Masami Suzuki

Trace analysis by flameless atomic-absorption spectrometry

The operating conditions of an atomic-absorption system based on flameless atomization have been investigated for trace analysis for Al, Cr, Cu, Fe, Mg and Mn. The sample solution on a tantalum strip was atomized by electrical heating in an inert atmosphere within an absorption chamber. This technique allows the use of small sample sizes and results in a higher sensitivity than that with the conventional flame technique. Some interference effects and applications were investigated.

Trace metal analysis of rocks by flameless atomic-absorption spectrometry with a metal micro-tube atomizer

Flameless atomic-absorption spectrometry with a metal micro-tube atomizer has been studied. The element to be determined was atomized by electrical heating of the micro-tube in an inert atmosphere within a glass chamber. A detailed study of the atomic-absorption characteristics of the micro-tube atomizer is presented. The absolute sensitivities were 2.6 x 10(-12), 2.9 x 10(-11), 2.5 x 10(-10), 1.1 x 10(-10) and 1.4 x 10(-10)g for copper, cobalt, aluminium, palladium and selenium, respectively. The interferences of cations were studied for determination of cobalt and copper. Cobalt and copper in rock samples were determined in order to evaluate the metal micro- tube atomizer.

Electrothermal atomization of calcium and strontium in a molybdenum micro-tube

The excitation and ionization of calcium and strontium in a molybdenum micro-tube atomizer and their use in atomic-absorption spectrometry are described. Increasing hydrogen flow led to complex calcium atomization profiles for absorption measurements, but decreasing hydrogen flow resulted in higher atomic emission. Ionization of calcium and its suppression by potassium were also observed. Strontium was measured effectively by atomic absorption because of the higher sensitivity. Increasing hydrogen flow resulted in a lower atomization temperature and higher absorption for strontium, while decreasing hydrogen flow resulted in higher atomic emission. No interference from 100-fold amounts of magnesium, calcium and sodium was found for atomization of strontium, but 100-fold amounts of aluminium shifted the peak temperature for strontium though with no variation of appearance temperature and peak absorption. A small shift in peak temperature was observed for strontium in the presence of 100-fold amounts of phosphate.

Atomic absorption spectrometry of tin with electro-thermal atomization in a molybdenum microtube

Abstract The atomic absorption spectrometry of tin with atomization in a molybdenum microtube is described. The addition of hydrogen to the argon purge gas improves the efficiency of atomization of tin; measurements are best done at 224.61 nm. Phosphoric acid lowers the atomization temperature of tin, and depresses the interferences from diverse elements. Tin in canned foods (fruit juices and drinks) can be determined by direct atomization after dilution with phosphoric acid. Prior extraction is necessary for analysis of geological materials.

Electrothermal atomic-absorption spectrometry of arsenic and its application to environmental samples

Electrothermal atomization of arsenic with a metal micro-tube atomizer has been studied. Thiourea and thionalide were found to give effective atomization of arsenic. A method involving extraction of the thionalide complex for determining traces of arsenic in water and soil is described.

Atomic absorption spectrometry of bismuth with electrothermal atomization from metal atomizers

Abstract Synchroscope traces of atomic .absorption signals generated during heating of bismuth salts in a metal micro-tube atomizer show features which are characteristic for bismuth when a fast-response amplifier is used. Atomization profiles of bismuth with a molybdenum micro-tube are complicated for inorganic compounds and some complexes, but addition of thiourea improves the absorption profiles and increases sensitivity. Tantalum and tungsten micro-tubes were used for comparison. The interferences of other metals on bismuth absorption and the determination of bismuth in aluminum samples are also described.

Improved sensitivity using a microcomputer for electrothermal atomic absorption spectrometry with a metal microtube

Abstract Data enhancement by signal accumulation, scale expansion after background subtraction, and smoothing with the aid of the microcomputer enables limits of detection to be improved by up to an order of magnitude. Data are reported for 15 elements.

Mechanism of interference elimination by thiourea in electrochemical atomic absorption spectrometry

Abstract The mechanism of interference elimination by thiourea in electrothermal atomization is discussed. Activation energies of atomization were measured. The experimental values for bismuth, lead, copper and cadmium were not altered in the presence of concomitants, provided that thiourea was added before atomization. These elements from complexes with thiourea which are converted to sulphides during the charring stage. Atom formation occurs from the sulphides without compound formation between analyte and concomitants.

Some observations on the interferences in flameless atomic-absorption spectrometry of magnesium

Interferences in flameless atomic-absorption spectrometry of magnesium were investigated by the use of a molybdenum micro-tube atomizer with a double indentation. Two atomization processes were compared in order to understand the interference mechanism: atomization from separate indentations, and mixture-atomization. Most elements tested gave no interference in atomization from separate indentations, whereas magnesium absorption was somewhat reduced in mixture-atomization. However, zinc and lead caused broadened absorption profiles in mixture-atomization. Chromium interfered in both atomization processes. The origin of these interferences is discussed.

Electrothermal atomic-absorption spectrometry of antimony by use of a molybdenum micro-tube atomizer.

Electrothermal atomization of antimony has been investigated to clarify the atomization characteristics and interferences from diverse elements, for accurate determination of traces of antimony. Thiourea served to lower the atomization temperature of antimony and to improve the sensitivity. Germanium and phosphoric acid were found to have a pronounced effect on atomization of antimony. The interference of various elements was suppressed in the presence of thiourea. A method involving extraction for determining antimony in metallurgical and geological samples is described.