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A microcountercurrent flame photometric detector [micro]cc-FPD) was adapted and optimized for ultrafast gas chromatographic (GC) separation and detection of organophosphor (OP) and organosulfur (OS) compounds on short chromatographic columns. Air and hydrogen are introduced to the [micro]cc-FPD from opposite directions, creating a hydrogen-rich flame. In this [micro]cc-FPD, combustion takes place between the burner tips without touching them. The separation between the tips and the flame reduces heat loss from the flame to the surrounding environment, resulting in low hydrogen consumption and a compact flame. The [micro]cc-FPD is capable of detecting very narrow (13 ms) chromatographic peaks. An ultrafast GC separation of a group of six OP and OS compounds is achieved within less than 5 s using fast temperature programming of a 0.5-m-long microbore column. Very fast separations are also demonstrated on a 1-m-long microfabricated column consisting of 150-[micro]m-wide, 240-[micro]m-deep channels, etched in a 1.9-cm square silicon chip, covered with a Pyrex wafer, and statically coated with dimethyl polysiloxane. With a hydrogen flow rate of 10 mL/min, the detection limit for OP is 12 pg of P/s and 3 ng of S/s for OS compounds at a signal-to-noise ratio of 2. The coupling of a microfabricated column and a miniature FPD is an important step toward the development of a miniaturized GC-FPD capable of ultrafast detection of low levels of OP and OS compounds.

Abstract -- The main analytical characteristics of the reaction of hexaoxacycloazochrom with lead were determined. A method for the sorption preconcentration of lead on the Thiopan 14 sorbent was proposed. [...]

Abstract -- Complexes of scandium(III) with 2,2',3,4-tetrahydroxy-3'-sulfo-5'-nitroazobenzene were studied in the absence and presence of a third component, papaverine, dibazole, or urotropine. Optimal conditions for their formation were found, and [...]

Abstract -- Optical and colorimetric characteristics of 1-nitroso-2-naphthol-3,6-disulfonic acid (nitroso-R-salt) are studied in aqueous solutions at pH 4-10. Equations of calibration plots are obtained as the colorimetric functions of the [...]

Abstract -- A procedure for the photometric determination of mercaptan sulfur in light petroleum products was developed. This procedure is based on the formation of colored analytical species in an [...]

Byline: I. E. Kalinichenko (1), L. N. Demutskaya (1) Abstract: A method was proposed for determining nitrates in drinking water from the results of absorbance measurements at three wavelengths in the ultraviolet region of the absorption the nitrate ion. The determination limit depends on the water type and varies from 0.05 to 0.5 mg/L. A relatively simple equation was proposed for calculating nitrate concentrations. Author Affiliation: (1) Dumanskii Institute of Colloid and Water Chemistry, National Academy of Sciences of Ukraine, ul. Vernadskogo 42, Kiev, 03680, Ukraine Article History: Registration Date: 06/10/2004

Byline: Kh. A. Mirzaeva (1), M. S. Akhmedova (1), A. Sh. Ramazanov (1), S. A. Akhmedov (1) Abstract: The interactions of Dimedrol (Benadryl) and papaverine with Sulfonazo were studied by extraction--photometry. The formation of sparingly soluble associates that are readily extractable with butanol was found, and conditions for the formation and extraction of these associates were optimized. The composition and solvation numbers were found, and the mechanism of formation and the structure of the above ion associates were discussed. The kinetics of extraction was studied, and the recovery (96.5--97.5%) and distribution ratios (15.4 +- 0.5 and 13.8 +- 0.3 for Dimedrol and papaverine, respectively) were calculated. Procedures for the extraction--photometric determination of Dimedrol and papaverine were developed and applied to the analysis of pharmaceutical dosage forms. These procedures are characterized by adequate sensitivity, rapidity, and selectivity. Author Affiliation: (1) Department of Chemistry, Dagestan State University, ul. M. Gadzhieva 43a, Makhachkala, 367025, Russia Article History: Registration Date: 06/10/2004

Byline: V. P. Vasil'ev (1), A. V. Katrovtseva (1), A. I. Lytkin (1), N. V. Chernyavskaya (1) Abstract: The complexation of zirconium(IV) with Semimethylthymol Blue ([H.sub.4]L) was studied by spectrophotometry. The formation of the (ZrOH).sub.2([H.sub.2]L).sup.2+ .sub.2 complex with log[beta] = 20.68 +- 0.12 and [epsilon].sub.565 = (7.26 +- 0.02) x 10.sup.4 was revealed by the isomolar series and molar ratio methods. A simple, reliable, and sensitive method was developed for the photometric determination of zirconium. The calibration plot is linear in the concentration range of 10.sup.--6--10.sup.--5 M zirconium. In a sample of frit 24--70 containing 5.7% ZrO.sub.2, 5.44 +- 0.15% ZrO.sub.2 was found. Author Affiliation: (1) Ivanovo State University of Chemical Technology, pr. F. Engel'sa 7, Ivanovo, 153460, Russia Article History: Registration Date: 06/10/2004

Byline: Mir F. Mousavi (1), A. Rahmani (2), M. Barzegar (1), A. Jabbari (2) Abstract: A simple and sensitive catalytic-photometric method for the determination of trace amounts of palladium(II) based on its heterogeneous catalytic effect on the reduction of neutral red (NR) by hypophosphite (HP) has been developed. The reaction was monitored at 530 nm and the time elapsed (At) for the absorbance to decrease from its initial value by 1.5 absorbance units was recorded using the variable time method. The influence of reaction variables is discussed. The ranges of linearity were 0.108--6.533 ppm and 0.032--0.653 ppm palladium(II) at temperatures of 30 and 55degC, respectively. The relative standard deviations of the developed method were 2.5 and 2.7% (for 8 replicate determinations of 1.110 ppm Pd(II)) at 30 and 55degC, respectively. The effect of interferences from other metal ions and some anions was studied. The developed method has been successfully tested for determination of Pd(II) in Al--Si--Pd catalysts. Author Affiliation: (1) Department of Chemistry, Tarbiat Modarres University, P. O. Box: 14115-111, Tehran, Islamic Republic of Iran (2) Department of Chemistry, Hormozgan University, Bandar Abbas, Islamic Republic of Iran Article History: Registration Date: 06/10/2004

On-line coupling of reversed-phase microcolumn liquid chromatography (micro-RPLC) and sulfur-selective flame photometric detection (S-FPD) was studied for the selective and direct determination of thiodiglycol, bis(2-hydroxyethylthio)methane, 1,2-bis(2-hydroxyethylthio)ethane, 1,3-bis(2-hydroxyethylthio)propane, and 1,4-bis(2hydroxyethylthio)butane, which are breakdown products of the chemical warfare agents called sulfur mustards. Both isocratic and gradient elution were used. To improve sensitivity, large-volume injections were applied together with peak compression by displacement for late-during analytes. With S-FPD, detection limits of 1 (mu)g/mL were obtained for all compounds. Using the same approach, the target analytes as well as various oxidation products could be identified by micro-RPLC with electrospray ionization mass spectrometry (ESI-MS) and ESI-MS/MS. The optimized micro-RPLC-S-FPD system was successfully used for the analysis of a spiked soil sample.

Abstract -- A procedure was developed for the flow-injection photometric determination of mercaptans in light oil products. The use of sodium nitroferricyanide as the photometric reagent at 540 nm provides [...]