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.

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 developments in analytical determination of furosemide.

Furosemide (FUR), a drug that promotes urine excretion, is used in the pharmacotherapy of various diseases and is considered as a doping agent in sports. FUR is a powerful diuretic (water pill). This medicine is used to treat excessive fluid accumulation and swelling (edema) of the body caused by heart failure, cirrhosis, chronic kidney failure, and nephrotic syndrome. Owing to its extensive use as a powerful diuretic, FUR has long attracted the attention of many analysts. A variety of analytical methods have been proposed for the determination of FUR in biological fluids and pharmaceutical samples. The revision includes the most relevant analytical methodologies used in its determination from the nineties decade at present.

Analytical methodologies for the determination of omeprazole: an overview.

Omeprazole, a gastric acid pump inhibitor, dose-dependently controls gastric acid secretion; the drug has greater antisecretory activity than histamine H(2)-receptor antagonists. Omeprazole has been determined in formulations and biological fluids by a variety of methods such as spectrophotometry, high-performance liquid chromatography with ultraviolet detection and liquid chromatography coupled with tandem mass spectrometry. The overview includes the most relevant analytical methodologies used in its determination since the origin still today.

An ion-exchange method for speciation of antimony by flow injection electrothermal atomic absorption spectrometry.

In this work, a simple preconcentration system, achieved by replacing the sample tip of the autosampler arm by a micro-column packed with Amberlite IRA-910 or silica gel chelating resin functionalised with 1,5-bis(di-2-pyridyl)methylene tbiocarbohydrazide (DPTH-gel), is developed for the determination of Sb(V) and total antimony, respectively. Different factors including pH of sample solution, ionic strength, concentration and volume of eluent, sample flow rate, sample loading time and matrix effects for preconcentration were investigated. The method has been applied to the determination of antimony species in different samples.

Determination of paracetamol: historical evolution.

Paracetamol is a common analgesic and antipyretic drug that is used for the relief of fever, headaches and other minor aches and pains. Their determination in pharmaceuticals is of paramount importance, since an overdose of paracetamol can cause fulminating hepatic necrosis and other toxic effects. Many analytical methodologies have been proposed for the determination of paracetamol. The aim of the present study is to evaluate the utility of different techniques for quantification of paracetamol content in pharmaceutical formulations and biological samples.

Separation preconcentration method for platinum and rhodium from environmental samples using a chelating resin.

A method of determining trace levels of platinum and rhodium in different samples was investigated. The method involves separation and preconcentration of the platinum and rhodium from the matrix by flow injection (FI) on-line coupled with electrothermal atomic absorption spectrometry (ETAAS) with Zeeman effect background correction. Platinum and rhodium were adsorbed on a microcolumn packed with 1,5-bis(di-2-pyridyl)methylene thiocarbohydrazide immobilized on silica gel (DPTH-gel). The sorbed metals were directly eluted with nitric acid into the graphite furnace and determined by AAS.

Determination of rhodium: Since the origins until today Atomic absorption spectrometry.

Rhodium is present at about 0.001ppm in the earths crust. Rhodium metal is known for its stability in corrosive environments, physical beauty and unique physical and chemical properties. Recent interest in the medical and industrial significance of platinum and to a lesser extent palladium and rhodium has been accompanied by an increasing interest in their determination at low levels. Platinum group elements (PGEs: Pt, Pd, Rh, Ru, Ir and Os) play a decisive role in the performance of catalytic converters, world-wide applied in vehicles and in some household utensils, to reduce the emission of gaseous pollutants, such as carbon monoxide, nitrogen oxides and hydrocarbons. Since then, approximately 73% of the world production of rhodium is consumed in the production of autocatalyst. However, the hot exhaust gases flowing through the converter cause abrasion of these units, leading to the emission of these elements to the environment. The concentration level of rhodium (also platinum and palladium) is still very low in the nature; accordingly, their determination in environmental samples specially appears to be a challenging task for analytical chemists. In recent years, the development of analytical methods for the determination of rhodium has increased. The aim of the present review is to evaluate the utility of atomic absorption spectrometry, applied for the quantification of rhodium in different materials, such as environmental, biological, metallurgical and geological samples.

Use of 1,5-bis(di-2-pyridyl)methylene thiocarbohydrazide immobilized on silica gel for automated preconcentration and selective determination of antimony(III) by flow-injection electrothermal atomic absorption spectrometry.

Selective sorption of Sb(III) on a microcolumn packed with 1,5-bis(di-2-pyridyl)methylene thiocarbohydrazide immobilized on silica gel (DPTH-gel) has been used for determination of Sb(III). A flow-injection system comprising a microcolumn connected to the tip of the autosampler was used for preconcentration. The sorbed antimony was eluted with nitric acid directly into the graphite furnace and determined by AAS. The detection limit for antimony under the optimum conditions was 0.3 ng mL(-1). This procedure was used for determination of antimony in natural water, soil, vegetation, and a certified sample of a city waste incineration ash (BCR 176).

Effluent analysis in analytical chemistry: an overview.

This review summarizes and discusses effluent analysis, focusing on the methods and techniques that have been most frequently described in the literature since 1975. The methods are classified into four main categories: (1) physical and chemical properties; (2) inorganic metals analysis; (3) inorganic non-metallic analysis; (4) organic analysis.

On-line preconcentration of rhodium on an anion-exchange resin loaded with 1,5-bis(2-pyridyl)-3-sulphophenyl methylene thiocarbonohydrazide and its determination in environmental samples.

A method for the determination of rhodium in different samples at trace levels is presented. The investigated metal is preconcentrated on a chelating resin microcolumn (1,5-bis(2-pyridyl)-3-sulphophenyl methylene thiocarbonohydrazide (PSTH) immobilized on an anion-exchange resin (Dowex 1x8-200)) placed in the autosampler arm. The modification of the autosampler in the tubing line and circuit allowed either the flow of the sample through the column or the operation of the autosampler in the normal mode, where microlitres of 4M HNO(3), which acts as the elution agent, pass through the microcolumn eluting Rh(III), which is directly deposited in the graphite tube as drop of a precisely defined volume. The detection limit is 0.3ngml(-1). Linearity is maintained in the concentration range 0-50ngml(-1) for rhodium, with correlation factor of 0.999 and relative standard deviation of 1.8% for 10ngml(-1) of Rh. The effects of various parameters such as pH, concentration and volume of eluent, sample loading time, sample flow rate and interference of a large number of metal ions and anions on the determination of this metal was studied in detail to optimize the conditions for their determination in various samples. The method is found to be highly selective, fairly sensitive, simple, rapid and economical and may be safely applied to their determination in different complex materials such as environmental samples and catalysts.

On-line ion-exchange preconcentration and determination of traces of platinum by electrothermal atomic absorption spectrometry.

A method to determine trace amounts of platinum in different samples based on electrothermal atomic absorption spectrometry is described. The preconcentration step is performed on a chelating resin microcolumn [1,5-bis(2-pyridyl)-3-sulfophenyl methylene thiocarbonohydrazide (PSTH) immobilized on an anion-exchange resin (Dowex 1x8-200)] placed in the autosampler arm. The combination of a peristaltic pump for sample loading and the atomic absorption spectrometer pumps for elution through a selection valve simplifies the hardware. The peristaltic pump and the selection valve are easily controlled electronically with two switches placed in the autosampler, which are activated when the autosampler arm is down. Thus, the process is fully automated without any modification of the software of the atomic absorption spectrometer. Under the optimum conditions with a 60-s preconcentration time, a sample flow rate of 2.4 mL min(-1), and an injection volume of eluent of 40 microL, a linear calibration graph was obtained in the range 0-100 ng mL(-1). The enrichment factor was 14. The detection limit under these conditions is 1 ng mL(-1), and the relative standard deviation (RSD) is 1.6% for 10 ng mL(-1) of Pt. The method has been applied to the determination of platinum in catalyst, vegetation, soil, and natural water samples. The results showed good agreement with the certified value and the recoveries of Pt added to samples were 98-105%.

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.

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 HNO(3) and mixed on-line with SnCl(2). 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.