title: Determination of anions using monolithic capillary column ion chromatography with end-to-end differential contactless conductometric detectors under resonance approach.
abstract: An end-to-end differential measurement approach with capacitively coupled contactless conductivity detection (C(4)D) was applied to anion-exchange monolithic capillary column ion chromatography. The column was prepared by thermally initiated radical polymerization of poly(glycidyl methacrylate) in a fused-silica capillary of 320 μm i.d. and modified by quaternary ammonium latex surface coating. Two C(4)Ds were placed near both ends of the capillary column and the output difference between them was measured. With 15 mM potassium hydrogen phthalate used as the eluent, good separation of a mixture of inorganic anions (F(-), Cl(-), NO(2)(-), NO(3)(-)) was achieved. The detection limits of conventional C(4)D are 1.6, 0.28, 0.53, and 0.47 mg L(-1) for F(-), Cl(-), NO(2)(-), and NO(3)(-), respectively. To further enhance the sensitivity, the capacitive impedance from C(4)D was neutralized by an inductive impedance from a piezoelectric resonator. An increase in sensitivity by a factor of 7-8 was achieved in the resonating C(4)D in comparison with the conventional C(4)D. The detection limits of the resonating C(4)D are 0.23, 0.041, 0.065, and 0.059 mg L(-1) for F(-), Cl(-), NO(2)(-), and NO(3)(-), respectively. The response of the resonating C(4)D was analyzed based on an equivalent circuit model.
authors.affiliation: The Key Lab in Molecular and Nano-materials Probes of the Ministry of Education of China, College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan, 250014, PR China.
authors.forename: Zhenli
authors.initials: Z
authors.lastname: Zhang
authors.forename: Dongdong
authors.initials: D
authors.lastname: Li
authors.forename: Xueyong
authors.initials: X
authors.lastname: Liu
authors.forename: Qamar
authors.initials: Q
authors.lastname: Subhani
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhu
authors.forename: Qi
authors.initials: Q
authors.lastname: Kang
authors.forename: Dazhong
authors.initials: D
authors.lastname: Shen
mesh_terms: D000838:Anions / Q000032:analysis / Q000737:chemistry; D002852:Chromatography, Ion Exchange / Q000295:instrumentation / Q000379:methods*; D004553:Electric Conductivity; D004566:Electrodes; D011891:Rain / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D000838:Anions; D014867:Water