Correlation photoacoustic technique has been applied to the study of energy transfer of an organic gas, biacetyl, in comparison with the results obtained by the ordinary phase technique. The correlation photoacoustic spectra of the first and the second kind were measured at room temperature, 30Torr, where the spectra of the second kind were measured at the delay times between 0.06 and 3.30ms. This can be regarded as the measurement of time resolved photoacoustic spectra, a new application of correlation photoacoustics. In the time resolved spectra the intensity of the absorption band at 285nm growed faster than that at 455nm. This is consistent with the results reported in terms of the phase lag between the fast and the slow heat. When the oxygen gas was added (10Torr), each spectrum showed quite a similar pattern, showing the quenching effect of the gas added.

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A fiber-optic pH sensor has been constructed by immobilizing fluorescein isothiocyanate (FITC) on the end surface of the optical fiber. The pH response is reversible in the range 4.0-6.9, precision being±0.1. Due to implantation of FITC as a monolayer, the intrinsic response time is less than 10ms.

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A photoacoustic densitometry technique by laser beam scanning is described. The laser beam was scanned on the photoacoustic cell without chopping or modulation. The photoacoustic signals generated by fast laser beam scanning were converted from analogue to digital data and then processed by a microcomputer. The signal intensity from the sample increased concomitantly with decrease in the scanning speed. The chromatogram obtained by this method, i.e. the waveform of the signal, was different in shape from that of the conventional photoacoustic densitometer. The reproducibility of measurement for 0.03 to 0.25μg Malachite Green was 1.7-4.5% (RSD).

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An algorithm and a computer program applicable to automatic qualitative analysis were developed of the carbon-13 NMR spectral data base. This algorithm was based upon a kind of pattern recognition method, where the assembly of the chemical shifts was patterned by the number of peaks around each peak. The similarity between the unknown and the reference compounds in the data base was evaluated by the similarity of their patterns, by the average difference of the chemical shifts which have the same pattern, and by the ratio of the number of peaks of the unknown and the reference compounds. The method was applied to the identification of some unknown compounds and compared with the results certified by the gate decoupled analysis of the carbon-13 NMR spectra. The results were shown to be quite successful.

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A computer program, called MAXFIT, has been developed for the automated recognition of the largest common substructure among a diverse set of chemical structures. This approach is based on a substructure search technique. Five different search levels which were defined with weighted graph representation of the chemical structures are available in the search. The search level can be specified interactively. Applications to structure-activity problems, including sweetners and opiates are presented to illustrate the abilities of the program.

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In order to clarify the reason why the normal 1:2 complex and/or its self-adducts are not extracted, but the ion-pair of the dimer complex is, when a weakly acidic nickel(II) solution containing an anion X^- such as perchlorate is shaken with an 8-quinolinol (Hql) solution of organic solvents, Ni-Hql-X (X: ClO₄, I and SCN) complexes were formed in ethanol solutions. Their composition, thermal analyses and IR spectra are discussed in connection with their molecular structures. Each Ni-Hql-X complex consists of a binuclear complex cation, [ H₃(Niql₃)₂]⁺ and X^-. The binuclear cationic complex, [H₃(Niql₃)₂]⁺, in which two Niql₃^- are joined by three very strong hydrogen bonds, is so stable in solution and solid state that its ion-pair complex, [H₃(Niql₃)₂]⁺X^-, can be extracted into organic solvents and precipitated in aqueous solutions.

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Sodium ion exchange behavior was investigated in forward and backward directions on α-hafnium phosphate which had been prepared by the direct precipitation method. pH-Titration curves and X-ray powder diffraction patterns for the exchanged solid indicate that the ion exchange proceeds in two steps, involving formation of an intermediate monosodium salt with large interlayer distance of 11.9Å. α-hafnium phosphate was reproduced toward
the end of the backward exchange, in contrast to the case of α-zirconium phosphate, where much more hydrated θ-zirconium phosphate formed. Preliminary experiments of ternary H⁺-Na⁺-Cs⁺ ion exchange system were also attempted, as well as caesium ion exchange on monosodium form of α-hafnium phosphate.

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A new technique is presented for the determination of iodide and sulfide concentrations in aqueous solutions. The method is based on the ease with which the inorganic anions can be converted into their p-nitrobenzyl derivatives with p-nitrobenzyl bromide. The resulting derivatives are subsequently determined by high performance liquid chromatography with a 5-μm ODS separation column and ultraviolet (254nm) absorption detection. By this method, iodide and sulfide could be determined in the concentration ranges of 0.2-2.0mM and 60-600μM, respectively. Also discussed are the effects of added acid or base, reaction temperature, concentration of p-nitro-benzyl bromide used as the derivatizing reagent and reaction time.

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A complexing material, 2-mercaptobenzothiazole loaded silica gel (MBT/SG), was prepared for rapid preconcentration of trace amounts of silver(I) from water samples. Silver(I) was quantitatively retained on the MBT/SG from solution of pH 0-6.3 in batch experiments, while the untreated silica gel captured only 5% of the element in the solution. The retention capacity of the loaded gel was about 8.8mg Ag g^-1 (81.5μmol g^-1) at pH 4.0. The mole ratio of MBT to silver was about 8.3. Silver was quantitatively retained on the MBT/SG column at a high flow velocity (18.8cm min^-1). The silver retained on the column was completely eluted with 10-15cm³ of 0.1mol dm^-3 nitric acid containing 2% thiourea, and directly determined by one-drop atomic absorption spectrometry. Silver contents of near-shore seawater were determined by the present method.

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A method was developed for the determination of Se and Te in coal and coal ash with graphite furnace atomic absorption spectrometry(AAS). Se and Te were separated from sample solutions by coprecipitation with As(III) carrier. Since absorbances of Se and Te in AAS measurements were affected by As concentration, it was kept constant in the final sample solution. Results of Se in the reference materials, NBS SRM 1632a and NBS SRM 1633a, agreed with their certified values. Coefficients of variation for NBS SRM 1632a were 12% for Se and 24% for Te. The concentrations of Se in 6 sorts of coal, obtained by the newly developed method, ranged from 0.20 to 1.38ppm, with an average of 0.51ppm, and those of Te ranged from 0.037 to 0.075ppm, with an average of
0.058ppm.

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A new method is proposed for the determination of Cl^- in water. An excess amount of Hg²⁺ is added to the solution containing Cl^- to form stable mercuric chloride complexes. Addition of a chloroform solution of ⁶⁰Co(PDC)₃ follows. The free Hg²⁺ that escapes from the complex formation can substitute for ⁶⁰Co in ⁶⁰Co(PDC)₃ after shaking, so an equivalent amount of ⁶⁰Co is released in its ionic form into the aqueous solution. Thus the content of Cl^- in water can be determined by measuring the ⁶⁰Co activity change between the two phases. The detection limit of the proposed procedure can reach 0.05ppm Cl^-.

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Ruthenium(III) reacted with O, O′-diethyl dithiophosphate(dtp^-) in a hot hydrochloric acid solution and gave a red complex, [Ru(dtp)₃], which could be extracted into chloroform. The spectrum of the extracted complex was affected by experimental conditions such as reaction temperature, reaction time, hydrochloric acid concentration and dtp^- concentration. The calibration graph for ruthenium(III) was linear over the range of (0.17-5.2)×10^-4mol dm^-3 ruthenium(III) under the condition of 6mol dm^-3 hydrochloric acid, 0.1mol dm^-3 dtp^- and heating at 60°C for 15min. The molar absorptivity at 510nm was 2.18×10³cm^-1 mol^-1 dm³ and the relative standard deviation was 1.5% (12runs) for 3.5×10^-4mol dm^-3 ruthenium. The ions which interfered severely were Mo(VI), Cu(II), Pb(II), Bi(III), Tl(I), In(III), Te(IV), Cd(II), V(V), Hg(II), Ag(I), Co(II) and NO₂^-.

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A sensitive and simple method for the determination of acid soluble and acid insoluble S-carbamyl groups in biological materials is presented. This method is based on the chemical properties of the S-carbamyl group, which is stable in acidic solution and liberates cyanate in alkaline solution, and those of the cyanate analyzer reported previously. Each sample solution was mixed with 20%(w/v) trichloroacetic acid (TCA) solution; the mixture was incubated for 1h at 37°C, followed by centrifugation. For the determination of acid soluble S-carbamyl group, the supernatant was added to an equal volume of 1.0M NaOH. Liberated cyanate was determined by cyanate analyzer. For the determination of acid insoluble S-carbamyl group, the precipitate was washed twice with 7%(w/v) TCA solution and then dissolved in 1.0M NaOH. After ultrafiltration, cyanate in filtrate was determined. The usefulness and practicality of the present method were verified by applications to the determination of S-carbamyl group in liver, plasma and erythrocytes of mouse.

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A gas chromatographic method is presented to determine traces of di- and tri-n-butyltin compounds in fish by use of an innovative clean-up cartridge. The cartridge used was packed with a moderately sulfonated low capacity cation exchange resin. The organotin compounds in fish tissue were extracted with hydrochloric acid-ethanol solution as their chlorides, transferred to an ethylacetate/hexane phase by liquid-liquid extraction, and the organic layer was concentrated with a rotary evaporator. The organotin chlorides were trapped on the resin by passing through the cartridge. The sampled cartridge was washed successively with ethanol, water and sodium chloride solution. The trapped organotin compounds were converted to their hydrides by passing a sodium borohydride ethanol solution through the cartridge, and these hydrides were eluted with 1/1 hexane/ethanol. The eluted organotin hydrides were extracted with hexane by shaking the eluate with water and hexane. The hexane layer was subjected to gas chromatographic separation, and identified by mass spectroscopy. The di- and tri-n-butyltin compounds in a fish sample could be determined as their chlorides with 2.7-4.8% relative standard deviations in the range 0.1-2.0μg/g. The detection limits of di- and tri-n-butyltin compounds as their chlorides were 3ng/g and 8ng/g for 10g of the sample.

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A sensitive and specific method for the analysis of oral hypoglycemic biguanides, metformin, buformin, and phenformin, was developed by use of high performance liquid chromatography (HPLC) with fluorometric detection. These biguanide drugs are converted to 2-alkylguanidino-1H-phenanthro[9, 10-d]imidazole derivatives by pre-column fluorescence labeling with 9, 10-phenanthraquinone (PQ) in an alkaline medium. The derivatives are separated on a reversed′phase column with 0.1M phosphate buffer (pH 2.5) containing 75 (v/v)% acetonitrile. Monosubstituted guanidines which exist in biological fluids also react with PQ in the same reaction conditions as the biguanides to form a fluorescent product, 2-amino-1H-phenanthro[9, 10-d]imidazole (API). However, they do not interfere with the analysis of the Biguanides in the elution system. The lower detection limits of biguanides added to serum are 0.2ng for metformin and 0.4ng for both buformin and phenformin, per 10μl of injection volume. The recoveries of 0.1μg biguanides added to 0.5ml of serum are in the range 96-102%.

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Described is a high performance liquid chromatographic method using fluorescence detection for the simultaneous determination of 5-fluorouracil and 5-fluoro-2′-deoxyuridine in human serum. After extraction with ethyl acetate from serum, these compounds and 5-chlorouracil (internal standard) are converted into the corresponding fluorescent derivatives by reaction with 3-bromomethyl-6, 7-dimethoxy-1-methyl-2(1H)-quinoxalinone in the presence of potassium hydrogen carbonate and 18-crown-6 in acetone. The derivatives are separated by reversed phase chromatography on a Radial Pak C₁₈ cartridge, with stepwise elution using aqueous 35 and 50% (v/v) methanol. The detection limits for 5-fluorouracil and 5-fluoro-2′-deoxyuridine added to serum are 12.5ng (95pmol) and 25ng (63pmol) per ml of serum, respectively, at a signal-to-noise ratio of 5. This method permits the determination of 5-fluorouracil in serum (0.1ml) from a healthy volunteer and a stomach cancer patient administered 5-fluorouracil intravenously.

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In this study the effect of nickel as a modifier on the spectral line intensities of As, Sb and Hg in d.c. arc was investigated. As a result of nickel addition into the sample, spectral line intensities of the elements decreased at low current strengths and increased at higher current strengths. It was concluded that the effect of nickel on As, Sb and Hg is due to the formation of thermally stable compound between nickel and the element to be determined.

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