A sample of 100 to 200mg was treated with nitric acid and hydrogen peroxide, ignited, and followed by HF-treatment to remove dissoluble and organic matters. After adding silicon internal standard, the undissolved part was collected on a membrane filter, which was subjected to X-ray diffraction analysis. Rutile or corundum of 0.1 to 1.0mg can be determined from the integral intensity ratio against silicon. Some pairs of diffraction lines suitable for determination, influences of coexisting substances, and the processes of chemical treatment are discussed. Furthermore, the present method has been applied successfully to several atmospheric dust samples collected in urban, industrial, and farming areas. Rutile and corundum in the samples were concentrated more than 10 times. The detection limits of rutile and corundum were 0.04% and 0.02%, respectively.

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Direct current (DC) and differential pulse (DP) stripping voltammograms of sulfide at the low ng ml^-1 level in 0.2M sodium hydroxide solutions with a silver electrode have several peaks, all of which should be considered for quantification. The sum of the heights of all the stripping peaks is proportional to the sulfide concentration in the DP mode, but is not so in the DC mode. When the peak-area sum is used instead of the peak-height sum, a proportional relationship exists in both modes. To obtain reproducible voltammograms, the silver electrode is electrochemically treated before the electrodeposition of sulfide to remove the oxide film on it.

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The conditions under which each species of thiosulfate, sulfite and sulfide can be selectively separated from their mixtures have been established. The proposed method comprises three procedures: excess iodine for its reaction with the thiosulfate separated in Procedure I and the thiosulfate formed from sulfur dioxide in Procedure II; the thiocyanate formed from hydrogen sulfide in Procedure III is spectrophotometrically measured. The sulfur dioxide separated from a mixture of thiosulfate and sulfide was introduced into a solution containing a buffer and sulfur; the sulfur dioxide was completely converted into thiosulfate. Procedure I can be applied to the determination of up to 4.8×10^-4M thiosulfate in the presence of sulfite and sulfide, Procedure II up to 4.8×10^-4M sulfite in the presence of thiosulfate and sulfide, and Procedure III up to 6×10^-4M sulfide in the presence of thiosulfate and sulfite. Good recoveries of thiosulfate, sulfite and sulfide from hot-spring and lake-water samples were achieved using the proposed method.

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A catalytic photometric method for the determination of trace amounts of iodide is proposed. In the presence of iodide, chlorpromazine is oxidized by hydrogen peroxide in a sulfuric acid solution to form a red intermediate, which is further oxidized to a colorless compound. The reaction is followed by measuring the increase in the absorbance at 525nm; the maximum absorbance is obtained on an absorbance-time curve at a given reaction time. Since the maximum value increases with an increase in the iodide concentration, this value is used as a parameter for the iodide determination. Under the optimum experimental conditions (1.0×10^-3M chlorpromazine, 1.5M sulfuric acid, 2.0M hydrogen peroxide, 30°C), iodide in the range 0.2-10μg l^-1 can be determined. The relative standard deviations are 0.8, 2.6 and 4.2% for 6.0, 2.0 and 0.6μg l^-1 iodide, respectively. Although iodate shows the same catalytic effect as iodide at the same concentration as iodine, free iodine shows a somewhat lower catalytic effect. The procedure has been applied to the determination of iodide in natural water samples.

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The effect of cationic surfactants at concentrations below their critical micelle concentrations on the absorption spectra of the sulphonephthalein dyes was studied. The addition of a cationic surfactant to a Bromocresol Purple (BCP) solution buffered at about pH 8 resulted in a large spectral change: the color changed from blue to light-yellow. The mechanism of this color-change reaction is based on ion association of the quaternary ammonium cation with the monovalent dye anion(HBCP^-) produced by the addition of a proton to BCP^2- and the formation of a precipitate accompanied by ion association.

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The formation rate of Ni(II) and Co(II) complexes with 5-octyloxymethyl-8-quinolinol was investigated in nonionic surfactant systems. The distribution of metal ions and of ligands between the aqueous and micellar phases affected the reaction rate. The slowest reaction was obtained for Triton X-100 and the reaction rate in the micellar phase was thirty times slower than the rate in the aqueous phase. The slow reaction in the micelle was applied to the determination of Ni(II) and Co(II). The formation of the Co(II) complex was forty-four times faster than Ni(II) at pH 7.0. The working curve for each metal was linear in the concentration range between (0.2-5.0)×10^-5mol dm^-3.

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A spectrophotometric study of protein/Chromazurol B/beryllium(II) system is reported. In the manual spectrophotometric method, Beer′s law is obeyed for protein (as human serum albumin, HSA) concentrations up to 150μg/ 10ml. This procedure is about 3 times more sensitive than the Pyrogallol Red-molybdenum(VI) method. In the flow- injection method which employs a single-channel flow manifold system, the calibration graph is linear for the HSA range from 0.1 to 1μg/10μl by direct injection. Results obtained by the present manual method and the Pyrogallol Redmolybdenum(VI) method agree with each other in the determination of urinary proteins. No significant difference in results was observed between the manual and flow-injection methods.

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Studies on the liquid-liquid extraction(LLX) behavior of trace level niobium and tantalum, ⁹⁵Nb and¹⁸²Ta, in HF, HCl, HNO₃ and H₂SO₄ acid media with high molecular weight amine, trioctylamine, under different experimental conditions revealed that the extraction of tantalum is always higher than that of niobium, whatever be the acid or acidity in the aqueous phase. At optimal conditions, quantitative extraction of tantalum and its complete decontamination from niobium has been achieved in HCl and HNO₃ media. In HF and H₂SO₄ media, the coextraction of niobium with tantalum can not, however, be avoided completely, because it has comparatively more affinities for fluoro- or sulfato- complex formation in the respective acid media. The purity and the extents of separation of the tracers by the liquid anion exchanger at different stages have been verified by means of Y-ray spectroscopy.

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In an alkaline solution, aliphatic primary amines react with salicylaldehyde and beryllium(II) to form fluorescent Schiff base complexes. A flow injection fluorometry for the determination of aliphatic primary amines based on this reaction has been investigated. By using the established method, methylamine could be determined in the range of (6×10^-6-6×10^-3)mol dm^-3within a relative standard deviation of 3%. Ethylamine, 1-propylamine and 1-butylamine were determinable in the range of (3×10^-5-8×10^-3)mol dm^-3. With a flow rate of 0.4cm³ min^-1, 30 samples could be analyzed per hour. The proposed method was substantially inactive for secondary and tertiary amines, and was successfully applied to the determination of methylamine (0.007-0.008%) contained in commercial dimethylamine reagents.

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As crystal-coating materials used for ammonia sensors, hydrochlorides of pyridoxine, glutamic acid, histidine, methionine, alanine and cysteine were examined. By using the first three of them a satisfactory detection of ammonia in the wide range from 1ppb to 10³ppm could be obtained. Under optimized conditions the lifetime of a histidine hydrochloride-based sensor can be extended to 1 month, whereas for a pyridoxine hydrochloride-based detector, due to the possibility of regeneration, even up to 4 months is possible. Among several compounds examined as coating substances for sulfur dioxide detection, tripropylamine and tridodecylamine can be utilized only for the determination of a large concentration of SO₂, above 0.1% v/v. N, N, N′, N′-tetrakis(2-hydroxyethyl)ethylenediamine (EDTE) and N, N, N′, N′-tetrakis(2-hydroxypropyl)ethylenediamine (EDTP) can be employed for a much lower range of SO₂ concentrations, namely 1 to 1000 and 0.01 to 1000ppm for EDTE and EDTP, respectively. A lifetime study of SO₂ detectors has shown that although an EDTP-based SO₂ sensor can be used for 2 months, its detectability gradually deteriorates. Upon using an EDTP-based sensor some disadvantages of serial syringe dilution for the preparation of gas standard mixtures were noted. For a comparison, an alternative procedure employing gas-permeable tubing was proposed.

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In this paper, a new sensitive and selective differential pulse voltammetric method for the preconcentration and determination of copper(I) in an aqueous medium is proposed. A carbon paste electrode modified with Nafion and 2, 2′- biquinoline is used for the accumulation of copper(I) from a dilute solution, followed by voltammetric quantification of the accumulated analyte. The electrochemical behavior of the accumulated analyte is characterized by cyclic voltammetry and differential pulse voltammetry. The surface of the modified electrode is renewed by holding the electrode at a positive potential (0.8V (vs. SCE)) for a certain period of time. The factors, which influence the accumulation and electrochemical response, have been investigated. A detection limit of 1nM was obtained following 2min of accumulation time. For 10 accumulation/determination/renewal cycles with 50nM Cu(I), the response could be reproduced with a 4.4% relative standard deviation. Satisfactory results were obtained for the determination of copper in a variety of biological samples.

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A sensitive and selective method for the simultaneous determination of ribonucleosides (adenosine, cytidine, guanosine, inosine, uridine and xanthosine) and 2′-deoxyribonucleosides (2′-deoxyadenosine, 2′-deoxycytidine, 2′-deoxyguanosine and thymidine) of biological importance (ten species in all) is described. High-performance liquid chromatography with precolumn fluorescence derivatization using 2-(5-chlorocarbonyl-2-oxazolyl)-5, 6-methylenedioxybenzofuran is employed. The reagent reacts selectively with 5′-hydroxyl group of the sugar moieties in the nucleosides to produce the corresponding fluorescent ester derivatives. The resulting ten esters are separated isocratically by chromatography on a reversed phase column, TSKgel ODS-80T_M, and detected fluorometrically. The detection limits (signal-to-noise ratio=3) for the nucleosides are 2-12pmol on column.

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Counter alternative current chromatography was applied to the purification of food mono-azo dyes. Commercially available reagent-grade Food Red No. 2, Red No. 102 and Yellow No. 5 allowed the presence of ca. 99.0, 98.7 and 96.1% of the main dye, respectively, according to high performance liquid chromatography. The phase system used for purification comprised 2-butanol : water (1:1 by volume). Purified Red No. 2, Red No. 102 and Yellow No. 5 were obtained in proportions of 99.7 (ca. 110mg), 99.5 (ca. 280mg) and 99.3% (ca. 290mg) from 1g (Red No. 2, Red No. 102) and 2.5g (Yellow No. 5) of the commercial dyes.

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6-Methoxy-2-methylsulfonylquinoline-4-carbonyl chloride was found to be a highly sensitive fluorescence derivatization reagent for both primary and secondary alcohols in high-performance liquid chromatography. Its reactivity was investigated for 1-propanol, benzyl alcohol, cyclohexanol, and 1-hexanol. The reagent reacted with the alcohols or phenol in benzene in the presence of pyridine to produce the corresponding fluorescent esters, which could be separated on a reversed-phase column, Cosmosil 5C₁₈-AR, with aqueous 70% (v/v) acetonitrile. The detection limits (S/N=3)were 0.07pmol for 1-propanol, 0.1pmol for 1-hexanol and for benzyl alcohol, and 0.7pmol for cyclohexanol for an injection volume of 10μl.

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The influence of chromatographic conditions on the binding capacities (W_capa) of hydroxyapatite (HAP) for globular proteins was studied. The amount of proteins adsorbed on HAP depended on the loading method. The W_capa values were affected by the concentration of sodium phosphate buffer, which was interpreted on the basis of a change in the area of the adsorbing surface of the HAP crystal. The W_capa values were also affected by pH of the buffer, which would be related to both size and charge effects of a protein molecule. The adsorption behavior in the presence of two kinds of proteins was affected by the combination, loading procedure and load ratio of the two tested proteins.

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An optimization method for the dual-flow countercurrent extraction of a mixture, the components of which show a concentration dependency in its distribution ratio, has been developed. As an experimental demonstration, commercial glycyrrhizin (about 90% purity) was purified to 99.8% with high recovery using a two-phase system (1-butanol and 0.1M NaCl) in the presence of 0.02M tetrabutylammonium hydroxide, and under the optimum conditions of the present method. To acquire 90.0% recovery of glycyrrhizin in an organic extract, the flow rate of the organic solvent was calculated to be 0.943ml/min (aqueous solvent, 1.06ml/min). Extraction performed at the derived flow rates obtained 87.2% recovery of glycyrrhizin in the organic extract, showing the propriety of the optimization method.

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The emerging discipline of Biological Trace Element Research (BTER) demands that adequate considerations be given to both biological and analytical standardization while planning an investigation. Unfortunately, the "bio" dimension of the analytical problem in the BTER area, has been rather slow in unfolding. This lack of appreciation has been a major setback since the early days of BTER, delaying the onset of multidisciplinary approaches that are vital for conceiving meaningful investigations. The presampling factors e.g., biological variations, environmental influences, post-mortem changes and intrinsic (e.g. differences in residence times of various elements in the blood stream) and inadvertent situations (e.g. medico-legal restrictions), are potential sources of serious errors, and require careful evaluation and data interpretation. Yet, these are poorly identified and currently, very little effort is expended to evaluate them. Concerning analytical standardization, progress in technical aspects of sampling are preparation, instrumentation, calibration procedures, increased awareness of matrix interferences and preparation of primary standards have collectively contributed to several improvements. However, information on long-term storage (several years) and its impact on the validity of the stored biomaterial, and experimental findings on the quantitative recovery of biominerals during acid decomposition of different types of sample matrices are still scarce.

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Determination of trace metals in blood, serum and plasma presents an important problem of increasing importance from both medical and environmental points of view. For many metals, atomic absorption spectrometry is a method of choice. Nevertheless, a significant obstacle arises because of the lack of availability of proper reference materials, especially ones having the metal content of the order of a few nanograms per milliliter. In our studies dealing with determination of lead, cadmium, cobalt, manganese, aluminium and chromium, calibration with model aqueous solutions and with serum simulating albumin solution was used and the effects of matrix materials were noted. Some improvement may be achieved when matrix modifiers-stabilizers have been used. The often used quantification procedure based on standard addition may also lead to erroneous results because the form in which the analyte is added to the sample does not reflect the speciation in the real samples. This indicates that the problems cannot be considered as completely solved and further studies are indispensable.

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The reading of phase diagrams is effective when considering high-temperature reactions during asking and the beginning of atomization in graphite furnace atomic absorption spectrometry. The origin of double-peak signals in the direct atomization of metal samples could be explained; the calibration curve for Pb in Fe could be utilized for Pb in Cu because of their similar phase diagrams. The role of a metal matrix modifier could be considered using phase diagrams between the matrix modifiers and analyte elements. The combinations of the modifier metals and analyte elements have been classified in three cases: effective, moderately effective and ineffective.

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Digestion (ashing) methods for atomic absorption spectrometric determination of metallic components in foods were investigated. Four ashing methods were employed: the dry asking using a crucible and a gas burner, the wet ashing in beaker heated on a hot plate, the wet ashing heated in commercial microwave ovens and the wet ashing heated by the irradiation with extreme infrared (IR) light. The best ashing method was the IR method.

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A method is described for the direct determination of manganese in biological samples utilizing electrothermal atomization atomic absorption spectrometry with a molybdenum tube atomizer and a matrix modifier. The atomization characteristics of manganese were evaluated in a mixture purge gas of argon and hydrogen. A direct calibration method with manganese standard solutions and an ultrasonic agitation method of a solution containing sample powder were used. The interference caused by large amounts of interferents was investigated, and eliminated by the addition of thiourea. Biological samples were directly analyzed with satisfactory results.

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The effective temperature of atomic vapor in a graphite furnace was studied in order to minimize chemical interference during the determination of trace elements in whole blood. The effective temperature of atomic vapor, which corresponds to the sample temperature, was raised to about 500°C by using a rapid heating method combined with platform techniques and a Pd matrix modifier. As a result, this technique has been found to be effective in minimizing interference in whole blood analysis without any sample pretreatment. On the other hand, the residue of a whole blood sample and the Pd modifier remaining after asking was something like porous carbon or sintered metal. This finding strongly supports the superiority of the peak-area method over others used in this assay format. Simultaneous direct determinations of Cr, Ni, Mn, and Pb in whole blood can be carried out by applying a combination of rapid heating, platform and Pd matrix modifier techniques.

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A concentration procedure was developed for the direct determination of cobalt and nickel at sub-ppm levels in biological samples by Zeeman atomic absorption spectrometry (Z-AAS), because the sensitivity of Z-AAS is at μg/g level for these elements even if the solid sampling technique is applied. For this purpose, biological samples were ashed by a muffle electrothermal furnace before the atomic absorption measurement, because the masses of biological samples are at least reduced to less than one fifth when they are ashed in the electrothermal furnace. The concentration factors of 5-50 were obtained for the biological samples. The concentration factors depend on the total amounts of Na, K, Mg and Ca.

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Concentrations of trace elements in environmental reference materials prepared by the National Institute for Environmental Studies, Japan (NIES) and by the National Institute of Standards and Technology, USA (NIST) were determined by instrumental neutron activation analysis (INAA). NIES CRM No. 5 Human Hair, No. 6 Mussel, No. 7 Tea Leaves, No. 8 Vehicle Exhaust Particulates, No. 9 Sargasso and No. 10 Rice Flour-unpolished samples (ca. 150-1200mg) and NIST SRM 1632a Bituminous Coal, SRM 1635 Sub-bituminous Coal and SRM 1633a Coal Fly Ash samples (ca. 10-150mg) were irradiated at the Musashi Institute of Technology Research Reactor (MITRR). Concentrations of 28-52 elements in these NIES and NIST environmental reference materials were determined by two irradiation methods and four Y-ray counting methods. The determined values were in good agreement with the NIES and NIST certified values.

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A helium microwave-induced plasma (MIP) at atmospheric pressure has been generated in a modified TM₀₁₀ Beenakker cavity. The MIP was coupled with a laboratory-built mass spectrometer used to measure the isotope ratios of Fe, Br and Se, which are not easily measured by an Argon inductively coupled plasma (ICP) source, due to spectral interference. In helium MIP, the analyte signal intensities are maximum when a torch edge is sampled; unidentified molecular ions appear across the entire mass range when the torch center is sampled. The measured isotope ratios agree quite well with the accepted values, and the detection limits are in the low-ppb range.

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