0000000000171100
AUTHOR
José Luis Burguera
On-line microwave oven digestion flame atomic absorption analysis of solid samples
Abstract A manifold has been developed for on-line microwave oven digestion and flame atomic absorption spectrometric (FAAS) determination of metallic elements in solid samples. The use of a closed flow system permits sample treatment before analysis by FAAS, the direct injection of slurries avoids a filtration step and the interconnection of two conventional rotary injection valves allows the rapid introduction of samples and standards. The determination of lead in sewage sludge was employed as a test system for the proposed on-line sample digestion manifold. The procedure has a limit of detection of 0.2 μg Pb g−1.
Speciation of tetraalkyllead compounds by flow injection — atomic absorption spectrophotometry
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…
Comparative study of different approaches for the flow injection-fourier transform infrared determination of toluene in gasolines.
Abstract A single channel flow injection manifold has been employed to carry out the direct determination of toluene in gasolines by FT—IR without any sample pretreatment and by using different strategies. Toluene can be directly determined by measuring the absorbance at 728 cm −1 , using a base line established between 835 and 575 cm −1 ; and in this case a limit of detection of 0.01% (v/v) can be obtained with a dynamic range up to 2% (v/v). In some cases it could be convenient to determine toluene by derivative flow-injection FT—IR in order to avoid matrix interferences in the analysis of some types of gasolines. Carrying out the first order derivative FI—FT—IR measurements on the 728 cm…
Flow injection flame atomic spectrometric determination of iron, calcium, magnesium, sodium and potassium in ceramic materials by using a variable-volume injector
A series of different ceramic materials, such as porcelain, feldspar, kaolin, varnish, clay and stoneware have been analyzed. Iron, calcium and magnesium have been determined in these materials by flame atomic absorption and sodium and potassium by flame emission. The use of a variable-volume injector enables one to carry out these analyses in a flow system (after fusion of samples with lithium metaborate) and does not require different dilutions for the determination of each type of sample considered, nor the use of different flow injection manifolds. The developed procedure provides a limit of detection of 100 μg/l for Na, 70 μg/l for Ca, 50 μg/l for both Fe and K and 8 μg/l for Mg. The c…
Simple variable-volume injector for flow-injection systems
Abstract A simple and versatile variable-volume injector is described for the introduction of samples in flow-injection systems. The device delivers precisely and reproducibly (usually r.s.d.
Some observations on the sensitivity of flow-injection techniques for atomic absorption spectrophotometry
Abstract Different strategies for coupling flow-injection manifolds to atomic absorption spectrometers in order to obtain better sensitivity are compared. Using a T-connector interface, different carriers and flow compensation solvents have been assayed in an attempt to improve the sensitivity of flow-injection analysis. Manganese and copper determinations in sewage sludge have been used as a test system and the analytical parameters of both batch and flow-injection methods are compared.