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- Author or Editor: Nilima Rajurkar x
- Chemistry and Chemical Engineering x
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Abstract
The effect of a medium dose of gamma radiation on antioxidant activity of Amoora rohitaka was studied. Radiation doses were 0, 1, 3 and 5 kGy. Antioxidant activity was screened by using different assay. With increasing dose the formation of Maillard reaction products (MRPs) contributes to the increase in the antioxidant activity. MRPs are formed as a result of Maillard reaction. In ABTS [2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid di-ammonium salt] assay, ethanol extract showed increase in scavenging activity. It also showed a marked increase in polyphenolic contents. The present study reveals that gamma irradiation can be an efficient process to increase antioxidant activity of Amoora rohitaka.
Abstract
The effect of some alkali metal chlorides on obstruction effect /
/ and activation energy /E/ for the tracer-diffusion of cobalt ions is studied in agar gel medium using the zone-diffusion technique. It is observed that both the parameters, and E, decrease with increasing charge density of cation of the supporting electrolyte. This trend is explained on the basis of competitive hydration between ions and agar molecules and the relative distortion in the water structure brought about by these different ions and agar molecules, respectively.
Abstract
A nondestructive instrumental neutron activation analysis technique is applied for the analysis of precious ancient punchmark coins. Coins ranging between 8th century B.C. to 2nd century B.C. were irradiated with thermal neutrons in a252Cf neutron source facility and analyzed by comparator method of instrumental neutron activation analysis, using high purity germanium detector coupled to a multichannel analyzer, the activities being measured at photopeak energies of the corresponding radioisotopes. It is observed that punchmark coins are mainly of two types: copper or silver based. Other elements present in varying proportions are gold, arsenic and antimony.
Abstract
Tracer-diffusion of Co2+ ions is studied in agar gel in the presence of sodium and potassium nitrates at 25°C. The diffusion coefficient values at various electrolyte concentrations are compared with the corresponding theoretical values computed on the basis of Onsager's theory. The deviations from the theory are attributed to the various co-occurring effects in the diffusion medium. The activation energy for the process of diffusion of Co2+ ions in presence of above electrolytes is also reported.
Abstract
The concentration dependence of experimental diffusion coefficients of cobalt ions in presence of some alkali metal chlorides is examined in the light of the Onsager theory. The diffusion coefficients are measured in 1% agar gel using the zone-diffusion technique. The positive and negative deviations observed at higher and lower concentrations, respectively, are explained in terms of relative contributions of various types of effects occurring in the diffusion medium.
20-Hydroxyecdysone (20E), an imperative phytoecdysteroid, regulates several biochemical and physiological processes during the different developmental stages in insects. The aim of the present work was to validate an analytical method for the detection and identification of the 20E content in Sesuvium portulacastrum using high-performance thin-layer chromatography (HPTLC) combined with image analysis and using high-resolution mass spectrometry (HRMS). Using HPTLC, the better separation of 20E was achieved on TLC plate prewashed with ethanol—ethyl acetate—water (8:2:0.5) and using the solvent system consisting of chloroform—methanol—benzene (12.5:2.5:1.5) at R F value of 0.30. The bands were documented using a TLC visualizer and scanned at 254 nm in absorption mode. The method was validated for specificity, linearity, precision, robustness, stability, accuracy, limit of detection (LOD), and limit of quantification (LOQ) as per the International Conference on Harmonization (ICH) guidelines. The linear calibration curve was achieved in the range of 50–500 ng band−1 with the most significant correlation coefficient (r = 0.997). The relative standard deviations for intra-day and inter-day precisions were found to be 1.897 and 3.125 at 300 ng band−1, and the limit of detection and limit of quantification were 4.67 and 14.16 ng band−1, respectively. Furthermore, 20-hydroxyecdysone isolated from standard and plant sample bands was identified using indirect TLC—HRMS analysis. The HPTLC method and the indirect TLC—HRMS analysis were observed to be simple, precise, accurate, and suitable for the determination of 20E in S. portulacastrum. In the phytopharmaceutical industry, the present method can be applied for the screening and routine quality control of 20E in plant materials and formulations.
