F. Sánchez Rojas

Derivative ultraviolet-visible region absorption spectrophotometry and its analytical applications.

Theoretical aspects, instrumental devices and analytical applications of derivative ultraviolet-visible region absorption spectrophotometry are reviewed.

Separation and preconcentration by a cloud point extraction procedure for determination of metals: an overview

Recently, cloud point extraction (CPE) has been an attractive subject as an alternative to liquid–liquid extraction. The technique is based on the property of most non-ionic surfactants in aqueous solutions to form micelles and become turbid when heated to the cloud point temperature. This review covers a selection of the literature published on applications of CPE in determination of metal ions over the period between 2004 and 2008.

Recent development in derivative ultraviolet/visible absorption spectrophotometry: 2004–2008: A review

Several techniques have been proposed for treatment of spectrophotometric data, with the objective of extracting a largest amount of analytical information from spectra composed of unresolved bands. Undoubtedly, a major success was achieved by derivative treatment of the absorbance curves-plotting of the first or a higher order mathematical derivative of absorbance against wavelength (d A/d lambda). Derivative spectrophotometry has been applied to many chemical systems, such as pharmaceuticals, foods, cosmetics, and environmental samples. The instrumental development and analytical applications of derivative UV-vis regions absorption spectrophotometry produced in the last 5 years (since 2004) are reviewed.

ReviewRecent development in derivative ultraviolet/visible absorption spectrophotometry: 2004–2008: A review

Several techniques have been proposed for treatment of spectrophotometric data, with the objective of extracting a largest amount of analytical information from spectra composed of unresolved bands. Undoubtedly, a major success was achieved by derivative treatment of the absorbance curves-plotting of the first or a higher order mathematical derivative of absorbance against wavelength (d A/d lambda). Derivative spectrophotometry has been applied to many chemical systems, such as pharmaceuticals, foods, cosmetics, and environmental samples. The instrumental development and analytical applications of derivative UV-vis regions absorption spectrophotometry produced in the last 5 years (since 2004) are reviewed.

Recent developments in derivative ultraviolet/visible absorption spectrophotometery.

The instrumental development and analytical applications of derivative ultraviolet/visible region absorption spectrophotometry produced in the last seven years (since 1987) are reviewed.

Analytical methodologies for the determination of cisplatin.

cis-Diamminedichloroplatinum(II) (cisplatin) is a important chemotherapeutic drug for cancer treatment since 1978. Unfortunately, because of the severe side-effects like nephrotoxicity, ototoxicity, etc., they are administered in small doses at low concentration establishing the maximum limit dosage to 100 mg/m(2) (21 days). A variety of analytical methods have been proposed for the determination of cisplatin in biological fluids and tissues that permit the accurate determination at or below the part per billion level in the native sample. The purpose of the current review is to provide a systematic survey of the latest analytical techniques for the determination of cisplatin in biological samples.

On-line preconcentration of mercury by sorption on an anion-exchange resin loaded with 1,5-bis[(2-pyridyl)-3-sulphophenyl methylene] thiocarbonohydrazide and determination by cold-vapour inductively coupled plasma atomic emission.

Abstract 1,5-Bis[(2-pyridyl)-3-sulphophenyl methylene] thiocarbonohydrazide (PSTH) immobilized on an anion-exchange resin (Dowex) has been used for the on-line preconcentration of mercury from biological samples and waters prior to its determination by inductively coupled plasma atomic emission spectroscopy. The metal was eluted from the column using a solution of 2 M HNO3 and mixed on-line with SnCl2. The optimum experimental conditions were evaluated for the continuous preconcentration of Hg, the direct generation of mercury vapour and the final determination of this element by ICP–AES. The enrichment, together with low blank levels of the optimized procedure, allow the simple determination of this toxic element at concentrations down to a few nanograms per milliliter. The proposed method has a linear calibration range 5–1000 ng ml−1 of mercury, with a detection limit of 4 ng ml−1 (S/N=3) and a sampling rate of 40 h−1, investigated with a 9 ml sample volume. The precision of the method (evaluated as the relative standard deviation obtained after analyzing ten series of ten replicates) was ±3.6% at the 10 ng ml−1 level of Hg(II) and ±1.3% at the 100 ng ml−1 level. The accuracy of the method was examined by the analysis of certified reference materials.

Process Analytical Chemistry: Applications of Near Infrared Spectrometry in Environmental and Food Analysis: An Overview

Abstract This review provides a valuable source of information on the technological advances in near infrared absorption spectrometry area and its industrial applications, especially on the alimentary technology and environmental applications over biofuels.This review provides a valuable source of information on the technological advances in near infrared absorption spectrometry area and its industrial applications, especially on the alimentary technology and environmental applications over biofuels.

Use of flow injection cold vapour generation and preconcentration on silica functionalized with methylthiosalicylate for the determination of mercury in biological samples and sea-water by inductively coupled plasma atomic emission spectrometry

A novel and expeditious approach to the direct determination of mercury in sea-water and biological samples based on a separation–preconcentration system coupled on-line to a flow injection (FI) manifold is described. The method employs on-line preconcentration of mercury on a 3 cm×3 mm column packed with silica gel functionalized with methylthiosalicylate (TS-gel) and placed in the injection valve of the FI manifold. Synthesis of the resin is simpler and faster than that of other resins described previously, where many steps are required. In this system the metal was eluted from the column with thiourea and mixed on-line with NaBH4; mercury vapour was generated directly and separated via a gas–liquid separator. Various parameters and chemical variables affecting the preconcentration of HgII, the direct generation of mercury vapour and the final determination by ICP-AES were evaluated. The calibration graph was linear over the range 5–1000 ng ml–1 HgII, with a relative standard deviation at the 10 ng ml–1 level of 2.1%. The accuracy of the method was evaluated by the analysis of certified reference materials. The results showed good agreement with the certified values.

Automated on-line separation preconcentration system for palladium determination by graphite furnace atomic absorption spectrometry and its application to palladium determination in environmental and food samples

A flow injection (FI) system was used to develop an efficient on-line sorbent extraction preconcentration system for palladium by graphite furnace atomic absorption spectrometry (GFAAS). The investigated metal was preconcentrated on a microcolumn packed with 1,5-bis(di-2-pyridyl)methylene thiocarbohydrazide immobilized on silica gel (DPTH-gel). The palladium is eluted with 40mul of HCl 4M and directly introduced into the graphite furnace. The detection limit for palladium under the optimum conditions was 0.4ngml(-1). This procedure was employed to determine palladium in different samples.