Copper-modified carbon nano-onions as electrode modifiers for the electroanalysis of the antiretroviral drug Efavirenz

The high prescription and consumption rate of antiretroviral drugs (ARV) such as Efavirenz (EFV) in South Africa for the treatment of the human immunodeficiency virus (HIV) has resulted in its presence in wastewater and surface water. Herein we report the electroanalysis of EFV at oxidised boron-nitrogen doped carbon nano-onions (oxi-BNCNO) and microscale branched copper cluster (CuC) modified glassy carbon electrodes. Potentiostatic electrodeposition of CuC on the oxi-BNCNO/GCE platform resulted in a stable and electrocatalytic surface that accelerated electron transfer between the analyte and the CuC/oxi-BNCNO/GCE surface, making quantification efficient. The electroactive surface area of CuC/oxi-BNCNO/GCE was estimated as being 3 times higher than bare GCE and twice that of oxi-BNCNO/GCE. The electrooxidation of EFV on a CuC/oxi-BNCNO/GCE sensor resulted in a pH-dependant anodic peak in the potential range of 0.8 to 1.2 V vs Ag/AgCl (3M KCl). The EFV voltammetric signal increased linearly with increasing concentration of EFV in the linear dynamic range (LDR) of 0.01 – 1.0 µM and 0.5 – 20 µM with a limit of detection (LOD) and quantification (LOQ) of 1.2 and 3.97 nM, respectively. Moreover, the sensor had a sensitivity of 23 µA • cm− 2 • µM− 1 and was selective to 100-fold of interferents including heavy metal ions and other ARVs with the exception of high concentrations of nevirapine. The developed electroanalytical method was successfully applied for the determination of EFV in real samples such as wastewater influent and effluent, drinking/tap water, and a pharmaceutical formulation with recovery ranging from 97.8% to 109.5%

Half-life measurements for the 50 keV and 162 keV states in 132^{132}I

$^{132}$Te was produced via the $^{232}$Th ($\alpha$, fission ) reaction at the Variable Energy Cyclotron , Calcutta. $^{132}$Te was separated in carrier-free form from the fission products by radiochemical separation and the half-lives for the 50 keV and 162 keV states of $^{132}$I were determined to be 2.94$\pm$0.11 ns and 0.55$\pm$0.04 ns respectively. The present results differ significantly from the previously reported half-lives of 7.14 ns and 3.57 ns for the 50 keV and 162 keV states respectively

A new high background radiation area in Geothermal region of Eastern Ghats Mobile Belt (EGMB) of Orissa, India

A high natural radiation zone is investigated for the first time in a geothermal region of Eastern Ghats Mobile Belt (EGMB) of Orissa state in India. The surrounding area comprises a geothermal region which has surveyed using a portable pulsed Geiger–Muller counter. On the basis of findings of GM counter, an area was marked as a high radiation zone. Soil and rock samples collected from the high radiation zone were analyzed by ?-ray spectrometry (GRS) using NaI(Tl) detector. The radioactivity is found to be contributed mainly by thorium. Concentration of thorium is reported to be very high compared to their normal abundance in crustal rocks. Further, concentrations of 238U and 40K are also high compared to normal abundance in crustal rocks but their magnitude is comparatively less than that of thorium. The average concentrations of 238U (i.e. U(?–?)), 232Th and 40K are found to be 33, 459 ppm and 3%, respectively, in soils and 312, 1723 ppm and 5%, respectively, in the granitic rocks. Maximum concentrations of 238U, 232Th and 40K are found to be 95, 1194 ppm and 4%, respectively, in soils and 1434, 10,590 ppm and 8%, respectively, in the granitic rocks.Radioactive element emits various energies in its decay chain. High energies are utilized to estimate the concentration of actual 238U, 232Th and 40K using a NaI(Tl) detector, however, low energies are used for the same in an HPGe detector. Some of the rock samples (eight in number) were also analyzed using HPGe detector for studying the behavior of low energies emitted in the decay series of uranium and thorium. The absorbed gamma dose rate in air and external annual dose rate of the high radiation zone are calculated to be 2431 nGy/h and 3.0 mSv/y, respectively. It is approximately 10 times greater than the dose rates obtained outside the high radiation zone. The high concentration of uranium and thorium may be one of the possible heat sources together with the normal geothermal gradient for hot springs present in the region. <br/

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