The use of thermal analysis as a method for material characterization is increasing, particularly in the development of new materials. This review describes three of the analytical techniques within thermal analysis: differential scanning calorimetry (DSC), thermomechanical analysis (TMA) and dynamic mechanical spectrometry (DMS). DSC and TMA are the traditional thermal analysis techniques, and have gained wide acceptance for material characterization. Specific heat capacity measurements using the DSC and thermal expansion coefficient measurements using the TMA are discussed. This review also includes a discussion of the DMS as a newly added technique in thermal analysis and its application to polymers.

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Aqueous solutions of cationic micellar hexadecyltrimethylammonium hydroxide (CTAOH) and nonionic micellar polyoxyethylene(23) dodecanol enhanced the intensity of maximum chemiluminescence (CL) light emission from the reaction of 10, 10′-dimethyl-9, 9′-biacridinium dinitrate (lucigenin) with catecholamines. In contrast, a lowering of the CL emission was observed in the presence of anionic micellar sodium dodecylsulfate. The best sensitivity was achieved in micellar CTAOH: logarithmic calibration curves of adrenaline, dopamine and noradrenaline were linear over the range from the detection limit of 1×10^-8, 3×10^-7 and 5×10^-7M up to 1×10^-4M, respectively. In the presence of micellar CTAOH, improvements in the sensitivity by factors of 1.6-10 were observed relative to that in water. The relative standard deviation was 2.5% in the micellar media.

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The interactions of cationic porphyrin, tetrakis(4-N-methylpyridyl)porphine (H₂TMPyP), with 5′-adenosine triphosphate (ATP), 5′-adenosine diphosphate (ADP), 5′-adenosine monophosphate (AMP), adenosine (A), adenine (AN) and metal complexes of ATP were evaluated by UV-VIS and ¹H-NMR spectroscopy at 25°C and an ionic strength of 0.1mol dm^-3 (NaNO₃). The formation constants (log K/mol^-1 dm³), defined as L+H₂TMPyP_??_L(H₂TMPyP), were found to be 2.92±0.06, 2.92±0.16, 2.59±0.07, 2.20±0.07, 2.10±0.09, 2.83±0.03, 2.93±0.04 and 2.80±0.07 for L=ATP^4-, ADP^3-, AMP^2-, A, AN, Mg(ATP)^-2, Ca(ATP)^2- and Ni(ATP)^2-, respectively. The binding of magnesium(II), calcium(II) or nickel(II) to ATP does not affect the formation of the molecular complex of H₂TMPyP with ATP. The addition of ethanol or the protonation of an adenine base, however, destabilizes the molecular complex. The predominant factor (75%) for stabilization of the molecular complex is a hydrophobic interaction between the porphyrin plane and the adenine base; the remaining factor (25%) is an electrostatic interaction between the negatively charged phosphates of nucleotides and the positively charged N-methylpyridyl groups of H₂TMPyP. A hydrophobic interaction was also confirmed by 2-D ¹H-NMR experiments, in which large upfield shifts were observed for the chemical shifts of H-2 and H-8 protons of adenine base, and H-1′ of ribose.

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A capillary gas chromatographic method, based on trifluoroacetylated polyols, was applied to a study of urinary polyols in normal subjects and in patients with various diseases. Polyol excretion patterns during fasting periods and circadian variations were studied in normal subjects. Twenty-four hour urine sample sets of normal subjects showed almost constant polyol profiles, suggesting the existence of a polyol regulation system in the body. Excretion patterns of 10 polyols were studied in 100 specimens of 24-h urine samples from patients hospitalized with various diseases. Polyol profiles showed patterns characteristic of pathological states of the diseases: such as diabetes mellitus, chronic renal failure, and chronic liver diseases. The possibility of diagnosis of several diseases by urinary polyol profiles is presented.

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A capillary gas chromatographic method for urinary polyol profiling analysis was applied to a study of urinary polyols in patients with chronic liver diseases. There was no statistically significant difference in any urinary polyols between the groups with and without glucose infusion. Ribitol, xylitol and sorbitol in patients significantly increased, and arabitol significantly decreased compared with the amounts from normal subjects. It is striking that the decrease of arabitol and the increased abnormal incidence of mannitol and sorbitol were well correlated with the severity of chronic liver diseases according to the Child-Turcott Classification. Urinary polyol profiling analysis may be useful in assessment of hepatic functional reserve.

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A high performance liquid chromatographic method with on-line postcolumn fluorescence derivatization is described for a simple and sensitive determination of opioid peptides, including enkephalins in rat brain. The peptides were separated on a reversed-phase column (Asahipak ODP-50) by gradient elution of acetonitrile in the mobile phase containing a borate buffer (pH 10.0). They were then automatically converted into fluorescent derivatives by reactions with hydroxylamine, cobalt(II) ion and borate. This derivatization was specific for N-terminal tyrosine-containing peptides. It was successfully used not only for the simultaneous quantification of the endogenous seven opioid peptides at the picomole level in brain tissue, but also for their identification by means of enzymatic degradation using carboxypeptidase A and trypsin. The detection limits (S/N=3) for the synthetic peptides were 0.5-1.5pmol in the injection volume.

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dl-1, 2-Diphenylethylenediamine was found to react sensitively in an alkaline solution with 3, 4-dihydroxymandelic acid as well as other catechol compounds and 4-hydroxy-3-methoxyphenyl compounds to yield fluorescent products. By using this reaction, a postcolumn fluorescence derivatization high performance liquid chromatography of the acidic metabolites of catecholamines (3, 4-dihydroxymandelic acid, 3, 4-dihydroxyphenylacetic acid, vanillylmandelic acid and homovanillic acid) in human urine was established. These compounds were separated on an anion-exchanger column (TSK-gel DEAE-2SW) and subjected to derivatization involving coulometric oxidation followed by a fluorescence reaction with the named reagent. The detection limits (S/N=3) for the acidic metabolites in urine were 15-30fmol in a 100-μl injection volume.

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Spatially resolved noise amplitude spectra of emission signals from an inductively coupled plasma (ICP) were obtained by moving the ICP source along the vertical and horizontal axes. In the noise amplitude spectra, an audio frequency (AF) noise was observed at a frequency of ca. 280Hz. The noise frequency was-independent of the spatial positions of the ICP and coincided with that shown in high-speed motion pictures of the plasma. By putting a 100mm extension tube on the plasma torch, the AF noise disappeared in high-speed motion pictures as well as in the noise amplitude spectra. These results confirm that the AF noise observed under our experimental conditions is due to vortices formed at the boundary region as the plasma gas flows from the ICP torch into the surrounding static atmosphere.

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The crystal structure of α-hafnium bis(monohydrogen orthophosphate)monohydrate, an inorganic ion-exchanger, was solved by the X-ray Rietveld technique utilizing synchrotron radiation (SR) as the X-ray source. This compound is monoclinic with space group P2₁/n and cell parameters a=9.0142(1), b=5.25665(5), c=15.4768(2)Å ??_ and β=101.636(1)°. Intensity data were collected by a capillary method with monochromatic X-rays of wavelength λ=1.49977(1)Å. The results were compared with those obtained by a conventional X-ray source and the advantages of SR in Rietveld analysis were verified. Despite the difference in the Li-ion exchange behavior between the α-hafnium phosphate and the α-zirconium phosphate, both phases were found to be isostructural with each other.

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Lanthanum(III) has been found to catalyze the reaction of trithionate with sulfide. The effects of reaction temperature and time as well as the pH and amounts of sulfide and lanthanum(III) were investigated; the optimal conditions for trithionate to be stoichiometrically converted into thiosulfate were established. The excess sulfide used for sulfidolysis of trithionate was completely removed with a suspension of freshly precipitated zinc carbonate hydroxide. Then, the formed thiosulfate was allowed to react with a given amount of iodine; excess iodine was measured spectrophotometrically as triiodide. The proposed method was successfully applied to the determination of trithionate, thiosulfate and sulfide mixed in various ratios and gave a relative standard deviation of 1.4% for trithionate at the 1.00μmol level in the presence of thiosulfate (2.00μmol) and sulfide (1.00μmol).

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2-Diethylamino-4-hydroxy-5-nitroso-6-aminopyrimidine (EHNA) is synthesized and used for the spectrophotometric determination of Iron(II). EHNA reacts easily with Iron(II), copper(II) or nickel(II) to form water-soluble complexes at pH 6.1. The iron(II)-EHNA complex, once formed, is stable even at pH 10.3, while the copper(II) and nickel(II) complexes are decomposed at this pH. The Iron(II)-EHNA complex is extracted into an organic solvent such as isopentyl alcohol. The molar absorptivity of the iron(II) complex in an aqueous solution is 3.0×10^-4l mol^-1 cm^-1 at 660nm. The molar ratio of iron(II) to EHNA in the complex is 1:3, according to the continuous variation method. This method has been satisfactorily applied to the determination of iron in various samples, such as leaded brass, copper-nickel and magnesium-aluminum alloys.

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A solvent-extraction Spectrophotometric method for the determination of anionic surfactants in water was developed with -(4-N, N-dimethylaminophenylazo)-2-methylquinoline (MQ) by batchwise and flow-injection techniques. The ion associates of MQ with anionic surfactants extracted into an organic phase showed a blue shift of the maximum absorption wavelength; their molar absorptivities were 4.5×10⁴l mol^-1 cm^-1 at 560nm. In the batchwise method, a 40-fold extraction concentration was possible. In the 20-fold concentration, the calibration graph was linear at concentration ranging from 1×10^-8M to 7.5×10^-7M of anionic surfactants, and the mean absorbances of the reagent blank and the 5×10^-7M anionic surfactant (dodecylsulfate : LS^-) were 0.024 and 0.518, respectively; the relative standard deviation for 10 measurements of 5×10^-7M LS^- was 0.28%. Foreign ions generally existing in river water did not interfere with the determination. This solvent-extraction spectrophotometric method was satisfactorily applied to a flow-injection method. The reagent MQ was recycled and repeatedly used at least for 7 months, and the efficiency of the reagent has not changed during at least this period.

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The concentration of sulfate ions in rain water was determined by a flow-injection method using a reaction column packed with barium chloranilate powder. Aqueous ammonium chloride (0.5%) containing 50% ethanol was used as a carrier at a flow rate of 1.9ml/ min. The chloranilate ion concentration, which corresponds to the sulfate ion concentration, in the carrier from the reaction column was monitored by a photometric detector at 530nm. Interferences by multivalent cations were eliminated with the use of a cation-exchange column inserted in the upper stream of the reaction column. The concentrations of sulfate ions in rain water (4-100ppm) were quickly determined (one sample per minute) with high reproducibility. The results agreed well with those obtained by the standard manual method.

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Plasticized PVC membranes incorporating conventional potassium-selective neutral ionophores and a neutral H⁺- selective chromoionophore have been used as reversible sensing devices for an optical determination of K⁺ activities in pH-buffered solutions. Dynamic range, reproducibility, response time, and selectivity of the new optode membranes are discussed. With this potassium-selective membrane, the reversible optical determination of total K⁺ concentration in human blood plasma is available. Results are compared to measurements with ion selective electrodes and flame photometry.

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The effect of complexing agents on the titration of chromium(VI) and copper(II) with iron(II) was studied. In general, iron(III) forms more stable omplexes than iron(II), so that the potential of the system Fe(III)/Fe(II) is lower in the presence of a complexing agent than in its absence. Thus the addition of a complexing agent increases the sharpness of the end point of titration with Iron(II). The presence of pyrophosphate improves the potential break at the equivalence point of chromium(VI) with Iron(II). The use of neocuproine together with pyrophosphate is very effective in the titration of copper(II) with Iron(II).

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The thermometric titration of copper(II) ions with triethylenetetramine was investigated. The apparent enthalpy change of the titration reaction varied over a wide range, even from exothermic to endothermic, depending on the reaction conditions, such as pH of sample and titrant solutions, species of buffer and coexistence of auxiliary reagent. In acetate buffer solution, this reaction was endothermic, and copper(II) ions could be titrated with error less than 0.5% of RSD even in the presence of other heavy metal ions. Furthermore, the sequential titration of copper(II) and zinc(II) ions was possible with error less than 0.7% of RSD when tartrate was added as an auxiliary reagent to get sharp end points. The methods were applied to the analysis of four samples of copper-based alloy. The analytical results agreed closely with those obtained by the JIS (Japanese Industrial Standard) method based on electrogravimetry.

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The relative concentration and composition of dissolved humic substances in the Oita River, Oita, were measured over a two-year period from 1988 to 1989 by chromatography with pH-gradient elution. The concentration during ordinary water runoff remained at a constant level during the winter months, but increased through April into the beginning of July to reach a value about 2.5-times higher than that in the winter. A sudden lowering was observed through the middle of July into August. The concentration during high flow above 80m³ s^-1 induced by rainfall increased with an increase in the flow rate; the maximal observed value was about 5-times as high as that during ordinary water runoff. The extent of the increase was greater for components eluting in a higher pH region than in a lower pH region. An imitative test suggested that scouring of autochthonous humic substances in bottom sediments of the river was one contribution to the concentration increase and the composition change. Thus, the chromatographic method employed permitted us to obtain detailed information concerning seasonal variations and violent rainfall-induced fluctuation.

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Color-changeable extractants for acids, acidophores, were synthesized and examined; they were 4-(N, N dimethylaminophenylazo)-pyridines and quinolines. The fundamental physicochemical constants for the acidophores and their ion associates were determined by spectrophotometry. The liquid-liquid distribution was carried out between an aqueous phase and a chloroform phase. A parameter of the extractability of the protonated cations of the acidophores and of several inorganic and organic anions as ion associates was determined on the basis of the assumption that the extraction constant of an ion association complex, log K_ex, is divided into a cationic and an anionic contributions, C and A, respectively. The order of the extractability of the anions was: Br^-<I^-<ClO₄^-<SCN^- <Pic^-<(Ethyl range)^-<C₁₂H₂₅-OSO₃^-. Anionic surfactants could be quantitatively extracted into chloroform with 4-(4-N, N-dimethylaminophenylazo)-2-methylquinoline: the molar absorptivity was 4.5×10⁴l mol^-1 cm^-1 at 560nm. The acidophores once used could be recycled and be used repeatedly.

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Dithiocarbamate-chitin (DTC-chitin) is synthesized by mixing chitin powder with carbon disulfide, 2-propanol and tetramethylammonium hydroxide in benzene. The DTC-chitin contains about 0.7% of sulfur, and the IR spectra of the DTC-chitin exhibit a small band at 1480cm^-1 which is assigned to N-C=S. This polymer sorbs silver and copper from acidic solutions in the range of 1M (mol dm^-3) nitric acid to pH 5.0, cadmium at pH 1.0-6.0, and cobalt and nickel at pH_??__2.5. On the other hand, untreated chitin sorbs these metal ions only at a pH above 7.0. The maximum flow rate for quantitative retention is 15ml min^-1 for 0.04ppm of silver, cobalt and copper. The metals retained on the column are eluted with dilute nitric acid containing thiourea or hydrogen peroxide and are determined by flame atomic absorption spectrometry.

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The coprecipitation equilibrium of lanthanoid(Ln(III)) ions such as La(III), Ce(III), Nd(III), Sm(III), Tb(III), Tm(III) and Lu(III) with calcium oxalate was investigated by a radiotracer method. The distribution ratio of Ln(III) between the solid phase of calcium oxalate and the aqueous phase containing trace amounts of Ln(III) ion was determined. It was found that the coprecipitation mechanism is an ion exchange of three Ca(II) ions with two Ln(III) ions. The equilibrium constants, K=[Ln³⁺]²_solid[Ca²⁺]³_aq/[Ln³⁺]²_aq, were determined for these 7 lanthanoid ions.

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The accuracy of nitron-method gravimetry for the determination of the purity of potassium nitrate and that of sodium nitrite was studied. The gravimetry of potassium nitrate was compared with that of nitric acid determined by an acidimetric coulometric titration. The concentration of nitrate ions left in the filtrate of the nitron nitrate precipitate was measured by ion chromatography. A method for the oxidation of nitrite ions to nitrate ions by permanganate ions was studied for the purpose of the application of the nitron-method to the determination of the purity of sodium nitrite. The small quantity of nitrate ions contained in sodium nitrite was determined by ion chromatography.

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