Niaz Abdul, Shah Afzal, Bhanger Muhammad Iqbal, Saeed Munawar, Jamali Mohammad Khan, Arain Mohammad Balal
National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, Sindh 76080, Pakistan.
Talanta. 2008 Feb 15;74(5):1608-14. doi: 10.1016/j.talanta.2007.10.010. Epub 2007 Oct 13.
A new simple sensitive differential pulse polarographic (DPP) method was investigated for the determination of acrylamide (AA) directly in a neutral aqueous solution. The AA showed a well-defined and well-resolved peak in pure aqueous LiCl at -1.84V in the potential range from -1.6V to -1.97V at nitrogen pressure of 0.5kgcm(-2). Among the various electrolytes studied, the AA showed good DPP response in the presence of LiCl and tetra methyl ammonium iodide, while it showed poor response in the presence of tetra butyl ammonium hydroxide and tetra butyl ammonium bromide due to their strong adsorption on the surface of electrode which hindered its reduction. The effect of LiCl concentration, the cyclic voltammetric response and the drop time study showed that AA exhibited an irreversible adsorptive electrochemical behavior. The good electrochemical response in pure aqueous medium suggested that hydrogen bonding might be involved which may favor the electrode reaction. Under optimized conditions, the peak current was linear in the entire concentration range from 0.2 mgL(-1) to 20 mgL(-1) with the correlation coefficient of R(2)=0.9998. The method showed good reproducible results with R.S.D. of 0.3% (n=16). The detection limit (LOD) was 27 microgL(-1). The influence of various interfering agents was also studied. The method was applied successfully for the quantification of AA in water samples without any interference effect from alkali metals.
研究了一种新型简单灵敏的差分脉冲极谱法(DPP),用于直接测定中性水溶液中的丙烯酰胺(AA)。在0.5kg/cm²氮气压力下,AA在纯LiCl水溶液中于-1.84V处,在-1.6V至-1.97V的电位范围内显示出清晰且分辨率良好的峰。在所研究的各种电解质中,AA在LiCl和四甲基碘化铵存在下显示出良好的DPP响应,而在四丁基氢氧化铵和四丁基溴化铵存在下显示出较差的响应,这是因为它们在电极表面强烈吸附,阻碍了AA的还原。LiCl浓度的影响、循环伏安响应和滴汞时间研究表明,AA表现出不可逆的吸附电化学行为。在纯水介质中的良好电化学响应表明可能涉及氢键,这可能有利于电极反应。在优化条件下,峰电流在0.2mg/L至20mg/L的整个浓度范围内呈线性,相关系数R² = 0.9998。该方法具有良好的重现性,相对标准偏差为0.3%(n = 16)。检测限(LOD)为27μg/L。还研究了各种干扰剂的影响。该方法成功应用于水样中AA的定量分析,不受碱金属的干扰。