Author
Purnendu K. Dasgupta
Other affiliations: Dow Chemical Company, Texas Tech University, University of California, Davis ...read more
Bio: Purnendu K. Dasgupta is an academic researcher from University of Texas at Arlington. The author has contributed to research in topics: Ion chromatography & Detection limit. The author has an hindex of 62, co-authored 506 publications receiving 16779 citations. Previous affiliations of Purnendu K. Dasgupta include Dow Chemical Company & Texas Tech University.
Papers published on a yearly basis
Papers
More filters
TL;DR: In this article, the authors discuss the automated diffusion-based collection and measurement of atmospheric trace gases using liquid core waveguide (LCW) based diffusion scrubber (DS) devices, which provide a contained liquid volume and can be operated in a stopped liquid flow mode.
Abstract: Publisher Summary This chapter discusses the automated diffusion-based collection and measurement of atmospheric trace gases. Diffusion based collection of trace gases into a liquid not only offers a means of discrimination from concurrently present particles, the integration of continuous or batch mode analytical systems for the analysis of the liquid effluent provides unprecedented sensitivity and accuracy. Based on these principles, many gases can be routinely measured at low to sub-ppb levels. Diffusion scrubber (DS) devices provide a contained liquid volume and can be operated in a stopped liquid flow mode where they can themselves provide further preconcentration. liquid core waveguide (LCW) based DS devices constitute a unique new entry and may offer very inexpensive alternatives for measuring gases at typical urban levels. Selective luminogenic reactions for gas measurement using LCW DS devices have not been reported and may be uniquely attractive and sensitive.
12 citations
TL;DR: A width-based quantitation (WBQ) paradigm complementing height or area based approaches can offer superior overall performance compared to area- or height-based linear regression methods, rivaling weighted linear regression, provided that response is uniform near the height used for width measurement.
Abstract: Height- and area-based quantitation reduce two-dimensional data to a single value. For a calibration set, there is a single height- or area-based quantitation equation. High-speed high-resolution data acquisition now permits rapid measurement of the width of a peak (Wh), at any height h (a fixed height, not a fixed fraction of the peak maximum) leading to any number of calibration curves. We propose a width-based quantitation (WBQ) paradigm complementing height or area based approaches. When the analyte response across the measurement range is not strictly linear, WBQ can offer superior overall performance (lower root-mean-square relative error over the entire range) compared to area- or height-based linear regression methods, rivaling weighted linear regression, provided that response is uniform near the height used for width measurement. To express concentration as an explicit function of width, chromatographic peaks are modeled as two different independent generalized Gaussian distribution functions, r...
12 citations
TL;DR: Thin film perfluorosulfonate ionomer sensors overcoated with cellulose triacetate, polyvinyl alcohol (PVA)-H 3 -PO 4 , or PVA-PFSI-H 3 PO 4 composite films operated in a pulsed voltammetric mode are described.
Abstract: Thin film perfluorosulfonate ionomer (PFSI) sensors overcoated with cellulose triacetate, polyvinyl alcohol (PVA)-H 3 -PO 4 , or PVA-PFSI-H 3 PO 4 composite films operated in a pulsed voltammetric mode are described
11 citations
TL;DR: The effect of several critical parameters, such as the composition of the liquid film and the MEKC running electrolyte, sampling period and film evaporation on the collection efficiency, separation efficiency and calibration behaviour are described.
11 citations
Patent•
04 Sep 2001
TL;DR: In this paper, the authors proposed a two-dimensional conductometric detection in simultaneous suppressed and nonsuppressed ion chromatography with post-column reactions in which band spreading at detrimental levels is effectively controlled.
Abstract: Packings or equivalent structures which produce radial mixing in channels can be used to enhance reagent addition devices for ion chromatography post column reactions in which band spreading at detrimental levels is effectively controlled. Application to two dimensional conductometric detection in simultaneous suppressed and nonsuppressed ion chromatography.
11 citations
Cited by
More filters
TL;DR: The manipulation of fluids in channels with dimensions of tens of micrometres — microfluidics — has emerged as a distinct new field that has the potential to influence subject areas from chemical synthesis and biological analysis to optics and information technology.
Abstract: The manipulation of fluids in channels with dimensions of tens of micrometres--microfluidics--has emerged as a distinct new field. Microfluidics has the potential to influence subject areas from chemical synthesis and biological analysis to optics and information technology. But the field is still at an early stage of development. Even as the basic science and technological demonstrations develop, other problems must be addressed: choosing and focusing on initial applications, and developing strategies to complete the cycle of development, including commercialization. The solutions to these problems will require imagination and ingenuity.
8,260 citations
TL;DR: It is reported that magnetite nanoparticles in fact possess an intrinsic enzyme mimetic activity similar to that found in natural peroxidases, which are widely used to oxidize organic substrates in the treatment of wastewater or as detection tools.
Abstract: Nanoparticles containing magnetic materials, such as magnetite (Fe3O4), are particularly useful for imaging and separation techniques. As these nanoparticles are generally considered to be biologically and chemically inert, they are typically coated with metal catalysts, antibodies or enzymes to increase their functionality as separation agents. Here, we report that magnetite nanoparticles in fact possess an intrinsic enzyme mimetic activity similar to that found in natural peroxidases, which are widely used to oxidize organic substrates in the treatment of wastewater or as detection tools. Based on this finding, we have developed a novel immunoassay in which antibody-modified magnetite nanoparticles provide three functions: capture, separation and detection. The stability, ease of production and versatility of these nanoparticles makes them a powerful tool for a wide range of potential applications in medicine, biotechnology and environmental chemistry.
4,500 citations
TL;DR: The ability of DLLME technique in the extraction of other organic compounds such as organochlorine pesticides, organophosphorus pesticides and substituted benzene compounds were studied.
2,959 citations
TL;DR: It is concluded that when nonmonotonic dose-response curves occur, the effects of low doses cannot be predicted by the effects observed at high doses, and fundamental changes in chemical testing and safety determination are needed to protect human health.
Abstract: For decades, studies of endocrine-disrupting chemicals (EDCs) have challenged traditional concepts in toxicology, in particular the dogma of “the dose makes the poison,” because EDCs can have effects at low doses that are not predicted by effects at higher doses. Here, we review two major concepts in EDC studies: low dose and nonmonotonicity. Low-dose effects were defined by the National Toxicology Program as those that occur in the range of human exposures or effects observed at doses below those used for traditional toxicological studies. We review the mechanistic data for low-dose effects and use a weight-of-evidence approach to analyze five examples from the EDC literature. Additionally, we explore nonmonotonic dose-response curves, defined as a nonlinear relationship between dose and effect where the slope of the curve changes sign somewhere within the range of doses examined. We provide a detailed discussion of the mechanisms responsible for generating these phenomena, plus hundreds of examples from...
2,475 citations
Brigham and Women's Hospital1, Boston University2, University of California, Los Angeles3, Boston Children's Hospital4, University of Alabama at Birmingham5, Stanford University6, Northwestern University7, Aalborg University8, Cardiff University9, University of Pennsylvania10, Erasmus University Rotterdam11, Medical University of South Carolina12
TL;DR: The revised guidelines for the management of thyroid disease in pregnancy include recommendations regarding the interpretation of thyroid function tests in pregnancy, iodine nutrition, thyroid autoantibodies and pregnancy complications, thyroid considerations in infertile women, hypothyroidism in pregnancy and thyrotoxicosis in pregnancy.
Abstract: Background: Thyroid disease in pregnancy is a common clinical problem. Since the guidelines for the management of these disorders by the American Thyroid Association (ATA) were first published in 2...
2,409 citations