The solvent extraction behaviour of zinc from aqueous hydrochloric acid solutions using trilaurylamine N-oxide in toluene has been studied. The distribution ratios have been studied as a function of concentration of acid and extractant. The effects of foreign agents such as nitrate, sulphate, chloride, acetate, citrate, oxalate, and ascorbic acid on the extraction of zinc from hydrochloric acid solution are also determined.
The activation cross-sections for sixteen (n, p) and (n, α) reactions on rare earth nuclides were measured at 14.8 MeV neutron
energy. A Ge(Li) detector was used for the radioactivity measurements. The measured cross-sections are compared with the semi-empirical
predictions of LEVKOVSKII3 and BAYHURST and PRESTWOOD.16
An extraction system consisting of trilaurylamine N-oxide and benzene has been identified as a possible extractant for tracer arsenic (<10–3 M) from hydrochloric or sulfuric acid solutions with or without iodide. Benzene alone is less efficient as an extractant for arsenic when compared with trilaurylamine oxide dissolved in benzene. The mechanism of extraction is attributed to the formation of hydrated AsCl3, while the iodide complex is most probably AsI
. The role of the solvent and the other parameters affecting the extraction have been investigated. The results have been employed to determine arsenic in water samples by spectrophotometry using the molybdenum blue method. The extraction procedure was used for the analysis of 10 ml water samples containing 0.2–0.5 g of arsenic.
Large-scale production of 131I in a nuclear reactor, the gaseous nature of 131I, and its selective uptake by the human thyroid gland, make this radioisotope a health hazard in the event of a nuclear accident. The maximum concentration of 131I in drinking water has been set at 1 pCi/l. Human ingestion of 131I through the grass-cow-milk pathway makes milk an environmentally significant matrix to be monitored for. In this paper, we report a simple and a rapid radiochemical procedure for the analysis of 131I in water and milk samples. A quick single-step separation on anion-exchange resin concentrates radioiodine from large sample volumes. The resin is then directly counted in the cavity of a low-background well-type HPGe detector that has high counting efficiency for X-rays and low-energy -radiation. Chemical recovery is evaluated from the intensity of the 29.6 keV X-rays of the 129I spike, and 131I is assayed through the intensity of its 364.5 keV g-peak. The method's minimum detection limit is 0.5 pCi 131I based on a 1 liter sample and a 200-minute count.
Authors:P. Parekh, A. Bari, T. Semkow, and M. Torres
It is imperative to use a leak-proof container for counting liquid sample to prevent contamination of costly gamma detectors. We report in this technical note a sealant that ensures no leak. It is a vinyl adhesive sealant used for household purposes, marketed by Gloucester Co., Inc, Franklin, MA under the trade name of Phenoseal (translucent variety). This sealant was superior to other sealants studied because it cures quickly, peels off easily after counting, and contains no detectable radioactivity. We have thoroughly tested this sealant in our laboratory and successfully employed it in the routine analysis of environmental liquid samples.
Authors:V. K. Mahajan, S. B. Bari, A. A. Shirkhedkar, and S. J. Surana
A new simple, accurate, precise, rapid, and selective densitometric TLC method has been established for simultaneous analysis of aceclofenac, paracetamol, and chlorzoxazone in tablets. Identification and quantification were performed on 10 cm × 10 cm aluminium-backed TLC plates coated with 0.2 mm layers of silica gel 60 F254, previously washed with methanol, and using toluene-2-propanol-ammonia 4:4:0.4 (υ/υ) as mobile phase. Detection was performed at 274 nm. The RF values of aceclofenac, paracetamol, and chlorzoxazone were 0.28 ± 0.01, 0.72 ± 0.02, and 0.51 ± 0.02, respectively. Calibration plots were linear in the range 400–1400 ng per band for aceclofenac, 2000–7000 ng per band for paracetamol, and 1000–3500 ng per band for chlorzoxazone, with correlation coefficients, r, 0.9995, 0.9993, and 0.9996, respectively. Recovery of aceclofenac, paracetamol, and chlorzoxazone were 99.54–100.44, 100.02–100.47, and 99.39–99.84%, respectively. The suitability of densitometric TLC for quantitative analysis of these compounds was proved by validation in accordance with the requirements of ICH Guidelines.
Authors:P. Parekh, T. Semkow, A. Bari, M. Torre, D. Haines, P. Harris, E. Fielman, and M. Kitto
A low-background well-type high-purity germanium detector system, with high counting efficiencies for X-rays and low-energy
g-rays, was used to determine several radionuclides of environmental, biomedical, or geological interest. These included 125I, 129I, 210Pb, 226Ra, 234Th (daughter of 238U), 239Pu, 240Pu and 241Am. Methods were devized for their determinations in diverse environmental matrices or under laboratory procedural conditions.
Counting efficiencies and minimum detectable activities for each nuclide were determined under the experimental conditions.
These methods are being applied to our service analysis.