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
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TL;DR: A balanced demodulator integrated circuit chip was used to fabricate a dual wavelength-frequency-selective LED-based absorbance detector, which successfully compensated refractive index (RI) effect and turbidity effect in test flow systems.
21 citations
21 citations
TL;DR: The method was successfully applied to accurately determine sub-μg L(-1) level Hg in standard reference water samples, and an overall 50-fold improvement in the limit of detection was observed relative to direct measurement by CVAAS.
21 citations
20 citations
TL;DR: In this paper, a helical, filament-filled perfluorosulfonate membrane suppressor is utilized with high concentrations (0.1-1.0 M) of NaCl (sometimes including {le} 1 mM NaOH) as regenerant to convert H{sup +} in the eluent (up to 10 mM HNO{sub 3}) to Na{sup+}.
Abstract: A helical, filament-filled perfluorosulfonate membrane suppressor is utilized with high concentrations (0.1-1.0 M) of NaCl (sometimes additionally including {le} 1 mM NaOH) as regenerant to convert H{sup +} in the eluent (up to 10 mM HNO{sub 3}) to Na{sup +}. Elution of the weak acid analytes from the suppressor as their Na salts causes an increase in pH, monitored optically by the postsuppressor introduction of an acid-base indicator. Theoretical considerations involve the concentration and K{sub In} of the indicator and their effects on the background absorbance, dynamic range, and analyte response. Results are presented for 4-nitrophenol as indicator (base form monitored at 400 nm) introduced permeatively through a membrane reactor. Analyte acids (pK{sub A} range {approx} 4.5-9.5) are selectively detected; maximum sensitivity is reached in the middle of this pK{sub A} range. The sensitivity for high pK{sub A} acids is poor, caused by a substochiometric suppressor reaction. Detectability for the moderate pK{sub A} acids is in the low micromolar (50 pmol) level, even with a pH 2 eluent. Capability of gradient elution and advantages of a pH 2 eluent are demonstrated. Operational considerations of the membrane suppressor, e.g., adjustment of the suppressor effluent pH by addition of NaOH to themore » regenerant and relative flow directionality, transmembrane loss of very weak acids in the uncharged form, etc., are discussed in terms of the results.« less
20 citations
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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