HPLC Determination of Naphthalene Amino Derivatives Using Electrochemical Detection at Carbon Paste Electrodes

Abstract

HPLC with electrochemical detection using a carbon paste electrode based on glassy carbon spherical microparticles with an organic pasting liquid has been used for the determination of trace amounts of carcinogenic 1-naphthylamine, 2-naphthylamine, 1,5-diaminonaphthalene and 1,8-diaminonaphthalene. The lowest limit of detection found was 5.4 Â 10 À9 mol L À1 for 1,5-diaminonaphthalene. The limits of detection for the above analytes using the electrochemical detection with a carbon paste electrode were in all cases lower than the corresponding limits of detection for the spectrophotometric detection. The newly developed method of determination was verified on model samples of drinking and river water.

Nontraditional Electrode Materials in Environmental Analysis of Biologically Active Organic Compounds

“…Wall-jet carbon paste detectors in HPLC enable the whole day work in a mixed water-organic modifier media with the only renewal of the electrode surface at the beginning of the day while the relative standard deviations are very low, even around 1% for 10 to 20 consecutive injections [50 -53]. It was also shown that the distance of the outlet capillary from the wall-jet surface is not critical [50], [53]. The signals did not changed markedly with the distance from 1 (sensor in the contact with outlet capillary) to 5 mm [52] (see Fig.…”

“…Carbon pastes based on classical spectrographic carbon powders and paraffin, silicon or mineral oils as binders were used in the past predominantly in aqueous media or mixed media with low amounts of organic modifiers as higher content of, e.g., methanol or acetonitrile quickly degraded the pastes which limited their use as electrochemical detectors in HPLC. The introduction of globular particles [48] and glassy carbon spherical microparticles [49] resulted in more stable pastes and the construction of simple wall-jet carbon paste electrochemical detector which could be used in HPLC and FIA [50]. The comparison of repeatability of measurements using carbon electrodes or composite carbon electrodes and carbon paste electrodes or sensors favors solid electrodes, on condition that proper and sometimes time demanding surface renewal is applied.…”

“…The modification of carbon paste with cyclodextrin enabled to decrease L Q of carcinogenic polycyclic aromatic amines to nanomolar region [68], the same was valid for the determination of 1-aminopyrene and 1-hydroxypyrene [69] where the carbon paste was modified either by cyclodextrins or by DNA. Nanomolar concentrations (the lowest L Q % 5.4 Â 10 À9 mol L À1 of 1,5-diaminonaphthalene) were reached for HPLC-ED determination of amino-and diaminonaphthalenes using CPE [50].…”

Carbon paste electrodes in the new millennium

“…One of such criteria can be the size of electrode and, in this respect, carbon paste ultramicroelectrodes (CPUMEs) reported by Nyokong et al [142] are certainly exceptional, when the respective ensembles were tested in two configurations: as (i) CP-disc-shaped electrode (with overall diameter ∅ CP = 100-150 μm), and ® -machined body and of ordinary size (authors' own construction); (ii) prototype of a small CPE as the exchangeable working electrode for wall-jet HPLC detector; (iii 1+2 ) two carbon paste mini-electrodes of slightly different surface size (via cut tip); (iv 1+2 ) two assembled carbon paste groove electrodes; set-up for a detection unit in FIA-mode (right) and the electrically heated variant (left) connected to a thermometer (above). (For further specification, see original reports [141,[143][144][145][146]. )…”

“…A simple construction of the latter is shown on Fig. 1, together with a prototype of small CPE-holder that has been designed recently to be used as exchangeable working electrode in a wall-jet detector for HPLC [144]. For comparison, the image illustrates a third piston-driven CP-holder [141], representing an older type of CPE with ordinary size.…”