EXPRESS: A survey of the reactivity of in-vitro diagnostic bilirubin reagents developed in Japan using artificially prepared bilirubin materials: A comparison of synthetic delta, unconjugated, and taurine-conjugated bilirubin

Background: In-vitro diagnostic (IVD) bilirubin reagents based on oxidation with bilirubin oxidase (BOX) or vanadic acid (VA) for total and direct-reacting bilirubin (TB and DB) are widely used in Japan; however, their reactivity to unconjugated and conjugated bilirubin (UCB and CB) and delta bilirubin (DLB) has not been completely disclosed by manufacturers. We used artificially prepared bilirubin materials to investigate the reactivity with four IVD bilirubin reagents. Methods: Porcine UCB solution, chemically synthesized ditaurobilirubin (DTB) solution, and chemically synthesized DLB solution were used as surrogates of naturally occurring UCB, CB, and DLB, respectively. The TB and DB concentrations were measured by three BOX methods and one VA method, and the observed concentrations were compared with those obtained by the diazo-based reference measurement procedure (RMP). Results: The UCB and DLB concentrations were similar when any of the four IVD bilirubin reagents were used during TB measurement. This was consistent with RMP and exhibited a converged inter-method variation. Compared with RMP, significantly low DTB concentrations were observed by the IVD bilirubin reagents despite the converged inter-method variation. In DB measurement, some reagents reacted doubtfully with UCB, while showed lower DTB concentrations than its corresponding TB concentration. Reactivity with DLB was different for each method including RMP. Some reagents were developed to react less with DLB and others to strongly react with DLB. Conclusions: We revealed the reactivity of IVD-TB and IVD-DB reagents to artificially prepared bilirubin materials, and their consistency with RMP. The DB data results vary depending on the reagents used.

HYDROGEN GAS SENSOR BASED ON POLYPYRROL MODIFIED BY DAWSON TYPE HETEROPOLIANION

В статье рассмотрена возможность модифицирования полипиррола анионным комплексом вольфрамовой гетерополикислоты типа Доусона, имеющей химическую формулу H[PWO], и дальнейшего использования модифицированного полипиррола для создания на его основе сенсора на газообразный водород. Фосфорновольфрамовая кислота типа Доусона была синтезирована по методу Дрекселя и выделена эфиратной экстракцией. Анализ свойств гетерополикислоты и модифицированного гетерополикислотой полипиррола был осуществлен методами амперометрии и РФС, а также фотохимически. Модифицирование полипиррола гетерополианионом 2-18 ряда было проведено электрохимическим методом. Была оценена возможность использования такого газового сенсора для анализа газообразного водорода в большом интервале концентраций (от десятых единиц ppm, до объемных процентов). Было также частично определено влияние таких климатических факторов, как влажность и температура, и была оценена перекрестная чувствительность на ряд не измеряемых компонентов. This article discusses material on electrochemistry and the application of polypyrrole, which belongs to the class of «conductive polymers». The possibility of its modification by the anionic complex of a phospho tungsto-vanadic acid of the Dawson type, with the chemical formula H[PWO], and further use of the modified polypyrrole to create a hydrogen gas sensor based on it, is considered. Phospho tungsto-vanadic heteropoly acid of the Dawson type was synthesized with the known method [1, p. 180-181], and isolated by ether extraction. The analysis of properties, heteropoly acid content, and polypyrrole modified with a heteropoly acid was carried out by amperometry and XPS methods, as well as photochemically. Modification of polypyrrole heteropolyanion of 2-18 type was carried out by the electrochemical method. The presence of the heteropoly anion in the structure of the heteropoly acid-modified polypyrrole film during the repeated washing with water indicates the formation of a chemical bond between the anion of the heteropoly acid and the chain of the conductive polymer, which was also indirectly confirmed by amperometry and element analysis, as well as a positive test result of testing the sensitivity of the gas cell to hydrogen made on the basis of obtained modified polypyrrole. The possibility of using such the gas sensor to measure hydrogen in a wide range of concentrations (from tenths of ppm to volume percent) was evaluated. The influence of ambient factors such as humidity and temperature was also partially determined, and cross sensitivity to a number of unmeasured components was evaluated.

Reactivity of bilirubin photoisomers on the measurement of direct bilirubin using vanadic acid method

Objective Investigation of the reactivity of fractions of bilirubin photoisomers with the vanadic acid oxidation method. Methods Bilirubin photoisomers were prepared by irradiating a bilirubin/human serum albumin solution with blue light emitting diode. Direct bilirubin and bilirubin fractions were measured using the vanadic acid oxidation method and high-performance liquid chromatography in the sample before and after irradiation. Results Direct bilirubin was increased in the solution containing bilirubin photoisomers. ( EE)-/( EZ) -cyclobilirubin-IXα and ( ZE)-/( EZ)-bilirubin-IXα completely disappeared after the addition of vanadic acid. Conclusion Bilirubin photoisomers reacted as direct bilirubin in the vanadic acid oxidation method.

Vanadium oxide-based photochromic composite film

V2O5-based composite films were fabricated using peroxo-iso-poly vanadic acid as the filler and transparent urethane resin as the matrix, and the resulting composite films exhibited photochromic property when irradiated with ultraviolet (UV) light.