Following previous studies on this subject, the use of iodide reagent in acidic medium for the liquid chromatographic amperometric determination of non-volatile nitrosamines has been investigated in a two-line flow-injection manifold coupled with a voltammetric flow-through detector. The peak current signals obtained for the nitrite-iodide reaction were compared with those obtained for the iodate-iodide reaction used as a reference for the production of the electroactive species I−3. The effect of adsorption-desorption phenomena on the reactor walls was investigated and analyzed by the “exponentially modified Gaussian” model applied to flow-injection peaks obtained under different experimental conditions, as to composition of the carrier liquid (water and water-acetonitrile mixtures), concentration of the reagent and temperature of the reactor. From an analytical point of view, the method ensures a satisfactory linear response, a higher sensitivity and a much lower detection limit (about 1 × 10−8 M) than those found with the cerium(IV) reagent, and a comparable band broadening and tailing.
Optimization of the amperometric detection of nitrite by reaction with iodide in a post-column reactor for liquid chromatography of non-volatile nitrosamines
FAVARO, GABRIELLA;PASTORE, PAOLO;
1994
Abstract
Following previous studies on this subject, the use of iodide reagent in acidic medium for the liquid chromatographic amperometric determination of non-volatile nitrosamines has been investigated in a two-line flow-injection manifold coupled with a voltammetric flow-through detector. The peak current signals obtained for the nitrite-iodide reaction were compared with those obtained for the iodate-iodide reaction used as a reference for the production of the electroactive species I−3. The effect of adsorption-desorption phenomena on the reactor walls was investigated and analyzed by the “exponentially modified Gaussian” model applied to flow-injection peaks obtained under different experimental conditions, as to composition of the carrier liquid (water and water-acetonitrile mixtures), concentration of the reagent and temperature of the reactor. From an analytical point of view, the method ensures a satisfactory linear response, a higher sensitivity and a much lower detection limit (about 1 × 10−8 M) than those found with the cerium(IV) reagent, and a comparable band broadening and tailing.
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