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In‐line coupling capillary electrochromatography with amperometric detection for analysis of explosive compounds
Author(s) -
Hilmi Abdelkader,
Luong John H. T.
Publication year - 2000
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/(sici)1522-2683(20000401)21:7<1395::aid-elps1395>3.0.co;2-c
Subject(s) - amperometry , chromatography , chemistry , capillary electrochromatography , detection limit , analytical chemistry (journal) , methanol , sodium dodecyl sulfate , explosive material , capillary electrophoresis , electrode , electrochemistry , organic chemistry
Amperometric detection at a bare gold electrode has been in‐line coupled with capillary electrochromatography (CEC) for analysis of nitroaromatic and nitroamine explosives in contaminated soils and ground water. The CEC column packed with 3 μm C18 particles performed best using a mobile phase containing 70—80% methanol, 30 or 20% water, 5 m M sodium dodecyl sulfate (SDS) and 10m M 2‐( N ‐morpholino)ethanesulfonic acid (MES). In contrast, the separation column packed with 1.5 μm C18 particles exhibited the best separation when only 30% methanol was added to a mobile phase containing 70% water, 7 m M SDS, and 10 m M MES. The detection, based on electrochemical reduction of the explosives (−0.7 or −1 V vs. Ag/AgCl, depending upon the level of methanol in the mobile phase), was compatible with such mobile phases. The detection limits for 13 explosives ranged from 100 to 200 ppb, i.e. , about twofold better than those obtained with electrokinetic chromatography (EKC)/amperometric detection. From an operational viewpoint, exhaustive column conditioning was a prerequisite and care should be taken to prevent bubble formation and current breakdown during the course of separation. The CEC column equipped with amperometric detection successfully measured explosives in ground water and extracts prepared from contaminated soils and the results obtained agreed well with those of the U.S. Environmental protection Agency (EPA) method.