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

Abstract 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) – 100 mM acetic acid (AcOH) and 50 mM NaOH (pH 4.6); detection wavelength – 200 nm for An + and 254 nm for Py + ; vacuum injection period – 15 s (190 nL); SIT generation – 10 kV applied for 80 s with the sample inlet side anode; separation voltage – 20 kV with the sample inlet side anode. The limits of detection (LODs, S/N = 3) of An + and Py + respectively reached 10 and 42 μg/L, with good repeatability (peak area RSDs ≤ 6.9%) and calibration graph linearity ( R 2  = 0.9997). The proposed method was applied for determination of An + and Py + in sewage samples. Recoveries of An + (0.50 mg/L) and Py + (2.0 mg/L) in spiked sewage samples were 94–104%.