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Showing papers by "Purnendu K. Dasgupta published in 1993"


Journal ArticleDOI
01 Jan 1993-Talanta
TL;DR: High performance, fully referenced, computer interfaced detectors are described that are pulsed at high speeds to attain measurement standard deviations in the range of 2-3 x 10(-6) absorbance.

104 citations


Journal ArticleDOI
TL;DR: In this paper, a tubular cation-exchange membrane is installed at the end of a 60 cm-long 75 µm-bore fused-silica capillary, and a static dilute acid regenerant solution surrounds the membranes that functions as a suppressor.
Abstract: A tubular cation-exchange membrane is installed at the end of a 60-cm-long 75-[mu]m-bore fused-silica capillary. A static dilute acid regenerant solution surrounds the membranes that functions as a suppressor. With positive high voltage applied to the capillary inlet and the regenerant solution grounded, effective suppression of electrolytes such as solutions of alkalic metal borate, glycinate, or cyanide is observed. Electroosmotic flow carries the capillary effluent past the suppressor into a conductivity detection cell constituted by two platinum wires inserted through the wall of a poly(vinyl chloride) capillary. The system provides detection limits in the 10--20 [mu]g/L range for a variety of anions; a typical separation requires 15 min. Applicability to a variety of real samples is demonstrated. 26 refs., 10 figs.

100 citations


Journal ArticleDOI
TL;DR: In this article, the authors describe the design and construction of high-efficiency netted denuders of annular and parallel plate geometries, which are porous and are wettable with a very small flow of water.
Abstract: Design and construction of high-efficiency netted denuders of annular and parallel plate geometries are described. The silica-coated glass surfaces of these denuders are porous and are wettable with a very small flow of water. The parallel plate design is simpler in construction and offers better collection efficiency and loner particle losses than the annular design. Particle losses are, however, very low for both designs, ≤0.5% at the intended sampling rates. Collection efficiency for SO 2 for two parallel plates (50×100 mm active area) separated by 3 mm is essentially quantitative at 10 L/min. Coupled to an ion chromatograph, the detection limit for SO 2 for such a system is 500 parts per quadrillion for a 8-min sample

99 citations


Journal ArticleDOI
TL;DR: In this paper, the maximum permissible sample throughput is a function of the electric field strength, capillary length and injection volume, and the relation between the various parameters is theoretically and experimentally discussed.

54 citations



Journal ArticleDOI
01 Sep 1993-Talanta
TL;DR: Using circuitry based on newly available switched integrator integrated circuit (IC) packages, it is possible to construct inexpensive absorbance detectors with p-p noise levels as low as 3 microAU under actual use conditions.

35 citations


Journal ArticleDOI
TL;DR: In this paper, a novel approach to simultaneously practicing both suppressed and nonsuppressed ion chromatography (IC) is proposed, where a constant concentration of NaOH is introduced by an in-line microelectrodialytic NaOH generator, and this is followed by a second conductivity detector.
Abstract: A novel approach to simultaneously practicing both suppressed and nonsuppressed ion chromatography (IC) is proposed. Following the detector of a conventional NaOH eluent suppressed IC system, a constant concentration of NaOH is introduced by an in-line microelectrodialytic NaOH generator, and this is followed by a second conductivity detector. The second detector background is typically maintained at a level of 20-30 [mu]m/cm (corresponding approximately to 0.1 mM NaOH), and the detector output is the same as what would be observed in a single column mode with a low concentration NaOH eluent. Together, the two detector outputs provide detectabilities at the microgram per liter level across the pK[sub a] range-from fully dissociated to very weak acids (up to pK[sub a] 9.5). Excellent linearity of response is observed, and the system provides qualitative information about peak purity and eluite pK[sub a]. In addition to the usual ratio plots, it is suggested that multidimensional detection in any separation system is best served by plotting the raw detector outputs against each other. 16 refs., 11 figs.

34 citations


Journal ArticleDOI
TL;DR: In this article, the authors show that up to a threefold increase in sensitivity without loss of separation efficiency can be achieved by connecting a larger diameter capillary at the measurement point.

26 citations


Journal ArticleDOI
01 Jun 1993-Talanta
TL;DR: The experimental system involves the permeative preconcentration of CO(2) from an acidified sample through a tubular silicone rubber membrane into a suitable receptor and the conductometric measurement method using a solution of 1-10mM tris(hydroxymethylamino)methane as receptor is recommended.

26 citations


Journal ArticleDOI
01 Mar 1993-Talanta
TL;DR: The sandwich cell described by Pavon et al. and a similar sandwich cell, except with angled (45 degrees, confocal) single strand optical fibers and a conventional Z-type cell of 6-mm path length, show less susceptibility to artifact absorbance signals from RI changes than the Z-cell.

12 citations


Journal ArticleDOI
01 Jul 1993-Talanta
TL;DR: The technique is based on the oxidative condensation reaction between 1-anilinonaphthalene-8-sulfonic acid and 4-aminoantipyrine in the presence of H(2)O(2), and Hematin is a good peroxidatic catalyst for this reaction; its effectiveness is significantly enhanced in an ammoniacal medium.

Journal ArticleDOI
TL;DR: In this paper, a 2-electrode cell was devised in which the trapped eluite was subjected to electromigration using a third electrode and a high electric field, and it was suggested that this design may be significant utility for future experiments, including tandem ion chromatography-capillary electrophoresis.