Abstract: The design, construction and operation are described of a spectroelectrochemical detector, with a 1 cm optical path length, that incorporates an optically transparent reticular vitreous-carbon working electrode (cf. Dewald and Wang, Anal. Chim. Acta, 1984, 166, 163) which can easily be replaced in the event of electrode fouling. In the determination of [Fe(CN)6]3- by a flow injection procedure, with spectrophotometry at 410 nm, the calibration graph was rectilinear in the range 4 to 100 µM and the limit of detection was ~2 µM. Application of the detector in LC is exemplified by the analysis of a mixture of phenol, chlorophenols and nitrophenols. A spectroelectrochemical detector for flow injection and liquid chromatography is described. The detector design has dimensions of a standard 1 cm sample cuvette with a replaceable reticulated vitreous carbon working electrode. No special cell holder or modifications to the spectrophotometer are required to use the detector. Chronocoulometry is used to indicate a trend from thin-layer behavior toward semi-infinite diffusion behavior as the electrode pore size increases. Ferro-/ferricyanide solutions were used to evaluate the flow injection characteristics of the detector. A sampling rate of 180 injections per h was used. Linear calibration curves in the micromolar range were achieved with a reproducibility of 2-7%. A mixture of phenol, chlorophenols, and nitrophenols was used to investigate the simultaneous electrochemistry and optical response for liquid chromatography

Abstract: The cited electrode was prepared by fixing a cellulose triacetate dialysis membrane to the end of a vitreous C electrode. The Hg film was deposited on the electrode from an acidified mercury(II) nitrate solution (details given). The electrode was incorporated in a wall-jet flow cell (diagram given) and used for the determination of Pb in various samples. Water and urine were acidified with 0.5 M HNO3. Blood (10 µL) was diluted (1:29) with 5% HCl or Metexchange M reagent. A 190 µL portion of the resulting solution was injected into a carrier stream (1.1 ml/min) of 10 mM KNO3/10 mM HNO3 and transported to the wall-jet cell. Pb was determined by Osteryoung square-wave anodic-stripping voltammetry (OSWASV) or by potentiometric-stripping analysis (PSA; details given). The flow was stopped during the deposition and stripping cycles. OSWASV was applied to water: the calibration graph was linear up to 1000 ppb of Pb; RSD (n = 8) were 1.7-6%. PSA was applied to all the samples: for water and urine, RSD (n = 8) were 3-5.4%. For blood, the calibration graph was linear up to 60 ppb of Pb; the detection limit was 2.7 ppb; RSD (n = 8) were 5.3-10.6%.