2–15 g of mercury has been determined by exchange with zinc in65Zn labelled zinc sulphide. The influence of various ions which are likely to interfere in the determination of mercury has also been studied.
Specific surface area of antimony oxide samples, one commercial and the other prepared from antimony trichloride have been measured by heterogeneous isotope exchange, gas adsorption, airpermeability and microscopic methods. Specific surface areas obtained by these four methods for the two samples were compared and the observed differences are explained.
Authors:B. Rangamannar, B. Acharya, J. Sankaraiah, and K. Varma
The possibility of determination of 10–80 g of manganese by radiochemical displacement of zinc from a labelled zinc-PAN complex has been demonstrated. pH 6 borate buffer was suitable for quantitative displacement. The effect of diverse ions on the displacement reaction is also reported.
Authors:Pankajkumar B. Nariya, Vinay J. Shukla, Rabinarayan Acharya, and Mukeshkumar B. Nariya
The aim of this study was to isolate and identify three biologically active flavonoids, quercetin, kaempferol, and apigenin, from the hydrolyzed methanolic extract of three indigenous medicinal Cordia species, i.e., Cordia macleodii, Cordia dichotoma, and Cordia rothi barks using preparative thin-layer chromatography (TLC) and high-performance (HP)TLC methods. The isolation of flavonoid fraction was accomplished by preparative TLC method using reference standard. For achieving good separation, a mobile phase of toluene–ethyl acetate–GAA–formic acid (5:5:0.5:1) was used. The ultraviolet (UV)-based densitometry determination was carried out at 254 nm in reflection—absorption mode. The antioxidant compounds in the samples were screened through 2,2-diphenyl-1-picrylhydrazyl (DPPH) derivatization method. The method was partially validated in terms of linearity, specificity, and sensitivity. All three standards showed good linearity in the range of 2500–7500 ng with respect to area. Limit of detection (LOD) and limit of quantitation (LOQ) for quercetin were 9.4 and 28 ng; for apigenin, 30 and 92 ng; and for kaempferol, 57 and 173 ng. From the analysis, quercetin (0.21%) and kaempferol (0.19%) in C. rothi and apigenin (0.28%) in C. dichotoma were found to be the highest. The isolation and identification of these flavonoids have not yet been found in the literature and they are reported in this study for first time. From this, it is concluded that planar chromatography has a potential as a rapid and simple tool for the identification and quantification of phytochemicals in complex mixtures and marker-based samples.
Authors:R.N. Acharya, K. Sudarshan, A.G.C. Nair, Y.M. Scindia, A. Goswami, A.V.R. Reddy, and S.B. Manohar
The guided thermal neutron beam at 100 MW Dhruva research reactor facility of Bhabha Atomic Research Centre (BARC) was used to carry out prompt gamma-ray neutron activation analysis (PGNAA). The prompt k0-factors have been determined for the isotopes of the elements H, B, K, Co, Cu, Ca, Ti, Cr, Cd, Ba, Hg and Gd with respect to 1951 keV gamma-line of 36Cl. The prompt k0-factors for H, Cl and Cu were also measured with respect to the 1381 keV gamma-line of 49Ti. Different samples like NH4Cl, Ti metal, cobalt chloride and other stoichiometric compounds and pure metals were used for this purpose. Prompt gamma-rays were accumulated using a 22% HPGe detector connected to a PC based 8k MCA in single mode counting. The energy calibration in the range of 100–8500 keV was carried out using gamma-rays from 152Eu and 60Co, and the prompt gamma-rays from 36Cl whereas the absolute detection efficiency for this energy range was determined using 152Eu and prompt gamma-rays from 36Cl and 49Ti.