毛细管电泳场放大进样-高压非接触电导检测测定痕量Zn~(2+)

利用高压电容耦合非接触电导检测器(HV-C4D),结合毛细管电泳场放大进样(FASS),以2-N-吗啡啉乙磺酸(MES)/组氨酸(His)为缓冲溶液,电泳分离测定了Zn2+.考察了样品溶液中MES/His的浓度及电动进样时间对场放大浓缩因子及缓冲溶液浓度对检测灵敏度的影响.在10mmol/LMES/His(pH=4.9)的分离缓冲溶液中,FASS对Zn2+的浓缩因子为1.3×103.Zn2+的浓度在10～1000nmol/L范围内与峰面积有良好线性关系(R=0.9995),检测限为5nmol/L(S/N=3).该方法可用于痕量Zn2+的测定.

Determination of Trace Zn2+ by Capillary Electrophoresis with Field-amplified Sample Injection and High Voltage Contactless Conductivity Detection

Analysis of trace Zn2+ by capillary electrophoresis with field-amplified sample stacking(FASS) and high voltage capacitively coupled contactless conductivity detection(C4D) was presented. 2-(N-Morpholino) ethanesulfonic acid(MES)/histidine(His) was used as the separation electrolyte. The effects of MES/His concentration in the sample matrix, and the injection time on the effective stacking efficiency, and the concentration of the separation electrolyte on the sensitivity were studied. Zn2+ was dissolved in deionized water and separated in 10 mmol/L MES/His(pH=4.9) buffer. The C4D using FASS yielded sensitivity enhancement with respect to non-stacking injection mode in excess of three orders of magnitude(1.3×103) and a limit of detection(LOD) 5 nmol/L to Zn2+. There was a linear relationship between the response of peak area and concentration of Zn2+ in the range from 10 to 1 000 nmol/L(R=0.999 5). The method can be used for determination of Zn2+ of trace level.