Showing papers by "Purnendu K. Dasgupta published in 2013"
TL;DR: The method was validated against a microdiffusion approach and applied to the measurement of cyanide in rabbit and human blood, and permits field measurement of blood cyanides in <4 min.
43 citations
TL;DR: This work describes an approach to prepare an open tubular ion exchange (OTIE) column by coating a monolayer of anion exchange nanoparticle to a 16-20 μm bore polymethylmethacrylate (PMMA) capillary, and demonstrates the possibility of pKa-differentiated ion exchange capacity measurements.
Abstract: We describe an approach to prepare an open tubular ion exchange (OTIE) column by coating a monolayer of anion exchange nanoparticle to a 16–20 μm bore polymethylmethacrylate (PMMA) capillary. The latex nanoparticle was electrostatically attached to carboxylate groups on the inner wall of capillary, pretreated with strong base for hydrolyzing the ester. Several approaches to nondestructively measure ion exchange capacities (IEC) of the columns were examined: (a) adsorption–desorption of an intensely fluorescent ion, e.g. fluorescein, and off-line fluorometry, (b) loading a weakly retained ion (e.g., IO3–), frontal displacement by a strongly bound ion (e.g., Cl–), and online optical or conductometric boundary detection, and (c) similar to the above except displacement being accompanied by reaction (e.g., acid–base titration). To our knowledge, this is the first time on-column titration has been used to measure capacities. By using different pH displacer solutions, we demonstrate for the first time the possi...
19 citations
TL;DR: It is shown that the simple repetition of an equilibration process at each plate (a spreadsheet row) followed by discrete movement of the mobile phase down by a row, easily automated by a subroutine (a "Macro" in Excel), readily simulates chromatography.
16 citations
TL;DR: The data reported here indicate that lactating women may be exposed to perchlorate through dietary sources at markedly higher levels than estimated previously, including those used to develop drinking water standards.
11 citations
TL;DR: The highly characteristic anion profile and in particular the absence of tartrate can readily be used to identify authentic açaı́ products and the present analytical approach for phytate may be superior to extant methods.
Abstract: Many products labeled acai are presently marketed as natural supplements with various claimed health benefits. Authentic acai is expensive; as a result, numerous products labeled as containing acai are being sold that actually contain little or no acai. Authentic acai samples from Brazil and Florida as well as several reputed acai products were analyzed by suppressed conductometric anion chromatography. Columns with different selectivities were used to obtain a complete separation of all anions. Tandem mass spectrometry was used for confirmation of the less common ions. Quinate, lactate, acetate, formate, galacturonate, chloride, sulfate, malate, oxalate, phosphate, citrate, isocitrate, and myo-inositol hexakisphosphate (phytate) were found. Only the Florida acai had detectable levels of hexanoate. No acai sample had any detectable levels of tartrate, which is present in abundance in grape juice, the most common adulterant. The highly characteristic anion profile and in particular the absence of t...
6 citations
TL;DR: In this paper, the extent of soil arsenic contamination in agricultural plots in the Bengal Delta through contaminated groundwater irrigation was investigated, and the analysis for estimation of soil OOC was performed by one-way ANOVA to determine significant differences between groups at P<0.05.
Abstract: The study investigated the extent of soil arsenic (As) contamination in agricultural plots in Bengal Delta through contaminated groundwater irrigation. Edaphic levels of As and oxidizable organic carbon (OOC) were tested along a depth gradient (0 to 160 ft) in agricultural plots. Soil samples were collected from surface up to 160 feet depth at every 5 feet. By boreholes drilling and soil arsenic was estimated in ICP-MS. The analysis for estimation of soil OOC was performed. Statistical analyses were performed by one-way ANOVA to determine significant differences between groups at P<0.05. Concentration of As in soil was observed to be highest in surface soil, then decreased with increasing depth till about 40 ft, after which the concentration remained constant. Similar trends were noted for OOC. OOC showed significant (P < 0.05) positive correlations with the As levels. Natural organic matter may enhance the release of As from soils and sediments into the soil solution, and thus can help in As leaching into the groundwater. Detailed investigation of the soil profile and the extent of bioaccumulation in the edible crops are urgently needed in those arsenic-contaminated areas.
2 citations