Capillary zone electrophoresis determination of aniline and pyridine in sewage samples using transient isotachophoresis with a system-induced terminator.

Transient isotachophoresis (tITP) with a system-induced terminator (SIT) was developed for capillary zone electrophoresis (CZE) determination of aniline (An+ ) and pyridine (Py+ ) in sewage samples. After sample injection, a water vial was set at the sample-inlet side. Then voltage was applied to generate a system-induced terminator (H+ ). Experiments and simulations revealed a concentration effect by tITP with an SIT: background electrolyte (BGE) - 100mM acetic acid (AcOH) and 50mM NaOH (pH 4.6); detection wavelength - 200nm for An+ and 254nm for Py+ ; vacuum injection period - 15s (190nL); SIT generation - 10kV applied for 80s with the sample inlet side anode; separation voltage - 20kV with the sample inlet side anode. The limits of detection (LODs, S/N=3) of An+ and Py+ respectively reached 10 and 42μg/L, with good repeatability (peak area RSDs≤6.9%) and calibration graph linearity (R2 =0.9997). The proposed method was applied for determination of An+ and Py+ in sewage samples. Recoveries of An+ (0.50mg/L) and Py+ (2.0mg/L) in spiked sewage samples were 94-104%.