Reagents having a high redox power (cobalt(III) and chromium(II) ions) were applied to on-line pretreatments in flow analyses. A flow-through electrolysis cell for continuous reagent generation was assembled and put in a system of FIA or HPLC. The cobalt (III) ion was strong enough to oxidatively decompose diverse organic compounds within a short time ( < ca. 10 min, depending on the chemical structure of the compounds), even at ordinary temperature. Thus, the cobalt(III) pretreatment was successfully applied to the FIA determination of total mercury and organic phosphorus; organomercury and organic phosphorus compounds were digested to mercury(II) and phosphate ions, respectively, which are detectable species by subsequent cold-vapor (CV) - atomic fluorescence (AF) and Molybdenum Blue spectrophotometric detections. Further, the author has proposed a novel method for a chemical oxygen-demand determination based on cobalt (III) oxidation, because it can be done rapidly using a simple FIA manifold with no requirement for a heating process. Chromium(II) ion, on the other hand, has a very strong reducing power. This ion can completely reduce the stable mercury-iodide complex, HgI₄^2-, to elemental mercury, thus enabling AF detection. In the present method, the addition of iodide ion ( >10 mg dm^-3) to a sample solution gave good results with respect to the accuracy and precision, because iodide ions act as a stabilizer against the coexisting interfering substances and/or mercury deposition at the inner wall of the manifolds. A reversed-phase HPLC system coupled with CV generation based on chromium(II) reduction and AF detection was developed for organomercury speciation. An on-line reagent-generation method was concluded to afford great advantages to flow analyses. It enables the application of highly reactive (thus unstable) or poisonous reagents, which are impracticable under normal analytical condition, because the process from reagent generation to its use can be done within a short time in semi-closed flow system isolated from the atmosphere.

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Ukiyo-e, traditional Japanese woodblock prints, are the most prevalent pictorial art form in the world. Their artistic impact on western impressionist artists is well known as the cultural phenomenon "Japonisme". A non-destructive determination of the red (R1R3) and yellow colorants (Y1Y3) in the original ukiyo-e prints "Yokkaichi" by Katushika Hokusai, printed in ca. 1823, and blue colorants (B1B3) in the original ukiyo-e prints "Evening Snow at Mokuboji (Mokuboji Bosetsu)" by Gototei Kunisada, printed in ca. 1821, was performed by a 3-D fluorescence method using a quartz fiber optic apparatus. Comparison of the contour plot diagram of the 3-D fluorescence spectra of the above samples with those of control samples proved that the red colorants (R1R3) were printed with a dyestuff obtained from the plant Carthamus tinctorius L.. petal, "Safflower", the yellow colorants (Y1Y3) with a dyestuff obtained from the plant Curcuma longa L.. root, "Turmeric", and the blue colorants (B1B3) with a dyestuff obtained from the plant Polygonum tinctorium Lour. leaf, "Indigotin", respectively.

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The extraction of zinc(II) with 5-(4-nitrophenylazo)-7-(4-ethyl-l-methyloctyl)-8-quinolinol(HNEQ) was investigated using chloroform, 1, 2-dichloroethane, isobutylmethyl ketone (MIBK), and 1-octanol as diluents. HNEQ exhibited a higher extractability toward zinc(II) than did 8-quinolinol and Kelex 100. The extractability of zinc(II) with HNEQ increased in the following order of chloroform < 1, 2-dichloroethane < MIBK < 1-octanol. The extraction constants K_{ex, n} = [Zn(NEQ)₂(HNEQ)_n]_org[H⁺]²/[Zn²⁺][HNEQ]⁽²⁺ⁿ⁾_org and the formation constants (β_{s, n}= [Zn(NEQ)₂(HNEQ)_n]_org/[Zn(NEQ)₂]_org [HNEQ]ⁿ_org) of the self-adduct complexes [Zn(NEQ)₂(HNEQ)_n] in the organic solvents were dependent on the characteristics of the organic solvents. MIBK and 1-octanol provided larger formation constant of the self-adduct complex than did chloroform and 1, 2-dichloroethane. This may be ascribed to the coordination of MIBK or 1-octanol to the Zn(II)HNEQ complex and/or to the hydration of Zn(II)-HNEQ complex with MIBK or 1-octanol. It was also found that Zn(II)-HNEQ strongly absorbs at 522 nm (λ_max=8.40 × 10⁴ cm^-1mol^-11, chloroform) and 543 nm (λ_max=8.40 × 10⁴ cm^-1 mol^-11, 1-octanol).

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The multielement determination of trace elements in river water certified reference materials ( JAC 0031 and JAC 0032), issued from the Japan Society for Analytical Chemistry, has been carried out by ICP-MS and ICP-AES. The chelating resin preconcentration method, using Chelex® 100, was employed for the enrichment of most trace elements, including rare-earth elements, while some of the elements were determined by direct sample introduction without any pretreatment. As a result, the concentrations of 37 elements in river-water certified reference materials were obtained in the present experiments. Their concentrations ranged from 1.23 × 10^-3gl^-1 for Ca to 1.2 × 10^-12 g l^-1 for Tm. The analytical values for Ca, Na, Mg, K, Al, B, Fe, Cu, Zn, and Mn werealmost in good agreement with the certified values, while that for Cr was not because of poor recovery in preconcentration. In addition, the REE (rare earth elements) distribution pattern of JAC 0031, normalized by the REE concentrations of continental shale, was compared with those of the Lake Biwa surface water and samples from 24 rivers in Japan.

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An analytical method for the determination of glucuronic acid in human serum was developed by high-performance liquid chromatography (HPLC) using an ion-pair method, and the optimum analytical conditions were investigated. This method involves the acidic degradation of 200 μl of human serum with 4 M sulfuric acid, neutralization with sodium hydroxide, a reaction with 0.5 M 3-metyl-1-phenyl-5-pyrazolone (PMP) methanol, and neutralization with 0.4 M sulfuric acid. Excess reaction regent was extracted with chloroform, and an aliquot of the aqueous solution was injected to the HPLC. By using an ion-pair reagent, glucuronic acid and glucose in human serum could be separated. Under the optimized analytical conditions, the calibration curve was linear over the range 550 mg/l. The recoveries of glucuronic acid from human serum samples at a level of 550 mg/l were 8294%. The intra-day and inter-day precision of the method were 0.64.3% (n = 5) and 4.36.9% (n = 5), respectively. The concentration of glucuronic acid in human serum was constant for 30 days at -20°C. This method was applied to the determination of glucuronic acid in human serum after single oral administration of glucuronolactone to volunteers.

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A simple method has been investigated for the direct determination of trace silver by graphite-furnace AAS with a punching technique after collecting the N, N-diethyldithiocarbamate (DDTC) complex on a membrane filter. The analytical procedure is as follows : 5 ml of 2% diammonium hydrogen citrate, 2 ml of 0.5% DDTC and 5 ml of 0.3% tetradecyldimethylbenzylammonium chloride (Zeph) are added into a 250 ml sample solution (pH 9) containing less than 0.24 ng/ml of silver(I). After standing for about 30 min at 60°C, Silver(I) is quantitatively collected on a cellulose-nitrate membrane filter (diam., 17.2 mm; pore size, 0.10 μm) by suction filtration. For a direct AAS determination, a small disc (diam., 2.0 mm) is taken from the membrane filter with a paper punch and introduced into a graphite furnace. The optimal thermal programs are as follows: drying at 160°C for 60 s, ashing at 600°C for 40s, atomization at 2400°C for 5 s in an argon gas atmosphere (flow rate, 3.0 1/min). The 328.1 nm line was used to quantify silver by the peak-area method with a deuterium lamp-background correction. The limit of detection (LOD) from a 250ml sample solution is 12 pg/ml. Furthermore, silver(I)-DDTC complexes collected on a membrane filter were observed by scanning-electron microscopy.

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The determination of the total tin inbiological materials was studied using a calibration method involving ICP-MS. Prior to an ICP-MS determination, samples were subjected to microwave-digestion with HNO₃. The detected intensities for all tin isotopes increased along with an increase in the HCl concentration, while the intensities did not vary with the HNO₃ concentration. The addition of HNO₃ acted to control the interference by 0.02 M of HCl. The total tin concentrations in biological reference materials (NIES No.11, No.6, and No. 5) were examined by the present method, and agreed well with the reported reference values. In the case of preparing 100 mg of dry samples, and obtaining a final extract volume of 10 ml, the detection limit was 10 ng Sn/g-d.w. in the present study. Considering all of these results, it can be concluded that the present method is applicable with high accuracy and sensitivity for determining the total tin in biological samples.

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Concerning the spectrophotometric determination of cationic surfactants (CS) with anionic dyes, when a large amount of anionic surfactants (AS) is contained in a water sample, CS can not be determined, because it reacts with AS to form a CS-AS ion associate and doesn't react with anionic dyes. A method is proposed to avoid interference from AS based on the extraction of the CS-AS ion associate formed into an organic solvent from water samples to separate it from any excess of AS and color development by replacing AS in the CS-AS ion associate extracted with anionic dyes. In the presence of dodecylsulfate (LAS) as AS and sodium chloride, CS, such as alkyl trimethyl ammonium salts, tetraalkyl ammonium salts, alkyl dimethyl benzyl ammonium salts and alkyl pyridinium salts, was extracted as the CS-AS ion associate into 1, 2-dichloroethane. When a tetrabromophenolphtalein ethylester dye anion (TBPE) was used at pH8.510 as anoinic dyes, a CS-TBPE ion associate was formed in 1, 2-dichloroethane and was measured spectrophotometrically at 610 nm. The absorbance was propotional to the concentration of CS. Good results were obtained on recovery tests using river and sea water samples containing AS in the range of 0.120.16 mg as LAS/1.

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