For direct simultaneous determination of Cu (II), Pb(II) and Cd(II) ions in tap water and untreated drinking water by differential pulse anodic stripping voltammetry (DPASV) with a hanging mercury drop electrode (HMDE), the effect of supporting electrolytes and deposition time on metal currents were studied. Chloride ion affects peak potentials and peak heights of Cu(II) and Pb(II). Except for potassium chloride, nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid and perchloric acid are suitable supporting electrolytes for water samples including a few colloidal particles consisting of Fe and Mn. Long deposition time is not always effective for increasing the DPASV peak currents of Cd(II) and causes the increase in blank peak currents of Pb(II). After nitric acid or hydrochloric acid was added to the 6 ml of water samples, DPASV of them with deposition time of 30 s were measured. The detection limits of Cu(II), Pb(II) and Cd(II) were 1.1, 0.8, 0.9 ng/ml, respectively. The present analysis requires only about 10 min.

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Preconcentration/AAS determination of trace Mn(II) and Pb(II) was inverstigated with xanthate immobilized silica gels (Silyl Xanthate: SX) as the chelating functional groups. Xanthate groups are chemically bonded directly to the surface-OH of four kinds of silica gels which differ in particle diameter, specific surface area, pore volume and pore diameter. Preconcentration procedure were made for small glass columns packed with 500 mg of SX. The glass columns were about 10 cm long and 0.5 cm inside diameter. The sample solutions flowed through the small columns with the aid of a peristaltic pump to maintain a constant flow rate. After washing with 20 ml of pure water, the metal ions were eluted from the SX columns with 25 ml of 0.1 M hydrochloric acid solution. The pH dependence of a preconcentration is considerably similar in the optimum pH region that is at pH 5.0 to 6.0 for Mn(II) and at pH 5.2 to 5.8 for Pb(II). At pH 5.5 of sample solutions, the maximum capacity per 1.0 g of SX is about 0.11 mmol for Mn(II) and 0.12 mmol for Pb(II). The presence of a 15-fold amount of chloride ion interferes in the preconcentration efficiency of Mn(II), and almost equal amounts of Mg(II), Ni(II), Co(II), Cu(II) and Fe(II or III) gives a poorer efficiency. This method was applied to natural waters where known amounts of Mn(II) or Pb(II) were added, and was performed to determine those metal ions in seawater and river water where very low concentrations cannot be determined directly with AAS method, except for Mn(II) in seawater.

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A simple and rapid method for the determination of virginiamycin M₁ (M₁) and S₁ (S₁) in swine, cattle and chicken muscles has been developed by means of HPLC with fluorescence detection. M₁ and S₁ were extracted from 10 g of muscle with 50 ml of acetonitrile and 5 g of Hyflo Super-Cel. The volume of filtered extract was made up to 100 ml with acetonitrile. After evaporation of 50 ml of acetonitrile solution at 40 °C, the residue was dissolved in 2 ml- and 1 ml-portions of methanol. This methanol solution, 1.5 ml of water and 3.5 ml of chloroform were placed in a low actinic test tube. M₁ and S₁ contained in methanol solution were extracted with chloroform by using a test tube mixer. After centrifugation for 5 min at 2800 rpm, the upper layer was removed and the lower layer was washed with 1.5 ml of water. After centrifugation for 5 min at 2800 rpm, the upper layer was removed and the lower layer was transferred into another low actinic test tube. The chloroform solution was dried up with nitrogen. After M₁ and S₁ were dissolved in 1 ml of HPLC mobile phase, the solution was passed through a membrane filter of 0.5 μm pore size and was centrifuged for 2 min at 2800 rpm. The upper layer was injected onto the HPLC system and peak height was measured. The condition of HPLC was as follows: Column, TSKgel ODS-120T, 5 μm, 250 × 4.6 mm i. d. (Toyo Soda); mobile phase, methanol-acetonitrile-0.015M NaH₂PO₄- tetrahydrofuran (43:22:34:1); flow rate, 0.5 ml/ min; column temp. 40°C; detection, fluorescence Ex. 311 nm, Em. 427 nm: The calibration curves were linear from 10 ng to 360 ng for M₁ and from 1 ng to 32 ng for S₁. Recoveries of M₁ added to swine, cattle and chicken muscles at the level of 0.59 μg/g were 98.9, 95.7 and 93.8%, respectively. Recoveries of S₁ added at the level of 0.17 μg/g were 99.5, 98.4 and 101%, respectively. The detection limits of M₁ and S₁ were 0.1, 0.01 μ/g, respectively.

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Double-crystal high resolution XRF was applied to the chemical state analysis of sulfur in biological samples of human hairs. Both S^2- (average value 95.4%) and S⁶⁺ (average value 4.6%) states are present in all hairs. The total sulfur and S^2- state sulfur in male hairs were higher than those of female hairs in the same country. Furthermore, the abundance of S^2- state in gray hairs was found to be less than normal, but S⁶⁺ content was slightly higher than that in normal hairs.

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ICP-AES was applied to the determination of impurities, Al, Ca, Fe, K, Mg, Na, Nb, Si and Zr, in titanium oxide samples. Titanium oxide (0.5 g) was decomposed with 2.5 ml of hydrofluoric acid and 2.5 ml of hydrochloric acid at 150 °C for 3 h in a Teflon pressure vessel. For the use of a quartz torch, the resulting solution was diluted to 100 ml with 2% w/v hydrochloric acid, after the addition of 1.6 g of boric acid for masking fluoride ion. In the case of the laboratory-manufactured alumina torch, the solution was diluted to 100 ml with 2%w/v hydrochloric acid. Because of incomplete masking of fluoride ions with boric acid, the quartz torch gave a higher background intensity at Si I 251.61 nm and a higher detection limit of Si. The alumina torch had adequate resistivity to hydrofluoric acid. For each element except Si, both torches gave the similar detection limits. The titanium matrix appreciably reduced the emission intensities of the elements of interest and increased the background level. Therefore, the standard solution for calibration required the matrix-matching with equal amount of titanium to that in the sample solutions. The analytical results by using two torches were in good agreement.

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In order to determine dissolved ozone(O₃aq) in atmospheric water droplets or ozone-treated water, an aqueous phase chemiluminescence (CL) method using Rhodamine B was studied. Standard O₃aq samples were prepared by passing air containing ozone through purified water. Equilibrium between gas and aqueous phases was attained within 30 min and it was confirmed that Henry's law held even at very low concentrations. The continuous chemiluminescent analyzer consisted of metering pumps, a glass reaction cell (0.7 ml), a photomultiplier and a photon counter. Care was taken to minimize the decomposition of O₃aq in the sampling line. The optimum reagent composition for CL intensity was determined to be 60 mg l^-1 Rhodamine B and 10mg l^-1 gallic acid. Gallic acid was added so as to obtain a faster CL response. CL intensity was proportional to the O₃aq concentration at least up to 400 ng ml^-1 and the detection limit(S/N=3) was estimated as 0.03 ng ml^-1, which was much lower than the methods currently used. The overall reproducibility including the gas-liquid partition process for samples (O₃aq: 110ng ml^-1) was ca. 9% as a relative standard deviation. Halide ions, aldehydes and hydrogen peroxide interfered with the measurement.

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The usefulness and a new concept of the cyclic FIA were demonstrated through the determination of free cyanide (CN^-) by using didodecyldimethylammonium bromide(DDAB)/uranine/sodium hydroxide chemiluminescence system. The CN^- sample dissolved in sodium hydroxide solution was injected into a circulating stream of reagent solution containing Al₂(SO₄)₃ as a neutralizer of sodium hydroxide. Under recommended conditions for cyclic FIA, i.e., 1×10^-4M uranine, 5×10^-4M DDAB and 5×10^-5 M Al₂(SO₄)₃ and 20 μl injection of CN^-sample dissolved in 5×10^-3 M sodium hydroxide, 120 samples were analyzable with a detection limit of 0.5 pg. The sample analyzing capacity of the present system was 2 times larger than that of the conventional FIA system. The strongest enhancer after CN^-, S^2- did not interfere the signal for CN^- after 120 sample injections. The present cyclic FIA system for CN^- determination could be operated for at least 30 days.

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A spectrophotometric method was developed for the determination of iodide, which is based on the precipitation of silver iodide and solvent extraction of dicyanoargentate(I) as an ion-pair with Methylene Blue. The recommended procedure is as follows. Pipette 10 ml of a sample solution containing iodide up to 12.7 μg (10^-5 M I^-) into a 50-ml separatory funnel, and add 1 ml of 4 M sulfuric acid and 1 ml of 0.7 M hydrogen peroxide. After standing for more than 5 min, add 10 ml of carbon tetrachloride and shake the funnel for 1 min to extract the iodine formed. Transfer the organic phase to another 50-ml separatory funnel and add 5 ml of 2×10^-4 M L-ascorbic acid. Shake the funnel for 1 min to back-extract the iodine in the organic phase into an aqueous phase. After discarding the organic phase, add 2 ml of 7×10^-3 M sulfuric acid, 2 ml of 2.5×10^-5 M standard silver(I) sulfate, 1 ml of 7×10^-4% himoloc solution and 2 ml of carbon tetrachloride. Shake the mixture for 2 min in order to collect the precipitate of silver iodide on the interface between the aqueous and organic phases. After removing the precipitate with carbon tetrachloride, add 1 ml of 0.7 M hydrogen peroxide, 2 ml of 8×10^-3 M sodium cyanide, 1 ml of 1×10^-3 M Methylene Blue and 10 ml of 1, 2-dichloroethane. Shake the funnel for 1 min to extract the Methylene Blue-dicyanoargentate (I) ion-pair. After standing for a given period of time, transfer the organic phase to a glass-stoppered tube and add some anhydrous sodium sulfate to remove water droplets. Shake the mixture vigorously by hand untill it becomes transparent and measure the absorbance at 657 nm against dichloroethane using 10-mm glass cells. The calibration graph shows a negative linearity up to 9×10^-6 M (1.14 ppm) iodide, and the apparent molar absorptivity for iodide at 657 nm is 1.04×10⁵ 1 mol^-1 cm^-1. The present method was successfully applied to the determination of iodide in various amounts in several natural water samples, and gave a relative standard deviation of 0.52% at 6×10^-6 M iodide level.

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GC/MS method for determination of amfenac sodium (AMF) and its metabolites (S₁, S₂ and S₃) in plasma was established. The clean-up for the determination of S₁ was efficiently attained by extraction with ethyl acetate under basic condition, and that of AMF, S₂ and S₃ was carried out under acidic condition (AMF was converted into S₁ under acidic condition). S₂ and S₃ were derivatized into the methylester and subjected to GC/MS. The detection limits of AMF and its metabolites were 5 ng/ml each in plasma. The plasma concentrations of AMF and its metabolites after oral administration of AMF capsules to human volunteers were determined by this method.

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A simple, rapid and sensitive method for the determination of V in environmental materials by polarized Zeeman AAS using pyrolytic graphite furnace was described. The sensitivity of V was increased by using an optical temperature control system in the atomizing process. When 10 mm³ of sample solution was injected into the pyrolytic graphite furnace, the optimum conditions obtained at heating stages were: drying for 90 s programmed from 100 to 160°C, charring at 400°C for 30 s, atomizing at 2850°C for 30 s and cleaning at 2950°C for 7 s. A linear calibration curve was obtained in the range of 0.253 ng of V. The detection limit was 0.06 ng and the relative standard deviation was about 2% for 0.2 ppm of V in 3% sodium carbonate solution. V concentrations in several environmental reference materials were determined as follows. The powdered sample was fused with sodium carbonate for a desired period, and V in the melt was dissolved in hot water. The solution was filtered through a glass fiber filter (Toyo GC-90), then the filtrate was made up 50 cm³ with water. The absorbance of V was measured at 318.4 nm with injection volume of 10 mm³ employing a standard addition method. The analytical results obtained by the proposed procedure were in good agreement with the certified/recommended values.

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Solvent extraction and spectrophotometric determination of an anionic surfactant, sodium laurylsulfate (SLS), in seawater was examined with Ethyl Violet (EV) as a counter ion. At pH 4.9, this surfactant reacts with EV to form an ion-associate, which can be extracted with toluene. Chloride ion also forms an ion-associate with EV and is extracted simultaneously with SLS. To eliminate the chloride interference, the organic phase was washed with dilute hydrochloric acid solution. The concentration of the surfactant can be determined by measuring the absorbance of the extract at 612 nm after back washing. Calibration cuve is linear over the range 02.0×10^-5 M (in toluene) of the surfactant and the apparent molar absorptivity is 92500 1 mol^-1 cm^-1. The recommended procedure is as follows: Take 100 ml of the sample solution containing the surfactant up to 1.0×10^-6 M in 0.5 M sodium chloride solution in a 100 ml separatory funnel. Add 5 ml of 1 M sodium sulfate, 1 ml of 0.1 M EDTA solution, 2 ml of acetate buffer solution (pH 5) and 3 ml of 8.8×10^-3 M EV solution and mix well. Shake the content with 5 ml of toluene for 35 min. After complete phase separation, the organic phase was washed with 50 ml of 0.08 M hydrochloric acid and the absorbance in toluene was measured at 612 nm against a reagent blank. Free from interferences from major constituents of seawater, this proposed method can be applied to the determination of surfactants in seawater.

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A pattern recognition method for elucidating functional groups of compounds from their IR spectra has been investigated by utilizing spectral data compiled in the Spectral Data Base System developed in our laboratory. Spectral data of about 9500 compounds were used, and error ratios in the elucidation of six functional groups (C=O, C=C, C≡N, C-O-C and NO₂ groups, and benzene ring) by using a learning machine method were evaluated. As a result, it was found that all functional groups except C=C could be elucidated with high probabilities above 85%. Thus the present method has a high performance when applied to the elucidation of functional groups from IR spectra.

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In the determination of chloride ion in colored boiler water from low-pressure boilers, the decolorization by coagulation with KAl(SO₄)₂ was a useful pretreatment in the spectrophotometric determination with Hg(SCN)₂ as a reagent. Procedure: To a stirred 50 ml sample, add 3 ml of coagulant {5 w/v% KAl(SO₄)₂· 12H₂O} to form floc. When no floc forms easily, several drops of HNO₃ (5 mol/l) should be added to the sample. Leave the sample for ca. 5 min and filter.

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High purity reagents for the pH standard solutions are needed to secure the reliability of the pH values. The reagents of potassium hydrogen phthalate, potassium dihydrogen phosphate, disodium hydrogen phosphate and sodium tetraborate were prepared by recrystallization of commercial reagents using deionized water. Impurities (Na, K, Ca, etc, ) in the reagents were compared with those in the NBS and commercial reagents. The purities of the primary reagents were higher than those of other reagents. The performance of a high sensitive pH measurement system which permits measurements at 0.0001 pH level was evaluated. The standard deviation of the pH values of the pH standard solutions prepared from the reagents was below 0.001 pH. The pH value of the pH buffer solution prepared from commercial phosphate reagents differed from those of the pH standard solutions.

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