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S. Chhillar R. Acharya R. K. Mishra C. P. Kaushik P. K. Pujari 《Journal of Radioanalytical and Nuclear Chemistry》2017,312(3):567-576
Particle induced gamma-ray emission (PIGE) method using 4 MeV proton beam was utilized to analyze two types of barium borosilicate glass (BaBSG) samples for quantification of concentrations of low Z elements. The in situ current normalization method was applied in the analysis of eight samples containing varying concentration of F along with Si, B and Na. Charge normalized PIGE method was applied to determine concentrations of above low Z elements including Li and Al in samples having simulated nuclear waste from reprocessing of thoria spent fuel. Synthetic samples and NIST SRMs were used for method validation. 相似文献
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《Spectrochimica Acta Part B: Atomic Spectroscopy》2006,61(10-11):1135-1140
Recently there is a growing interest in low Z elements such as carbon, oxygen up to sulphur and phosphorus in biological specimen. Total reflection X-ray fluorescence (TXRF) spectrometry is a suitable technique demanding only very small amounts of sample. On the other side, the detection of low Z elements is a critical point of this analytical technique. Besides other effects, self absorption may occur in the samples, because of the low energy of the fluorescence radiation. The calibration curves might be not linear any longer. To investigate this issue water samples and samples from human cerebrospinal fluid were used to examine absorption effects. The linearity of calibration curves in dependence of sample mass was investigated to verify the validity of the thin film approximation. The special requirements to the experimental setup for low Z energy dispersive fluorescence analysis were met by using the Atominstitute's TXRF vacuum chamber. This spectrometer is equipped with a Cr-anode X-ray tube, a multilayer monochromator and a SiLi detector with 30 mm2 active area and with an ultrathin entrance window. Other object on this study are biofilms, living on all subaqueous surfaces, consisting of bacteria, algae and fungi embedded in their extracellular polymeric substances (EPS). Many trace elements from the water are bound in the biofilm. Thus, the biofilm is a useful indicator for polluting elements. For biomonitoring purposes not only the polluting elements but also the formation and growth rate of the biofilm are important. Biofilms were directly grown on TXRF reflectors. Their major elements and C-masses correlated to the cultivation time were investigated. These measured masses were related to the area seen by the detector, which was experimentally determined. Homogeneity of the biofilms was checked by measuring various sample positions on the reflectors. 相似文献
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A new, simple, sensitive and specific reversed-phase high performance liquid chromatographic (HPLC) method using ultraviolet detection was developed and validated for the analysis of CPT-11 (lambda(max)=254 nm, 365 nm) and its major active metabolite, SN-38 (lambda(max)=380 nm) in rat plasma and bile. The sample pre-treatment from plasma involved a single protein precipitation step with cold acetonitrile. In case of bile, liquid-liquid extraction with dichloromethane: tert-butyl methyl ether (3:7) was carried out. Topotecan, a structurally related camptothecin, was used as an internal standard. An aliquot of 50 microL was injected onto a C-18 column. The chromatographic separation was achieved by gradient elution consisting of acetonitrile and water (pH 3.0 adjusted with 20% o-phosphoric acid) at a flow rate of 1.0 ml/min. Total run time for each sample was 30 min. All the analytes viz. topotecan, CPT-11, SN-38 were well separated with retention times of 11.4, 13.4 and 15.5 min, respectively. Method was found to be selective, linear (R(2) approximately 0.999), accurate (recovery+/-15%) and precise (<5% C.V.) in the selected concentration ranges for both the analytes. The quantification limit for CPT-11 was 40 ngml(-1) and for SN-38 was 25 ngml(-1). The percent extraction efficiency was approximately 97% for CPT-11 and SN-38 from plasma while extraction recovery of CPT-11 and SN-38 from bile was approximately 70% and approximately 60%, respectively. The method was successfully used to determine plasma and biliary excretion time profiles of CPT-11 and SN-38, following oral and intravenous CPT-11 administration in rats. In the present study, irinotecan showed an absolute bioavailability of 30% as calculated from the pharmacokinetic data. 相似文献