Norio Ichinose

High-performance liquid chromatography of 5,8,11,14,17-Eicosapentaenoic acid in fatty acids (C18 and C20) by labelling with 9-anthryldiazomethane as a fluorescent agent

Abstract A sensitive high-performance liquid chromatographic method using 9-anthryldiazomethane has been developed for the separation and determination of 5,8,11,14,17-eicosapentaenoic acid (EPA) from C18 and C20 fatty acids, with a view to its application to the HPLC determination of EPA in fish and human blood or serum and in plankton body fluid. The limit of detection of EPA is about 300 pg and the coefficient of variation is 2.1%.

Fluorescent high-performance liquid chromatography of folic acid and its derivatives using permanganate as a fluorogenic reagent

SummaryA fluorescent high-performance liquid chromatography (HPLC) analysis of folic acid (pteroylglutamic acid) and its derivatives using permanganate as a fluorogenic reagent has been developed. In the present work, the various analytical conditions in which the fluorogenic reaction with permanganate could be applied to the HPLC of folic acid in human serum, have been studied. The present method may be employed for the rapid clinical analysis of small amounts of folic acid (≥150 ppb), without interference from coexisting natural fluorophors; the precision of the present method for folic acid was 6.6% (n=6) (coefficient of variation).

Microanalysis of methotrexate by high-performance liquid chromatography using a fluorescence detector

Methotrexate (N10-methyl-4-aminofolic acid) has been determined by HPLC after oxidizing it with permanganate to a fluorogenic derivative. The detection limit has been 0.01 μg/ml. The method has been applied for the determination of methotrexate in blood serum of rats.

Application of High-Speed Liquid Chromatography using Solvent Extraction of the Molybdoheteropoly Yellow to the Determination of Microamounts of Phosphorus in Waste Waters*

ZusammenfassungMolybdoheteropolygelb wird mit Methylpropionat extrahiert. Eine Störung durch Silicium wird dadurch eliminiert, daß die entsprechende Si-Heteropolyverbindung nicht mitextrahiert wird. Mikromengen Phosphor können rasch und genau nicht nur in Abwasser, sondern auch in Flußwasser bestimmt werden. Die Nachweisgrenze liegt bei 0,5 ppm; der Variationskoeffizient beträgt 4,7%.SummaryMicroamounts of phosphorus are determined in waste water by HPLC. The method is based on the solvent extraction of molybdoheteropoly yellow with methyl propionate. The corresponding silicon compound is not extracted into this solvent. Thus, the interference by silicon is excluded. Microamounts of phosphorus can be determined not only in waste water but also in river water rapidly and exactly. The limit of detection is 0.5 ppm, the coefficient of variation 4.7%.

Determination of antimony in solder alloy by hydride generation followed by graphite furnace atomic absorption spectrometry

ZusammenfassungAntimon wurde nach diesem Verfahren in Lotlegierung NBS (SRM 1276) bestimmt. Die Stibine wurden in einer horizontalen Glasröhre erzeugt, die gekörntes Natriumborhydrid enthielt. Der Argonfluß betrug 1, 2–1,3 l/min, die Atomisierungstemperatur 2300° C und die Konzentration an Säure 1,2–1,5 M. Die starke Unterdrückung des Sb-Signals durch Ni, Co und Cu konnte erfolgreich mit Hilfe von 1,10-Phenanthrolin verhindert werden. Die Nachweisgrenze lag bei 1,2 ng, die Präzision betrug 4–5%. Die benutzte Reduktionsröhre ist sehr einfach und kann an alle Typen von Graphitöfen angeschlossen werden. Das Verfahren läßt sich auch zur Quecksilberbestimmung [1] einsetzen.SummaryAntimony was determined in solder alloy (NBS; SRM 1276) by a combination of hydride generation with reducing tube, graphite furnace atomization and atomic absorption detection. Stibines were generated in a horizontal glass tube, in which a pellet of sodium borohydride was placed. 1.2–1.3 1/min of argon flow rate, 2,300° C of atomization temperature and 1.2–2.5 M of acids concentration were the best experimental conditions. The strong supression of the antimony signal by nickel, cobalt and copper was effectively eliminated with 1,10-phenanthroline. A detection limit of 1.2 ng was obtained with a precision of 4–5%. The reducing tube used in this technique is extremely simple and can be connected to all the types of graphite furnaces. Furthermore, this technique can be used for the determination of mercury [1].

Determination of B2 vitamers in serum of fish using high-performance liquid chromatography with fluorescence detection

A sensitive method is described for the determination of riboflavin (RF), flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) in serum of different fish using reversed-phase high-performance liquid chromatography (HPLC) with fluorimetric detection. Trichloroacetic acid was used to isolate B2 vitamers from the serum, and an aliquot of this solution was analysed by HPLC with a Zorbax-NH2 column with methanol-0.2 M phosphate buffer (1 + 9) as the mobile phase. The detection limits of RF, FMN and FAD in the serum were 4.89, 9.13 and 73.1 ng ml–1, respectively.

Determination of germanium by hydride generation with reducing tube followed by graphite furnace atomic absorption spectrometry using CH4/Ar as sweeper gas

ZusammenfassungBei dem beschriebenen Verfahren werden die Hydride in einem horizontalen Glasrohr erzeugt, das eine NaBH4-Perle enthält. Als optimale experimentelle Bedingungen ergaben sich: Spülgas (0,61/min) aus 10% CH4 und 90% Ar, Atomisierungstemperatur 2700° C, 2,5–3 M Säure. Die starke Beeinflussung des Ge-Signals durch Ni und Co wurde mit Hilfe von 1,10-Phenanthrolin eliminiert, die Störung durch Au mit Hilfe von Thiosemicarbazid. Das verwendete Reduktionsrohr ist sehr einfach und kann für alle Arten von Graphitöfen benutzt werden. Die Nachweisgrenze beträgt 2 ng, die Reproduzierbarkeit 3–4%.SummaryA sensitive method for the hydride generation and graphite tube furnace atomic absorption spectrometric measurements with a reducing tube using mixed gas (CH4 10% + Ar 90%) as sweeper gas has been developed for the determination of germanium. Germanium hydrides were generated in a horizontal glass tube, in which a pellet of NaBH4 was placed. 0.61/min of sweeper gas flow rate, 2,700° C of atomization temperature and 2.5–3 M of acidity range were the best experimental conditions. The strong supression of the germanium signal by Ni and Co was effectively eliminated with 1,10-phenanthroline and thiosemicarbazide was comparatively effective for Au. The reducing tube used in this technique is extremely simple and can be connected to all the types of graphite furnaces. A detection limit of 2 ng was obtained with a precision of 3–4%

Gas chromatographic determination of hydrogen sulphide in anoxic waters

Abstract A gas chromatographic method has been studied for the determination of hydrogen sulphide in anoxic waters. To suppress the escape and the oxidation of hydrogen sulphide in the water sample, either acetone or ethanol was mixed with the sample, and a small amount of hydroxylamine hydrochloride was added. The hydrogen sulphide in this solution was determined by gas chromatography. The proposed method is easy to perform and determination is possible for several days after the sampling. The limit of detection was about 0.1 ppm, the average of coefficients of detection was 9.2%.

A new method for separation and spectrophotometric determination of phosphate ion by the liquid-liquid extraction with benzophenone at an elevated temperature

ZusammenfassungBei dem beschriebenen Verfahren wird die mit Ammoniummolybdat in saurer Lösung gebildete gelbe Heteropolysäure bei 60° C in geschmolzenes Benzophenon extrahiert. Dieses wird durch Abkühlen verfestigt, in Methylpropionat gelöst und in dieser Lösung das Phosphat spektralphotometrisch als blaue Heteropolysäure bestimmt. Si, As und Ge, die ebenfalls mit Molybdat reagieren, werden durch die Extraktion abgetrennt.SummaryA new type of separation of phosphate ion, along with its spectrophotometric determination, was established by liquid-liquid extraction, where the yellow heteropoly acid formed by the reaction with ammonium molybdate in acid solution is quantitatively extracted into molten benzophenone at a temperature of about 60° C. When cooled down to room temperature, the benzophenone extract converts from the liquid state to the solid state. The resulting solidified extract is dissolved in methyl propionate, and the phosphate ion in the solvent is determined spectrophotometrically by the blue heteropoly acid method. Possible interference by Si, As and Ge is eliminated by the separation procedure.

Determination of B2 vitamers in the body fluid of plankton using high-performance liquid chromatography with fluorescence detection

A sensitive method, using high-performance liquid chromatography (HPLC) with fluorescence detection, has been developed for the separation and determination of B2 vitamers in the body fluid of plankton. B2 vitamers are liberated from the protein moiety in the body fluid by non-hydrolytic extraction with trichloroacetic acid and analysed by the proposed HPLC method. The major B2 vitamer in the body fluid of plankton is riboflavin, although there is also evidence to suggest the presence of endogenous enzymes that can decompose flavin mononucleotide and flavin adenine dinucleotide.