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  • Author or Editor: M. Asif x
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Abstract  

Adsorption behavior of molybdate on acidic alumina was studied at boiling water bath temperature (~100 °C). Various parameters affecting the adsorption of molybdenum, such as pH, amount of molybdenum, incubation period, etc., were determined. A 99mTc generator was prepared by adsorbing low specific activity 99Mo (150 mg) on 1 g alumina. Elutions were carried out with saline. Performance of the generator such as 99Mo breakthrough, aluminum contents, pH, elution profile, radiochemical purity, and labeling efficiency of kits were checked.

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Abstract  

The radioactive study of Ni–NiS bead fire-assay followed by neutron activation analysis showed nearly quantitative collection of the platinum group elements and gold in the bead. However, there was clearly some loss of gold and ruthenium at the dissolution and filtration stage. A preliminary study of the radiochemical fire-assay method indicates that the technique could overcome the problem of losses. Chemical carrier behaves in the same way as platinum metal concentrate during the analytical procedure and could be used to evaluate yields during each determination. When applied to rock samples, the radiochemical fire-assay gives good sensitivity and could be applied to the determination of nanogram concentrations of the platinum group elements without the problem of high blank values from reagents.

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The insecticides are broadly divided into organophosphates, organochlorines, carbamates, and pyrethroids. Various chromogenic spray reagents have been reported for the identification of these classes of pesticides and insecticides. Some of them are specific and some are general for a particular class of insecticides. The large volume of insecticides belong still to the organophosphates which can be divided into thio and non-thio insecticides, on the basis of the presence or absence of a sulfur atom. We here present alkaline sodium nitroprusside as a simple chromogenic spray reagent which reacts with only a specific type of organothiophosphorus insecticides and not all organothiophosphorus insecticides.

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Organometallic compounds find wide applications such as in catalyses, syntheses, and also in biochemistry. Some of them can be used for the analysis of trace quantities of organic compounds which are regarded as toxic to human beings. Many pesticides have very low lethal dose (LD50) which could be fatal to humans, even in small quantities. The traces of many pesticides are being reported to be present in vegetables, fruits, and even in processed foods. Monocrotophos is one such pesticide which is approved for use in India and has caused many suicidal and accidental poisoning cases. Thus, a simple and sensitive method was necessary for its detection. We, in this study, reveal the application of sodium nitroprusside for the analysis of monocrotophos using a novel reaction with simple, cost-effective, but fast and reliable thin-layer chromatography technique.

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The comparisons among the 6 selection indices S 1 , S 2 , S 3 (simultaneous selection indices comprising of X 1 only; X 1 +X 5 and X 1 +X 2 +X 3 +X 4 respectively as their component traits), S 4 (Rank summation index), S 5 (Baker’s standard deviation index) and S 6 (Elston’s weight free index) were made involving 4 primary cold tolerance traits namely field emergence per cent (X 1 ), fresh seedling root mass (X 2 ), seedling dry weight (X 3 ), days to 50% silk emergence (X 5 ) along with grain yield ha −1 (X 4 ). Highly significant rank correlations of proposed selection indices conferred the suitability in use of one index if substituted for other, to score the genotypes for selection. Selection differentials for all the indices were generally positive with respect to the traits X 1 , X 2 , X 3 and X 4 except S 2 which, was accompanied with negative differentials for X 2 , X 3 and X 4 . S 1 was found to be an important cold tolerance trait depicting not so less differentials compared to other traits and had positive differentials under each selection criteria. Index S 6 was efficient in selecting early silking varieties with high yield and tolerance to cold. The populations NDSM 8 WN, NDSAB (MER), NDSLC and land races GL20W and Dawar-2 showed high degree of cold tolerance among 67 genotypes evaluated and showed at par results with the C 15 check which was top ranking under 5 out of 6 selection used.

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A novel chromogenic spray reagent “hydralazine” (phthalazin-1-ylhydrazine) is reported for thin-layer chromatographic (TLC) detection and identification of synthetic pyrethroids cypermethrin, deltamethrin, and λ-cyhalothrin from their dilute commercial formulations ranging from 2.5% to 25%. Alkaline hydralazine forms orange-yellow hydrazones with these insecticides at room temperature and does not require any further treatment. Reaction mechanism is discussed. The necessary TLC parameters like pH and concentration of analyte are also suggested for the efficient detection of these toxic pyrethroid insecticides.

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