0000000000171101
AUTHOR
V. Carbonell
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.
Slurries Introduction in Flow Injection Atomic Absorption Spectroscopic Analysis of Sewage Sludges
Abstract The direct introduction of slurries in flow Injection-flame atomic absorption spectroscopy has been studied using a single-channel manifold. The influence of flow Injection parameters on the sensitivity and accuracy of this procedure has been established. A method has been developed for the determination of copper, manganese, and lead In sewage sludge where batch digestion of the samples In a microwave oven is carried out before dilution. Both sensitivity and limit of detection of the flow Injection analysis procedure are adequate for the analysis of actual samples (the limit of detection was 0.06, 0.05, and 0.3 ppm for copper, manganese, and lead, respectively). The accuracy of th…
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…
Direct FIA—AS determination of potassium and magnesium in cement samples by use of the slurries approach
A direct procedure has been developed for the flame atomic determination of potassium and magnesium in cement samples. A 50-mg sample is dispersed in 25 ml of 0.13M nitric acid; 100 mul of this slurry is injected in a double channel FIA manifold simultaneously with 100 mul of a 10% (w/v) lanthanum solution. This procedure allows the rapid extraction of potassium and magnesium by leaching of the sample; nitric acid is not necessary if only potassium must be determined and the sample can be diluted with only distilled water. Aqueous standards are used. The manifold employed includes a well-stirred mixing chamber, which provides an adequate on-line dilution of the sample, in order to obtain em…
Direct determination of calcium, magnesium, sodium and potassium in water by flow injection flame atomic spectroscopy, using a dilution chamber
A simple procedure to carry out the direct analysis of calcium, magnesium, sodium and potassium in water by flow injection analysis (FIA) using flame atomic absorption spectroscopy (AAS) or flame photometry (FP) has been developed, using a well stirred dilution chamber to extend the calibration range, and both a double injector and the merging zone technique to add a lanthanum solution to samples and standards. The results obtained in the analysis of real samples agree with those found by a batch flame atomic procedure. The use of the dilution chamber makes it possible to carry out the calibration using the dilution profile of a single concentrate standard for each element, and an empirical…
Flow injection flame atomic absorption analysis of Fe and Mn in cement samples
A new procedure has been developed for the determination of Fe and Mn in cements. It consists in dispersing 50 mg of the solid sample in 25 ml of 0.15 mol/l HNO3 and 0.12 mol/l HCl solution. Acid slurries are heated at 50°C for 10 min and then different volumes of the slurry are injected into a water carrier stream. This previous acid treatment leaches the elements to be determined and permits the use of acid solutions as standards. For the Mn determination, the use of a single line flow injection manifold provides a limit of detection of 0.03 mgl−1 and a dynamic range up to 6 mgl−1. For the determination of Fe, the on-line dispersion of samples, using a well stirred mixing chamber, increas…
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.
Literature survey of the on-line preconcentration in flow-injection atomic spectrometric analysis
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.