free from preconcentration procedure.Owing to the simplicity of instrumentation Model 590 Mercury Vapour Measuring Apparatus can be used for the direct measurement of sub-ppb levels for both inorganic and total mercury in batches of seawater and natural water samples.The mercury concentration of hundreds of sea water sample has been successively determined by this apparatus with above procedure.
作者
潜琬英
周家义
崔俊芝
王明彪
黄敏芬
Qian Wanying;Zhou Jiayi;Cui Junzhi;Wang Mingbiao;Huang Minfen(Department of Oceanological Chemistry,Shandong College of Oceanology)
出处
《海洋与湖沼》
1978年第2期141-150,共10页
Oceanologia Et Limnologia Sinica
