The enantiomeric isomers of organic compounds usually appear in the racemic form in synthetic reactions of the laboratory. However, each of the isomers must somehow be differentiated from the others in biosynthetic reactions, such as of proteins. This differentiation is possible in a bio-reaction because of a salt concentration of about 0.1mol/l NaCl and the presence of oxygen in the aqueous media of the reaction. Under these conditions, a magnetic field will differentiate the enantiomeric isomers. Experimental evidence shows that the above concentration is unique because it produces a kind of border for water structures. Also, amino acids interact differently with water due to differing hydrophilic properties. Finally, a salt solution of this concentration, together with oxygen, allows differentiation of the enantiomeric isomers of amino acids under a magnetic field. The results of this investigation suggest that the condition of the solution produces circumstances where each of the solute entities can be free from inter-solute interactions. This circumstance locates each solute entity in a fractional part of the solution which is equal to the quotient of the total volume of the solution divided by the total number of the solute ions. In this situation, all solutes are assumed to not interact, and accordingly, the characteristics of the solute can be distinguished. This fractional part of the solution has been termed the "molecular space". To determine what would happen when the enantiomeric isomers of amino acids were placed in a molecular space, nuclear magnetic resonance (NMR) and differential scanning calorimetry (DSC)measurements were taken in aqueous sodium chloride solutions (about 0.1mol/l NaCl) which held the enantiomeric isomers of amino acids. The results showed that the D-isomers form association with oxygen under magnetic field and the L-ones not. This suggests that the D-isomers are retained in the solution by complex formation with oxygen and only the L-ones can participate to the biosynthesis under the earth′s magnetic field. The presence of oxygen and a magnetic field applied to the isomers are the factors which allow the differentiation between the L- and the D-isomers.

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During the solvent extraction of cobalt(II) with acetylacetone, benzoylacetone, dibenzoylmethane, and benzoyltrifluoroacetone in toluene, oxidation of the metal ion was found only with acetylacetone. The oxidation was assumed to be caused by dissolved atmospheric oxygen in the organic solvent. The rate of oxidation was first order with respect to the acetylacetone concentration, and was nearly the same when the diluent was carbon tetrachloride. This oxidation was slowed down by the addition of trioctylphosphine oxide. The shape of the extraction curve of cobalt(II) with acetylacetone as a function of the hydrogen-ion concentration was different when the time for the two-phase agitation was one hour, one day, and one week. The reason for this is discussed from the standpoint of the slow oxidation of cobalt(II) and of the acetylacetone concentration in the organic phase.

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A "pH scanning technique" was introduced for the liquid-liquid extraction of metal chelates by high-speed stirring. The increase of pH in the aqueous phase containing phosphoric, boric and acetic acids as pH buffer reagents was controlled by addition of a 5M NaOH solution at the rate of 0.9ml/min. The relationship between pH change in the aqueous phase and the addition time of the NaOH solution was almost linear in the range of pH 2.5-11. The absorbance of metal complexes extracted into chloroform phase was recorded continuously after the separation of organic phase from the mixture of two liquids by use of a Teflon phase separator under the conditions of high-speed stirring. By the present method, copper(II), cobalt(II) and indium(III) were simultaneously determined in the range of 0.1-60μg with 8-quinolinol. The advantage of the present method was the separation of some metals having rapid-extraction rates from other metals having slower rates.

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A simple, sensitive and selective spectrophotometric method for the determination of cadmium at trace levels in various environmental samples is reported. The binary complex formed between cadmium(II) and N-hydroxy-N, N′-diphenylbenzamidine (HDPBA) is extracted with chloroform at pH 9.0±0.2 and shows a maximum absorbance at 400nm with a molar absorptivity of 1.96×104l mol^-1 cm^-1. The sensitivity of the binary complex was enhanced by adding 4-(2-pyridylazo)resorcinol (PAR) after extracting cadmium(II) with HDPBA at pH 9.0±0.2. The reddish-orange complex shows a maximum absorbance at 520nm with a molar absorptivity of 5.9×104l mol^-1 cm^-1. This method follows Beer′s law up to 1.6μg cm^-3 Cd. Various experimental parameters such as the effect of solvents, pH, time, temperature, concentration of the reagent and order of addition of reagents have been studied for establishing the optimum conditions for the determination of cadmium. The effect of diverse ions was examined; the results indicated that most of the common ions like Fe(III), Co(II), Ni(II), Cu(II), Mn(II), AI(III), V(V), Cr(III), Mg(II), Mo(VI), Sn(IV) and Bi(III) do not interfere. The detection limit of cadmium in this method is 0.05μg cm^-3. The relative standard deviation of the method for ten replicate measurements is ±1.4%. This method has been successfully employed for the determination of cadmium in various environmental samples.

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The equilibrium constants of some organophosphinic acids have been determined at 25°C by measuring the distribution ratio of the organophosphinic acid between an aqueous solution of ionic strength 0.05 and toluene as a function of pH for different concentrations of organophosphorus acid compounds. The distribution ratio of the organophosphorus compounds has been obtained by determining phosphorus by inductively coupled plasma-atomic emission pectroscopy. The data have been analyzed graphically, and numerically by the program LETAGROP-DISTR, in order to determine the dimerization constants K₂, the acidity constants K_a and the distribution constants K_D

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Capillary electrophoresis of alkaline-earth metal ions was examined with a UV-absorbing chelating agent. The metal1 chelates separated in a capillary were measured by on-column UV-absorptive detection. When ethylenediamine-tetraacetic acid (EDTA) was used as an chelating agent in a carrier solution (pH 9.2), the order of the migration time (t_m) of metal ions was as follows: Ba²⁺<Sr²⁺<Ca²⁺<Mg²⁺ (Be²⁺ could not be detected). These four ions were separated within 16min using a capillary (50μm i.d.) of 75-cm effective length (L_D) at an applied voltage of 30kV, and calcium and magnesium ions were separated within 4min using a 25-cm capillary at an applied voltage of 20kV. By using a 50-cm or 25-cm capillary, Ca²⁺ and Mg²⁺ in river, tap and underground water samples were determined; the detection limits of metal ions were about .10^-5M (1M=mol dm^-3), and the relative standard deviations for the determination of around 10^-4M of the metal ions were less than 2.0%. The method was also applied to the determination of Ca²⁺ and Mg²⁺ in a standard serum sample.

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The sample is decomposed with boiling 4M hydrochloric acid to convert sulfur into hydrogen sulfide, which is then transferred with a nitrogen stream to a continuously moving paper tape impregnated with lead(II) acetate. The resulting lead(II) sulfide on the tape is then measured by reflectance photometry at 555nm. The amount of sulfur (3-10μg) in steel can be determined with a relative standard deviation of less than 3% (n=3 to 7) within 10min.

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A potentiometric determination of the total water hardness by flow-injection analysis is proposed, which uses both a Cu²⁺ ion-selective electrode detector and a Cu²⁺-ion buffer stream comprising a Cu-EDTA complex and free EDTA. This method is based on potentiometric monitoring of the change in the free Cu²⁺-ion concentration in the buffer with a Cu²⁺ ion-selective electrode, caused by the reaction of Ca²⁺ and Mg²⁺ ions with free EDTA in the buffer. Chloride interference in the measurement of the Cu²⁺-ion concentrations with the Cu²⁺ ion-selective electrode was successfully eliminated by adding triethylenetetramine to the Cu²⁺-ion buffer. The total hardness of seawater samples could therefore be determined at a sampling rate of 30h^-1 and a relative standard deviation of 0.7%. The obtained results using the proposed method were in good accord with those obtained by conventional chelatometric titration.

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The sequence distribution of poly(neopentyl isophthalate-fumarate) was studied by high-resolution ¹H nuclear magnetic resonance (¹H-NMR). The ¹H-NMR signals of methylic and methylenic protons of the copolyester were split into five and six peaks, reflecting the linkages between neopentyl glycol (N) and two kinds of acids, i.e. isophthalic acid (I) and fumaric acid (F). All of the peaks were assigned and the dyad sequence (F-N-F, F-N-I, I-N-I etc.) distribution of poly(neopentyl isophthalate-fumarate) was clarified on the basis of the ¹H-NMR spectrum. This copolyester was found to be a random polycondensation type, though there was a large difference between I and F concerning the rate of esterification.

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Lanthanum(III) chromium(V) tetraoxide, LaCrO₄, was synthesized by a thermal decomposition method and characterized by X-ray photoelectron spectroscopy and ab initio molecular orbital calculations. The chromium(V) state in LaCrO₄ is stable in both air and vacuum. The electron binding energies, E_B, and Auger parameters, α, of Cr(V) and La(III) indicated that the covalency of the Cr-O bonds in CrO₄ tetrahedra is higher than that in CrO₆ octahedra of LaCrO₃, and that La(III) in LaCrO₄ is more ionic than in LaCrO₃. The results of ab initio molecular orbital calculations agreed with the measured characteristics, that is, the electrons are flowing from oxygen to Cr(V) and the covalency plays a significant part in the Cr-O bonds. This behavior of the Cr-O bond was considered to contribute to stabilizing CrO₄^3- tetrahedra.

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The sensitivity for the chemiluminescent (CL) detection of nucleosides and their derivatives was improved by using clinoptirolite chemically modified with cupric nitrate, Cu-Zeo. Cu-Zeo plays a key role as a solid medium for such so-called material exchangers as ion exchange between copper(II) coated on Cu-Zeo and nucleosides and their derivatives. The properties for material exchange were examined by a batch method in which Cu-Zeo(1.5g; particle size, 250mesh) was added into the analyte solution (100ml). Analytes were indirectly determined by the CL analysis of cupric ions eluted from the Cu-Zeo through the material exchange. For the CL detection of cupric ions, an FIA/CL system using a 1, 10-phenanthroline CL was employed. The lower limits of detection for analytes were improved by 42 times for adenosine (1.9pmol/20μl) and by 16 times for uridine-5′-diphosphate (5.5pmol/20μl), compared with those by our previous method.

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A method used to determine trace amounts of samples in aqueous solutions is proposed. Cobalt ion was extracted as a 1-(2-pyridylazo)-2-naphthol (PAN) complex into chloroform. The extract was filtered through an Empore silica-gel TLC plate (2.5cm square) having no backing material. Excessive PAN and other metal-PAN complexes were washed out through the TLC plate by filtering twice 5ml of chloroform. Using these procedures only the cobalt-PAN complex was concentrated on the surface of the TLC plate. The photoacoustic signal of the TLC plate was detected by using a He-Ne laser as a light source. A linear relationship was obtained between the concentration of cobalt and the photoacoustic intensities in the 0.1-20ppb range. A five-hundred-times concentration of Ni, Cu and Fe did not significantly interfere with the photoacoustic signal. The determination limit of cobalt when the sample volume was 100ml was about 0.15ppb.

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A sensitive and reliable method for the separation and characterization of bile acid N-acetylglucosaminides has been developed by precolumn labeling followed by high-performance liquid chromatography (HPLC) with fluorescence detection. The 3-N-acetylglucosaminides of unconjugated, glycine- and taurine-conjugated bile acids were derivatized into fluorescent esters through a primary hydroxyl group on the sugar moiety by treatment with 9-anthroyl cyanide in the presence of quinuclidine in acetonitrile. Subsequent separation into each 3-N-acetylglucosaminide was achieved by reversed-phase chromatography on a Cosmosil 5C₁₈ column using a 0.3% potassium phosphate buffer (pH7.0)/methanol (1:4, v/v) as a mobile phase. The derivatized 3-N-acetylglucosaminides were monitored by fluorescence detection (excitation wavelength 362nm; emission wavelength 470nm), the limit of detection being 100fmol. The chromatographic separation of 3- and 7-N-acetylglucosaminides of ursodeoxycholates is also described.

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3-Bromoacetyl-7-methoxycoumarin (I) was synthesized as a highly reactive fluorescent derivatization reagent for use in high-performance liquid chromatographic analysis. Compound I readily reacted with carboxylic acids in acetone at room temperature for 30min in the presence of potassium bicarbonate and 18-crown-6(Method A), or an anion-exchange resin (Method B) as catalysts to give the corresponding fluorescent carboxylic acid coumarinacyl esters(II_a-o). When lauric acid as a test sample was derivatized with I by use of Methods A and B, the detection limits were 0.4 and 0.5pmol per injection (S/N=3), respectively. These methods were applicable to the measurements of free fatty acids in human plasma (10-100μl). Method B used a weakly basic anion-exchange resin instead of catalysts so in Method A, so it would be useful for the simplification of derivatization.

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Eight novel 2-chloro-4-nitrophenyl maltotetraosides modified at the 6⁴- and/or 4⁴-position were synthesized for human pancreatic and salivary α-amylase substrates. In these compounds, 2-chloro-4-nitrophenyl O-[4, 6-di-O-(N-isopropyl)carbamoyl-α-D-glucopyranosyl]-(1→4)-bis[O-α-D-glucopyranosyl-(1→4)]-β-D-glucopyranoside (9) was rapidly hydrolyzed by the two amylases at a limited position to produce 2-chloro-4-nitrophenyl β-D-glucopyranoside. Taking advantage of the properties, 9 was found to be a good substrate for a human α-amylase assay using only β-glucosidase as a coupled enzyme.

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An on-column fluorometric derivatization method has been developed for the determination of polyamines using high-performance liquid chromatography. The system for the derivatization consisted of a single-plunger pump and a reversed-phase C₁₈ polymer column with a mobile phase of acetonitrile and alkaline borate buffer solution containing o-phthalaldehyde and N-acetyl-L-cysteine as derivatizing reagents. The polyamines injected onto the liquid
chromatograph are derivatized to fluorophores at the inlet of the column, followed by chromatography on the same column. Optimization of the liquid chromatography conditions led to a simple analytical method for the simultaneous determination of polyamines with high reproducibility and linearity. Application of this method to the determination of polyamines in food samples resulted in overall mean recoveries greater than 85% at fortification values of 20-200 μg g^-1 of each polyamine.

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The separation of organophosphorus pesticides by supercritical fluid chromatography was investigated using four packed columns and five fused silica capillary columns. Fourteen pesticides used worldwide were selected; the separation of as many species as possible with one injection was attempted by optimizing the column temperature and the pressure program. Among the packed columns used, an ODS column resulted in a favorable separation, enabling the simultaneous identification of 12 species. However, pesticides having strong hydrogen-bonding functional groups were either not eluted or eluted later. By using capillary columns the chromatographic peaks of these pesticides could be obtained, and various separation modes were possible with liquid stationary phases having different polarities. Also presented is information concerning the retention behavior of each organophosphorus pesticide.

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An analytical method for determining the total content of fungicides carbendazim (MBC, methyl benzimidazole-2-1yl-carbamate), benomyl (methyl 1-(butylcarbamoyl)benzimidazole-2-yl-carbamate) and thiophanate-methyl (dimethyl 4, 4′-(o-phenylene)bis(3-thioallophanate)) in water has been developed. The latter two are known to be converted to MBC in the environment. A water sample (100ml) was mixed with potassium dihydrogenphosphate and disodium hydrogenphosphate (pH 6.8±0.2) and then refluxed for 1h. By this reaction the fungicides were quantitatively converted to MBC. An aliquot (10ml) of the reaction mixture was injected into a high-performance liquid chromatograph equipped with a column-switching apparatus and a thermospray mass spectrometer. The detection limit was 0.02ppb equivalent as MBC. The recoveries of benomyl, carbendazim and thiophanate-methyl fortified in water at a fortification level of 0.05ppb ranged from 85 to 95%.

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