不同物质对铬价态测定结果的影响

采用单波长法和双波长法,分别考察了KH2PO4、H3PO4、H2SO4、KNO3、牛肉膏和蛋白胨对Cr(III)和Cr(VI)质量浓度测定的影响。结果显示,Cr(III)和Cr(VI)在测量中是相互影响的,并且Cr(III)对Cr(VI)影响较显著。在单波长法测定中,牛肉膏、蛋白胨及2种酸对Cr(III)和Cr(VI)的影响较钾盐对其影响更为显著,H3PO4和H2SO4对Cr(III)和Cr(VI)的特征吸收峰值影响最大,降低幅度在20%～50%。这些物质对双波长法测定Cr(VI)几乎没有影响;但对Cr(III)测定中,H2SO4和H3PO4的影响较大,其相对误差分别为14.57%和8.87%,其余物质产生的相对误差均小于1.6%。因此,双波长法可用于生物样品中Cr(III)和Cr(VI)的测定,线性范围分别为0～160 mg/L和0～80mg/L。

Effects of different materials on the results of determining chromium valence

The present paper aims to introduce the effects of different materials on the results of determining chromium valence by using the latest development findings in bioremediation,e.g.the redox of microorganism on heavy metals.However,the cultivation components of microorganism usually involve a certain interference in determining the heavy metal valence.In order to find a simple,quick and accurate determining method that can help to detect the content of Cr(III) and Cr(VI) in the biological samples,we have taken as testing materials and experimental methods the single wavelength UV-VIS scanning method,the double-wavelength method,along with six kinds of basic components and standard chromium solutions.In addition,we have also investigated the effects of KH2PO4,H3PO4,H2SO4,KNO3,beef extract and peptone on the determination of Cr(III) and Cr(VI).The results of our experiments and measurements show that the effects of Cr(III) and Cr(VI) are mutual in nature.Just like the absorption spectra of the mixture of Cr(III) and Cr(VI),the absorption peaks of Cr(III) and Cr(VI) tends to be the highest and strongly affect the Cr(VI) determination.Therefore,as compared with potassium salts,beef extract,peptone,H3PO4 and H2SO4 have the strongest effect on the determination of the characteristic absorption peaks of Cr(III) and Cr(VI) in single wavelength testing.However,since H3PO4 and H2SO4 significantly influence the absorption intensity of the characteristic absorption peak of Cr(III) and Cr(VI),the drop range would be likely to reach 20% to 50%.However,relative errors can also take place at a rate between 14.57% to 8.87%,which can be produced by the rest of the material at a rate of less than 1.6% due to the influence of H2SO4 and H3PO4.And,consequently,dual-wavelength method can be applied to the measurement of Cr(III) and Cr(VI) in biological samples,with the linear range being 0-160 mg/L and 0-80 mg/L,respectively.