"Synthetic analytical chemistry: Analytical chemistry with the aid of synthetic organic chemistry" is proposed by the present author as a new field of analytical chemistry. Such chemistry is developing on the basis of investigations of π-electron systems such as non-benzenoid aromatics (e.g. annulenes) or conjugated polyene and polyyne systems. Various kinds of organic reagents for analyses (ultraviolet/visible and near-infrared absorption, fluorescence, chemiluminescence and new silica gel column packings for high-performance liquid chromatography) were developed and applied to the analyses of many biomaterials. In this paper, synthetic analytical chemistry is illustrated mainly by the author′s own studies.

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The stability constants (β^NB₁(M)/mol^-1dm³) of 1:1 complexes of M⁺(=Li⁺, Na⁺) with 1, 3-bis(8-quinolyloxy)propane (IV), 1, 4-bis(8-quinolyloxy)butane (V) and 3, 3-bis[(7-methyl-8-quinolyloxy)methyl]oxetane (VI) were determined by ion- transfer polarography in water-saturated nitrobenzene (NB) at 25°C. Their logarithmic values were on the order of VI (4.6)<V(5.7)<IV(7.4) for M=Li and VI(3.9)<V(4.5)<IV(5.7) for M=Na. This order shows that the stability of the Li⁺ and Na⁺ complexes significantly increases when the carrier can form a four-coordinate structure similar to that of a tetradentate 14-crown-4 in their complexes. The potentiometric selectivity coefficients (k^pot_LiNa) of IV-VI for Li⁺ against Na⁺ were calculated based on the β^NB₁(M)-values using the equation log k^pot_LiNa=0.70+log[β^NB₁(Na)/β^NB₁(Li)], and the resultscompared with those previously described for other bis(8-quinolyloxy)propane derivatives.

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Aqueous micellar solutions of octyl-β-D-thioglucoside (OTG) were separated into two phases upon addition of polyethylene glycol 6000 (PEG). In this polymer-induced phase separation, one phase was an aqueous phase in which PEG was retained; the other was a surfactant-rich phase into which pyridylazophenols and their three metal chelates (nickel(II), zinc(II), and cadmium(II)) were extracted. Their distribution constants were highly dependent upon the PEG concentration and the nature of the metal chelate. This observation provides a possibility of controlling the extraction selectivity in polymer-induced phase separation.

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Fourteen water-miscible polar solvents were investigated for the separation from their aqueous solutions by salting-out using sodium chloride (4mol dm^-3). The following solvents showed the phase separation: acetone, acetonitrile, 1, 4- dioxane, tetrahydrofuran, 1-propanol, and 2-propanol. The chemical properties of the separated organic solvents were determined by measuring E_T(30)(=1.196×10⁵/λ (kJmol ¹)) and D_II.I(=1.196×10⁵(λ_II^-1-λ_I^-1)(kJ mol^-1))values from the spectral change of 2, 6-Biphenyl-4-(2, 4, 6-triphenylpyridinio)phenolate (DTP) and bis(1, 3-propanediolato)vanadium(IV) (VO(acac)₂), where λ, λ_I, and λ_II denote the absorption maximum wavelengths (nm) of DTP and VO(acac)₂. Solvent properties of acetone, acetonitrile, 1, 4-dioxane, and tetrahydrofuran were dramatically altered by the salting- out. Acceptability of the phase-separated solvents increased due to the dissolution of water molecules having large acceptor numbers. The ion-pair complex of tris(1, 10-phenanthroline)iron(II) chloride was easily extracted into the phase-separated acetonitrile by the salting-out. Some metal chelates of 1-(2-pyridylazo)-2-naphthol (Hpan) and 8- quinolinol (Hox), 5, 10, 15, 20-tetraphenylporphyrin (H2tpp), and ionic species (H₂ox⁺, ox^-, and H₄tpp²⁺) were also extracted into 1, 4-dioxane. The raised donor and acceptor abilities of the phase-separated solvents allowed application to solvent extraction.

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A preconcentration method is described for a flow-injection spectrophotometric determination of phosphate at the ng g^-1 level in sodium chloride. Coprecipitation and flotation were successfully achieved in 200ml of a 30%(w/v) sodium chloride solution at pH 8.5, with flocculent hydrated aluminum oxide precipitates (10mg as aluminum), 6mg of sodium oleate and 2mg of sodium dodecylbenzenesulfonate. Recoveries greater than 95% of phosphate were obtained with preconcentration coefficients higher than 103. The time required for the entire procedure was ca. 70min.

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A calibration method for determining the nitrogen content in steel by a thermo-conductimetric method after fusion in the current of an inert gas is proposed. In this calibration method, a pure chemical substance whose nitrogen content can be calculated based on its molecular weight is used as a calibrant. The nitrogen recovery and thermostability of 9 chemical substances in the fusion procedure were investigated; it was found that potassium nitrate is the most suitable as a calibrant. The results of analysis of 9 steel samples of certified reference materials demonstrate that the proposed calibration method is applicable to determination of nitrogen contents between 0.001% and 0.5%.

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Poly(3-methylthiophene)/polypyrrole bilayer-coated carbon fiber microcylinder electrodes were prepared by electropolymerization of the respective monomers. The voltammetric characteristics of the electrodes for dopamine (DA) and ascorbic acid (AA) in phosphate buffer saline (PBS) solutions (pH 7.4) were studied. The bilayer-coated electrodes exhibited highly enhanced electrochemical reversibility for the AA oxidation. Quasi-steady-state cyclic voltammograms obtained at 10mV/s had half-wave potentials at-50 and +125mV vs. SCE for AA and DA, respectively, in PBS solution. It has been demonstrated the bilayer-coated electrodes can be used for simultaneous determination of DA and AA in concentrations higher than 3μM and 50μM, respectively, by differential pulse voltammetry.

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A tris(2, 2′-bipyridine)ruthenium(II)/Nafion-modified Pt gauze electrode, where CO₂ was generated by oxidation of substrates, was combined with a CO₂ sensor. The combined sensor responded most effectively to oxalate among the organic acids examined. The response to oxalate was enhanced by use of a doubly-piled, modified Pt gauze electrode. The most suitable applied potential was +0.95V vs. Ag/AgCl; the stationary response was attained in 10min after the potential application. The response to 0.5mM oxalate was reproducible within 3% on 10 repeated runs and remained virtually unchanged over 10 days. The calibration curve for oxalate was linear in the concentration range of 0.1 to 5mM, and the detection limit was 0.05mM (S/N=3).

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A poly(vinyl chloride) membrane electrode that is highly sensitive and selective for zinc ions has been developed by using tetrabutyl thiuram disulfide neutral carrier. This electrode incorporated the ionophore along with o-nitrophenyloctyl ether as a plasticizing solvent mediator and potassium tetrakis(p-chlorophenyl)borate as anion excluder; it exhibited a linearity range of 10^-1-10^-6M with a Nernstian slope of 28.0mV per decade at 25±1°C. The membrane electrode showed a good response to zinc ions in the useful pH range of 3.5 to 6.5, where interferences arise only from a few transition metals such as Cu^II and Pb^II.

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Four macrocyclic polyether derivatives of 1, 10-phenanthroline were synthesized and used as neutral carriers for preparing poly(vinyl chloride) (PVC) membrane electrodes to sense primary amine species. The potentiometric response characteristics of the prepared electrodes were investigated. An electrode sensitive to benzylamine as a model analyte showed a linear response range of 1.0×10^-5 to 0.1mol dm^-3 with a detection limit 2.0×10^-6mol dm^-3 and a slope of 55.6mV/decade. The linear potentiometric response of the mexiletine-sensitive electrode was 6.0×10^-6 to 0.1mol dm^-3, and the detection limit was 8.0×10^-7mol dm^-3 with a slope of 58.0mV/decade. The transfer behavior of the amine and ammonium species through an organic phase was investigated by means of a bulk liquid-membrane transport experiment. The relationship between the potentiometric response characteristics of the prepared electrodes and the transport characteristics of the membranes has been studied. The mass-transfer rates of the test species facilitated by the macrocyclic polyether derivatives of 1, 10-phenanthroline were determined, and the following sequence was found: benzylamine>ethylamine>tetraethylammonium>triethylamine>diethylamine. This was exactly the potentiometric selectivity sequence of the membrane electrodes prepared by using these carriers.

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A new poly(vinyl chloride) matrix optical sensing membrane for the determination of iodine, based on reversible fluorescence quenching of fluoranthene, has been developed. The optimum membrane contains 2-9mg of fluoranthene, 50mg of PVC and 100mg of bis(2-ethylhexyl)phthalate. With the optimum sensing membrane described, iodine in sample solution from 1.60×10^-5-8.11×10^-3mol l^-1 can be determined. Besides a high reproducibility of the optical signals, a very short response time of less than 40s is realized. The membrane has good selectivity, except for Fe³⁺ and Bi³⁺, and other common ions in foodstuff do not interfere. The standard addition method has been used for the determination of iodine in table salts with satisfactory results.

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The design of an enzymatic biosensor based on the use of immobilized glucose oxidase is described for the determination of glucose in blood serum and undiluted whole blood. Measurements in whole blood with RSD=0.3% are possible due to the use of an outer polypropylene membrane wetted with a mixture of various polyoxyethylene ethers (Triton X-100).

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A new and simple procedure has been developed for the determination of fructose, in which only a sodium metaborate solution is used for titrating the fructose solution. Sodium metaborate forms boric acid and sodium hydroxide by hydrolysis. The boric acid reacts with fructose to form a fructose-boric acid complex, which is then neutralized with sodium hydroxide. Namely, the boric acid used to form the complex and the sodium hydroxide used to neutralize it are generated in the same quantity and simultaneously by the addition of sodium metaborate. The present method was compared with the Somogyi′s method. The F test revealed no significant differences between the two methods at the 95% significance level.

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An investigation concerning the role of carbon tetrachloride, which is usually contained in the catholic reagents used for Karl Fischer coulometric titration, is described. Carbon tetrachloride is reduced in the cathode to produce an electrolyte (chloride ion), and reduces the consumption of the electrolyte (diethanolamine methylsulfonate). It therefore slows down any drop in the electric conductivity of the catholic reagents. Further, it represses the production of the reducing sulfur compound from sulfur dioxide (present in the form of methylsulfonate) and prevents its transfer to the anode through the diaphragm. This results in a high water-measurement capacity of the catholic reagents as well as accurate water-measurement values.

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A method is described which combines radiotracer techniques with paper electrophoresis to investigate the optimal decomposition conditions for zinc and selenium in rice leaf and grain samples. After administration of the respective nuclides of ⁶⁵Zn and ⁷⁵Se solutions to the rice, samples of the tested rice are harvested and decomposed with a nitric and sulfuric acid mixture. The completeness of decomposition is investigated by measuring the respective radionuclide- containing species in the decomposed samples by electrophoretic analysis. The results indicate that the Se-containing rice samples are more easily decomposed than those containing Zn under our conditions. Different decomposition effects are observed between a nitric and sulfuric acid mixture and one which includes hydrogen peroxide. Decomposition may be connected with the analytical error.

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A flow injection analysis system for the determination of glycerol has been developed which incorporates a Clark-type oxygen electrode and an enzyme reactor packed with Sepharose 4B on which glycerol dehydrogenase and NADH oxidase are co-immobilized. The response of the system depended on the concentration of flavine adenine dinucleotide (FAD) added into the carrier solution [0.1M glycylglycine-KOH buffer (pH 9.2) containing 30mM ammonium sulfate]. A linear relationship between the glycerol concentration and the response current in the presence of 60μM FAD was observed over the 0.1-1.5mM range. The sampling frequency was about 25 samples/h at a flow rate of 0.5ml/min, and the relative standard deviation was 0.65% at 2.5mM glycerol level (n=10). Application of this system to commercial white and red wines gave satisfactory results compared with the F-kit method. No sample pretreatment was necessary other than dilution.

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A procedure is presented for determining isoprenaline (10^-7-10^-4M) in a flow injection system using chemiluminescence detection resulting from the reaction of isoprenaline with 10, 10′-dimethyl-9, 9′-biacridinium dinitrate (lucigenin) in aqueous solution of potassium hydroxide as a carrier stream. The logarithmic calibration curve was linear over the range from 1×10^-7M to 1×10^-4M. The effects of some analytical conditions on the chemiluminescence yield were investigated. The RSD at 1×10^-4M isoprenaline is 0.9% (10 replicates). The method is directly applicable to aqueous solutions of isoprenaline injection (1mg/5ml).

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A sulfur chemiluminescence detector (SCD) was applied to measuring the total sulfur content. A non-stationary phase column was used in a GC-FID connected to the SCD in order to measure the total sulfur content without separating it. It was revealed that interference from hydrocarbons could be eliminated by optimizing the combustion condition of the FID burner. A calibration curve was obtained independent of the types of sulfur compounds. The experimental results are in good agreement with those obtained with conventional methods.

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Liquid chromatography/atmospheric pressure chemical ionization mass spectrometry was used to determine vitamin D₃ and its analogs. Vitamin D₃ and its analogs were separated on a reversed phase ODS column. The eluent was fed into the atmospheric pressure ionization interface and vitamins were then quantitated in the selected ion monitoring mode. The detection limit of vitamin D₃ and its analogs were ca. 0.5ng (on-column) at a signal-to-noise ratio of 2. This method was used to determine vitamin D₃ and D₂ in multi-vitamin tablets. The flow injection mode was also effective for the determination of VD₃ in multi-vitamin tablets.

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The isocratic elution of serum albumin on a column containing N-methylpyridinium polymer was investigated and compared with the gradient elution reported previously. Separation of mercaptalbumin and nonmercaptalbumin was markedly affected by the pH, buffer system and salt concentration in the eluent. Good peak resolution of mercaptalbumin and nonmercaptalbumin was obtained with tris (hydroxymethyl)aminomethane-acetic acid buffer (pH 7.0) containing sodium acetate. This method was applied to the analysis of human serum: f_HMA (human mercaptalbumin fraction in albumin) was determined with a high precision.

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A rapid and simple preconcentration method by selective adsorption using activated carbon as an adsorbent and acetylacetone as a complexing agent is described for the determination of trace amounts of indium by graphite-furnace atomic absorption spectrometry. The indium-acetylacetonato complex is easily adsorbed onto activated carbon at pH 6.0-8.0. After the activated carbon phase, the adsorbing indium-acetylacetonato complex is separated and dispersed in 5ml of a 2%(v/v) glycerine solution containing 700μg of palladium. The resulting suspension of activated carbon is introduced directly into the graphite-furnace atomizer. The detection limit was 0.025μg/l(s/n=3), and the relative standard deviation was 4.0-5.0% at 1.0μgIn/100ml (n=10). This method was applied to the determination of indium in water samples and proved to be a useful technique for the preconcentration of trace amounts of indium in water samples.

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Analytical performance of mixed gas inductively coupled plasmas (ICP) of argon-nitrogen binary and argon-helium- nitrogen ternary system was investigated for seven elements (Mg, Ca, Ba, Zn, Cd, Fe, and Y) having different ionization potentials, to yield the following. (1) In argon-nitrogen mixed gas ICPs, one should select higher flow rates of the carrier gas than in the argon ICP to obtain the appropriate signal-to-background ratio (SBR). (2) The ternary mixed gas plasmas yield better operating conditions regarding the SBR, because helium suppresses any increase in the background level caused by the nitrogen addition.

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Transition metallic impurities in high-purity Be for a window of the solid state detector (SSD) of a commercially available total-reflection X-ray fluorescence (TXRF) analyzer were determined by the use of ICP-MS analysis. From this analysis, 150μg/g of Fe and 100μg/g of Ni were detected. Other impurities were less than 55μg/g. In the determination of trace metallic impurities (of the order of 10¹⁰ atoms/cm²) on Si wafer surfaces by TXRF, X-ray fluorescence, such as Fe K_α and Ni K_α, are known to be observed, even if these elements do not actually exist on the surface. These spurious peaks appear when the primary beam of W L_β radiation satisfies the Bragg condition and the
diffracted beam is detected by SSD. From our investigation, impurities in Be were found to be one of the origins of this phenomenon, because the diffracted W L_β radiation which is impinged into the SSD through the Be window excites the impurity in the window.

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It was found that the atomic vapor temperature of Se increased unusually in the analysis of Se added with Pd as the matrix modifier. To make an advanced study on this phenomena, and to lessen the interference, the (effective) atomic vapor temperature of As was measured by the two-absorption line method, and its relation to matrix modifiers was studied by using a multi-channel atomic absorption spectrometer. The atomic vapor temperature of As was measured by referring to the atomic vapor temperature of Pb in the furnace. The results are discussed along with the phase diagrams of As- alloys. In the presence of Cu or Co, it was presumed that As was atomized before formation of intermetallic compounds. In the presence of Pd or Ni, atomization of As began near the melting point of intermetallic compounds. An unexpectedly higher temperature of As atomic vapor was observed in the case of the rapid atomization. The atomic vapor temperature rose higher than one would have expected. Addition of potassium permanganate effectively reduced the unexpected temperature increase, and allowed a clear absorbance profile of atomization for As analysis of urine to be obtained.

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Chlorpromazine hydrochloride (CP) was measured with octacosane (OC) as an internal standard using a gas chromatograph/mass spectrometer (GC/MS). The integrated intensities were determined by mass chromatograms of many mass-to-charge ratios (m/z values) for each CP and OC. The intensities of the CP were then divided by each intensity of the CP; many intensity ratios were determined. In a multivariate analysis, the intensity ratios having a good correlation were firstly selected from all of the intensity ratios with quantification IV. A principal component analysis was then carried out using the selected intensity ratios; several principal components were determined. Furthermore, in consideration of the eigenvalues for each principal component, unknown concentrations were determined based on the principal component scores. The calculated concentrations of the CP agree well with theoretical concentrations compared with such conventional quantitative methods as the method of least squares or a multiple-regression analysis. A more accurate determination was made possible by the multivariate analysis.

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Thallium ion-selective electrodes based on PVC and five kinds of thiaethers are described. Although a PVC membrane electrode containing 5.1w/w% 1, 4, 8, 11-tetrathiacyclotetradecane (TTCT) plasticized by DOP (61.5w/w%) showed good performance for Tl⁺ sensitivity, potassium ion did not interfer. However, electrode containing other macrocyclic thiaethers do not show a Nernstian response to thallium activity. The size of the macrocyclic ring and a hydrophilic group introduced into the macrocyclic thiaether influenced the Nernstian slope as well as the linear activity range of the emf response. The additive effect of a lipophilic salt, potassium tetrakis(p-chlorophenyl)borate (KTpCLPB), in the membrane with respect to Tl⁺ selectivity was also observed.

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