摘要
研究利用显色剂邻二氮菲分析铁价态时存在的问题。结果显示,在铁的价态分析中,Fe(Ⅲ)的存在,会使显色剂直接分光光度法高估Fe(Ⅱ)的浓度。采用掩蔽剂可以很好地解决这一问题,EDTA和NH4F掩蔽法干扰Fe(Ⅱ)的测定,比较适合的Fe(Ⅲ)掩蔽剂为NTA。显色剂直接分光法适用范围较窄,当总铁中的Fe(Ⅲ)含量≥52%时,方法相对误差较大,变得不稳定,而总铁中的Fe(Ⅲ)含量≤90%时,NTA掩蔽法即可使用,拓宽了铁价态分析的适用范围。应用2种控制图证明,双波长法和还原法测定总铁均无系统误差,但还原法极差和相对误差均较小,方法更准确可靠。
In the present work,the reliable spectrometric determination of Fe（Ⅱ） and total iron was investigated by using the 1,10-Phenanthroline.The results indicated that co-existed Fe（Ⅲ） resulted in the overestimation of Fe（Ⅱ）,howerer,complexing agent can solve this problem.Because of interference for Fe （Ⅱ）,NTA is prefered rather than EDTA and NH4F.Whenever Fe（Ⅲ） accounts for more than 52%,relative error for traditional o-phenanthroline method is out of control.NTA modified o-phenanthroline method was superior to original o-phenanthroline method,which is insensitive to Fe（Ⅲ） up to a point where Fe （Ⅲ） might be as high as 90% total iron.A statistical analysis demonstrated,Harvey’s method and method based reduction reaction can determinate total iron and a statistical analysis demonstrated significant evidence of systematic error dose not exsit.what’ more,the latter was reliable owning to smaller range and relative error.
出处
《食品科技》
CAS
北大核心
2013年第5期285-289,共5页
Food Science and Technology
关键词
Fe(Ⅲ)
Fe(Ⅱ)
掩蔽剂
邻二氮菲
ferrous iron
ferric iron
complexing agent
1,10-phenanthroline
