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Kanchi Suvardhan Kailasa Suresh Kumar Dasari Rekha Pantrangam Subrahmanyam Kapuvedi Kiran Bellum Jayaraj Surasura Ramanaiah Kandhukuri Janardhanam Pattium Chiranjeevi 《Mikrochimica acta》2007,157(3-4):237-244
Cloud point extraction was applied as a method for preconcentration of rhodium after formation of a complex with 2-propylpiperidine-1-carbodithioate
(2-PPC), and later determined by flame atomic absorption spectrometry using TritonX-114 as surfactant. Rhodium was complexed
with 2-PPC in an aqueous phase and kept for 15 min in a thermostatted bath at 40 °C. Separation of the two phases was accomplished
by centrifugation for 15 min at 4000 rpm. The chemical variables affecting the cloud point extraction were optimized and successfully
applied to rhodium determination in various water samples. Under optimized conditions, the preconcentration system (100 mL
sample) permitted an enhancement factor of 50. The detection limits obtained under optimal conditions was 0.052 ng mL−1. The extraction efficiency was investigated at different rhodium concentrations (7.0–42.0 μg mL−1), and good recoveries (96.42–99.14%) were obtained using this method. It has been applied to the determination of rhodium
in water and was compared with reported methods in terms of Student’s ‘t’-test and variance ratio ‘f’-test. 相似文献
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Ensemble averaging schemes are applied within the PPP model to calculate excitation spectra of free conjugated hydrocarbon radicals and further, more general forms of the pairing and particle-hole properties for conjugated hydrocarbons are shown to be valid. 相似文献
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REKHA Dasari SUVARDHAN Kanchi KUMAR Kailasa Suresh JAYARAJ Bellum CHIRANJEEVI Pattium 《中国化学》2006,24(8):1095-1100
A facile,rapid and sensitive spectrophotometric method was developed for the determination of carbaryl in itsformulations,water and grain(rice and wheat)samples with newly synthesised reagent.The proposed method wasbased on the alkaline hydrolysis of carbaryl pesticide and thus resulted 1-naphthol was coupled with diazotised4,4'-methylene-bis-m-nitroaniline in basic medium(pH 9)to give red colored product having λ_(max)480 nm for dia-zonium method(DM)or 1-naphthol reacts with 4,4'-methylene-bis-m-nitroaniline in the presence of oxidising agentpotassium dichromate(K_2Cr_2O_7)to give red colored product having λ_(max)510 nm for oxidation method(OM).Theformation of colored derivatives with the coupling agent is instantaneous and stable for 48 h(DM)and 32 h(OM)respectively.Beer's law was obeyed in the concentration range of 0.2—10.0 μg·mL~(-1)for DM and 0.2—0,150μg·mL~(-1)for OM.The proposed methods are sensitive,easy to operate and permitted for the determination of car-baryl with detection limits of 0.028 μg·mL~(-1)for DM and 0.024 μg·mL~(-1)for OM respectively.The experimentalresults indicate that the procedure can eliminate the fundamental interferences caused by other pesticides andnon-target ions,which made the methods more sensitive and selective.The method was applicable to the determina-tion of carbaryl residue in water and food grain samples up to μg level. 相似文献
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