Search results for " absorption spectroscopy"

Chemical characterization of iron in atmospheric aerosols

1992

Abstract The total Fe content, the soluble fractions of Fe(II) and Fe(III), and several species of Fe were determined in various atmospheric aerosol samples by means of atomic absorption spectrometry, ion chromatography and Mossbauer spectrometry.

Atomic Absorption Spectrophotometric Determination of Cobalt in Foods

1985

A method is reported for determination of chromium in foodstuffs. Organic matter is digested with nitric acid, followed by oxidation to Cr(VI) and extraction with methyl isobutyl ketone (MIBK) after HCl addition. Chromium determinations are performed by flame absorption spectroscopy. Absence of interferences is verified and recovery tests are performed on food samples. Quantitation limit (3.8 ng/mL), accuracy (NBS Standard Reference Material 1,573 Tomato Leaves, 4,500 +/- 500 ng/g, found 3,860 +/- 409 ng/g), and precision (CV for vegetable matrix = 9.05%, CV for animal matrix = 14.95%) of the procedure are evaluated.

Immobilization of reagents by polymeric materials. Determination of metamizol

1992

Abstract A method for immobilization of inorganic reagents, based on the dispersion of the reagent into an unsaturated polyester solution is applied to immobilization of lead dioxide. The obtained solid is of application in a flow-injection manifold for indirect atomic absorption determination of metamizol in pharmaceutical formulations. The procedure gives a linear calibration graph up to 6 ppm of metamizol with a relative standard deviation of 1.6% (3.0 mg/l) and a sample throughput of 72 hr−1.

Continuous flow-injection-atomic absorption spectrometric method for the determination of Ondansetron

1995

Abstract A flow-injection procedure for the indirect determination of the new drug Ondansetron is proposed. The method is based on the reaction of the drug in an oxidative solid-phase reactor included in the flow assembly. The reactor was made by lead dioxide physically entrapped by polymerization; the released lead(II) was monitored by atomic absorption spectrometry at 217.0 nm. The procedure gave a linear calibration graph up to 20 μg ml−1 of Ondansetron with a sample throughput of 338 samples h−1.

Literature survey of the on-line preconcentration in flow-injection atomic spectrometric analysis

1992

The literature on the use of “on-line” preconcentration in flow injection atomic spectrometric analysis is reviewed, taking into account its application both in flame and electrothermal atomic absorption methods as well as in plasma emission spectrometry. The basis of the different preconcentration approaches, such as liquid-liquid extraction, column preconcentration and “on-line” precipitation are discussed. The literature survey reveals the analytical performance of the developed methodologies.

Speciation of tetraalkyllead compounds by flow injection — atomic absorption spectrophotometry

1990

The on-line demetallation of alkyllead compounds, with iodine, and further emulsification, provides a fast determination of total lead content in liposoluble matrices, such as gasolines. It can be carried out in a double channel manifold, using a magnetically well stirred dilution chamber for the emulsification of the samples, previous to their analysis by flame atomic absorption spectrophotometry. On the other hand, the different behaviour of tetraethyllead (TEL) and tetramethyllead (TML) can be employed for speciation of both compounds in the sample. The effect of the flow injection parameters on the sensitivity and accuracy has been studied and the figures of merit of the proposed method…

Chromium speciation in liquid matrices: a survey of the literature

2000

A thorough review of the literature published (1983 - March 1999) on chromium speciation in liquid samples is presented, and analytical techniques used in the 404 articles are summarized. The discussion focuses on atomic spectrometric techniques, which are mainly employed for chromium speciation in liquid matrices (134 articles). Details on the type of pretreatment, species, samples, techniques and analytical features of the methodologies proposed are given.

Determination of chromium in foods by flame atomic absorption and inductively coupled plasma spectrometry

1989

The use of direct determination of chromium in human urine by electrothermal atomic absorption spectrometry in diabetic patients.

1991

EDTA excess Zn(II) back-titration in the presence of 4-(2-pyridylazo)-resorcinol indicator and naphthol green beta as inert dye for determining Cr(II…

2006

The colour changes of 4-(2-pyridylazo)-resorcinol and naphthol green beta as new screening metallochromic indicator in back-titration of EDTA excess with Zn(II) to determine Cr(III)/EDTA complex was investigated with the help of tristimulus colorimetry. Specific colour discrimination (SCD) and L*, a*, b* 1976 parameters were successfully applied to evaluate the quality of colour transition at the end-point in non-alkaline media and in the presence of Zn(II) and Ca(II) which resulted in non-interfering species at 1x10(-3) M and 2x10(-3) M, respectively. The above concentrations are comparable with those used for Cr(III). Validation of the fast and accurate reported method was performed by at…