Pulsed amperometric detection of aliphatic alcohols in liquid chromatography

Abstract

The quantitative determination of aliphatic alcohols In liquid chromatography has been hindered by the lack of a sensitive detector. Aliphatic alcohols have no Inherent chromophore or fluorophore and are considered to be electrolnactlve under constant applied potential. The determination of underlvatized aliphatic alcohols by reversed-phase polymer-based chromatography with pulsed amperometric detection (PAD) Is direct, sensitive, and simple. PAD was applied to the determination of simple alcohols at Pt and Au working electrodes under acidic and basic conditions, respectively. The combination of mixed-mode chromatography with a chromophoric (UV-vls) detector and a nonchromophoric detector (PAD) is a powerful analytical technique.

Carbohydrate and alditol analysis by high-performance anion-exchange chromatography coupled with electrochemical detection at a cobalt-modified electrode

“…Figure 4 shows the relevant results obtained in FIA at an applied potential of 0.5 V and using 0.1 mol L -1 NaOH plus different amounts of acetonitrile. In contrast with other common electrode materials, where attenuation of the sensitivity of the amperometric response was observed in mobile phases containing acetonitrile at millimolar levels [29,30], the anodic signals at the GC-Co electrode increased markedly with increasing acetonitrile concentration. In particular, a greatly enhanced amperometric response is observed for sucrose in comparison to that observed for fructose.…”

“…Figure 5 shows the results obtained in FIA at 0.5 V using 0.1 mol L -1 NaOH plus different amounts of methanol. In contrast with other transition metal electrodes where alcohols, and in particular methanol, are easy oxidized [13,30,31,32,33], the GC-Co electrode shows negligible electrocatalytic activity towards alcohol electrooxidation. In fact, as can be seen, the background current exhibited a percentage enhancement of about +10% upon addition of 5% methanol to the sodium hydroxide eluent (0.1 mol L -1 ).…”

Fast determination of naproxen in pharmaceutical formulations by batch injection analysis with pulsed amperometric detection

“…Previous works have demonstrated that pulsed amperometry is able to solve such a drawback by the application of an additional potential pulse for cleaning the electrode surface from adsorbed oxidation products. 21,22 Thus, a sequence of two pulses was studied taking into consideration the detection of naproxen and the efficient electrode cleaning. This strategy resulted in highly repetitive current responses for naproxen injections.…”

“…20 Pulsed amperometry has also been applied to selective determinations of analytes at electrodes that undergo passivation due to adsorption of electrochemically generated oxidation products. 21,22 In the present study, it is reported an application of BIA with pulsed amperometric detection for fast determination of naproxen in pharmaceutical formulations. The application of two potential pulses provided naproxen detection by its electrochemical oxidation (at +1.5 V for 200 ms) without electrode contamination (+1.0 V for 100 ms for electrode cleaning) using an aqueous electrolyte.…”

Development of a Dual‐Band Amperometric Detector for Determination of Ascorbic Acid and Glucose

“…However, a problem usually found when noble metals such as platinum and gold are used as substrate for anodic oxidation of glucose is related to the adsorption of reaction products, which blocks the electrode surface and hinders further oxidation [1]. A strategy that minimizes this problem involves a two-step electrochemical cleaning of the electrode surface by applying a series of potential steps at values where adsorbed material is conveniently removed [2,3]. Another very common approach for glucose sensing is based on the immobilization of an enzyme, usually glucose oxidase, on the electrode surface [4,5].…”