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研究了痕量锰形态分析的水解分离-原子吸收光谱法。依据不同价态锰水解酸度的不同,使以各种形态存在的锰彼此分离以对其进行AAS测定。用NaOH溶液调试样的pH到10,此时以MnO4-形式存在的高价锰不产生水解沉淀,而低价Mn(Ⅱ)和中价Mn(Ⅳ)产生水解沉淀,对清液中的Mn(Ⅶ)进行AAS测定;然后用pH为5的硫酸溶液溶解沉淀,此条件下Mn(Ⅱ)的沉淀溶解,从而使Mn(Ⅱ)和Mn(Ⅳ)彼此分离,对清液中的Mn(Ⅱ)进行AAS测定;最后,用pH为1的硫酸溶液溶解Mn(Ⅳ),并沉淀进行AAS测定。从上述测定,可分别求得Mn(Ⅱ),Mn(Ⅳ)和Mn(Ⅶ)含量。该方法的加标回收率分别在93.3%~99.5%,96.7%~103%和98.2%~104%之间,相对标准偏差分别为2.7%,3.2%和3.1%,检出限为0.10mg.L-1,该法简单,快速,准确。
Hydrolytic Separation - Atomic Absorption Spectrometry for Trace Manganese Speciation Analysis. According to different valence manganese hydrolysis acidity difference, the various forms of manganese are separated from each other for their AAS determination. NaOH solution was used to adjust the pH of the sample to 10, at this time, MnO4- exists in the form of high-manganese does not produce hydrolytic precipitation, while the low price of Mn (II) and the price of Mn (IV) produce precipitation, the clear liquid Mn Ⅶ) .After that, the precipitates were dissolved by sulfuric acid solution of pH 5, and the precipitate of Mn (Ⅱ) was dissolved to separate Mn (Ⅱ) and Mn (Ⅳ) from each other. ); Finally, Mn (IV) was dissolved in a sulfuric acid solution of pH 1 and precipitated for AAS measurement. From the above determination, the contents of Mn (II), Mn (IV) and Mn (VII) can be obtained respectively. The recoveries of the method were 93.3% -99.5%, 96.7% -103% and 98.2% -104%, respectively. The relative standard deviations were 2.7%, 3.2% and 3.1%, respectively. The detection limit was 0.10 mg. L-1, the method is simple, fast and accurate.