对苯二胺荧光探针测定水质样品中的溶解态汞

Determination Mercury in Water Samples by P-phenylenediamine as Fluorescent Probe

为获得水质样品中的溶解态汞简便、灵敏的测定方法,以含有荧光基团和氨基活性基团的对苯二胺作为荧光探针,基于其荧光猝灭程度与Hg(Ⅱ)浓度呈线性关系,建立了荧光光度法测定水质样品中溶解态汞的检测方法。考察了缓冲体系的类型、pH值、浓度以及荧光探针的浓度等条件,确定采用pH=5.0的HAc-NaAc缓冲溶液(0.010 mol/L)体系和0.40μg/mL的对苯二胺荧光探针的荧光探针实验条件,并应用于实际水质样品中。结果表明,当Hg(Ⅱ)浓度在0.64~1.36μg/mL,荧光探针对苯二胺的荧光淬灭程度与Hg(Ⅱ)浓度成良好的线性关系(R=0.9991),重复性实验的相对标准偏差为0.72%,方法检出限为0.032μg/mL,加标回收率均在96.2%~105%。方法简便、灵敏度高、选择性好,可用于实际水质样品中溶解态汞的测定,具有较好的应用前景。

In order to obtain a simple and sensitive method for the determination of dissolved mercury in water samples,p-phenylenediamine containing fluorescent groups and amino active groups was used as a fluorescent probe.Based on the linear relationship between the fluorescence quenching degree and the concentration of Hg(Ⅱ),a fluorophotometric method for the determination of dissolved mercury in water samples was established.The type,pH value,concentration of buffer system and the concentration of fluorescent probe were investigated.HAc-NaAc buffer solution(0.010 mol/L)with pH=5.0 and 0.40μg/mL p-phenylenediamine fluorescent probe were determined and applied to the actual water quality samples.The results indicated that the degree of fluorescence quenching of 0.40μg/mL p-phenylenediamine had a good linear relationship with 0.64-1.36μg/mL mercury ion at pH 5.0(0.010 mol/L acetic acid buffer solution).The RSD and LOD of mercury ion were 0.72%and 0.032μg/mL,respectively,and the spiked recoveries were in the range of 96.2%-105%.The method is simple,sensitive and selective,and can be used for the determination of dissolved mercury in water samplesin the future.