[Fabrication of conventional ion chromatography-capacitively coupled contactless conductivity detector]

A conventional ion chromatography-capacitively coupled contactless conductivity detector (IC-C⁴D) was fabricated. The main parameters, such as the electrode length and gap, tube material and inner diameter, excitation frequency, voltage and waveforms, were optimized. The self-made C⁴D showed comparable performance to that of a commercial contact conductivity detector. Under the suppressed mode, the limits of detection of common inorganic anions (F^-, Cl^-, NO₂^-, Br^-, NO₃^-, and SO₄^2-) were 0.02-0.08 μmol/L. The relative standard deviations (RSDs) for the peak area were less than 1.8% (n=6). The linearities of the six common inorganic anions were achieved in the range of 0.1-10 μmol/L with correlation coefficients (R²)>0.9950. The advantages of such a C⁴D in a relatively conventional mode include simple structure, low fabrication cost and no electrode fouling, and it will help extend the application of IC.