Pre-concentration of thorium and neodymium isotopes using Nobias chelating resin: Method development and application to chromatographic separation

Talanta ◽  
2019 ◽  
Vol 202 ◽  
pp. 600-609 ◽  
Author(s):  
Habacuc Pérez-Tribouillier ◽  
Taryn L. Noble ◽  
Ashley T. Townsend ◽  
Andrew R. Bowie ◽  
Zanna Chase
2016 ◽  
Vol 9 (1) ◽  
pp. 30 ◽  
Author(s):  
Darshan Bhatt ◽  
B. Rajkamal

Objective: The present work aimed to develop a simple, rapid, specific and precise ultra-performance liquid chromatography-tandem mass spectrophotometric (LC–MS/MS) validated method for quantification of sofosbuvir and internal standard (ISTD) Sofosbuvir-d3 in human plasma.Methods: Samples prepared by employing liquid-liquid extraction (LLE) using 2.5 ml of ethyl acetate. Chromatographic separation was achieved on Gemini 5µ C18, 50 x 4.6 mm column using a mixture of 0.1% (v/v) formic acid in water to methanol at a ratio of 30:70 v/v as the mobile phase. The flow rate was 0.50 ml/min. The LC eluent was split, and approximately 0.1 ml/min was introduced into Tandem mass spectrometer using turbo Ion Spray interface at 325 °C. Quantitation was performed by transitions of 428.35/279.26 (m/z) for sofosbuvir and 431.38/282.37 (m/z) for sofosbuvir-d3.Results: The concentrations of ten working standards showed linearity between 4.063 to 8000.010ng/ml (r2 ≥ 0.9985). Chromatographic separation was achieved within 2 min. The average extraction recoveries of three quality control concentrations were 75.36% for sofosbuvir and were within the acceptance limits. The coefficient of variation was ≤15% for intra-and inter-batch assays. The %CV of ruggedness ranges 0.35% and 3.09%. The % stability of short term and long term stock solution stability studies was found to be 97.25% and 98.81% respectively.Conclusion: The results obtained for specificity, linearity, accuracy, precision, ruggedness and stability studies were within the acceptance limits. Thus the validated economical method was applied for pharmacokinetic studies of sofosbuvir.


2011 ◽  
Vol 1218 (20) ◽  
pp. 2923-2928 ◽  
Author(s):  
I.M. Ismail ◽  
M. Ibrahim ◽  
H.F. Aly ◽  
M. Nomura ◽  
Y. Fujii

1996 ◽  
Vol 68 (9) ◽  
pp. 1517-1520 ◽  
Author(s):  
Yoshinori Inoue ◽  
Hiroki Kumagai ◽  
Yoshiko Shimomura ◽  
Toshiro Yokoyama ◽  
Toshishige M. Suzuki

2016 ◽  
Vol 9 (1) ◽  
pp. 37 ◽  
Author(s):  
D. Atul Vasanth ◽  
B. Rajkamal

Objective: The present work aimed to develop a simple, rapid, specific and precise liquid chromatography-tandem mass spectrophotometric (LC–MS/MS) validated method for quantification of pomalidomide and internal standard (ISTD) Fluconazole in human plasma.Methods: 50 µl of 0.1% formic acid was added to plasma samples prior to liquid-liquid extraction (LLE) using 2.5 ml of ethyl acetate. Chromatographic separation was achieved on Xterra, RP18, 5 µ (50 x 4.6 mm) column using a mixture of 0.1% (v/v) formic acid in water to methanol at a ratio of 12:88, v/v as the mobile phase. The flow rate was 0.50 ml/min. The LC eluent was split, and approximately 0.1 ml/min was introduced into Tandem mass spectrometer using turbo Ion Spray interface at 325 °C. Quantitation was performed by transitions of m/z 260.1 precursor ion to the m/z 148.8 for pomalidomide and m/z 307.1/238.0 for fluconazole.Results: The concentrations of nine working standards showed linearity between 9.998 to 1009.650 ng/ml (r2 ≥ 0.9968). Chromatographic separation was achieved within 2 min. The average extraction recoveries of three quality control concentrations were 53.86% for pomalidomide and were within the acceptance limits. The coefficient of variation was ≤15% for intra-and inter-batch assays. The %CV of ruggedness ranges 1.32 to 4.03. The % stability of short term and long term stock solution stability studies was found to be 99.01% and 98.49% respectively.Conclusion: The results obtained for specificity, linearity, accuracy, precision, ruggedness and stability studies were within limits. Thus the validated economical method was applied for pharmacokinetic studies of pomalidomide.


2020 ◽  
Vol 58 (6) ◽  
pp. 504-510
Author(s):  
Martin N Saad ◽  
Hebatallah M Essam ◽  
Eman S Elzanfaly ◽  
Sawsan M Amer

Abstract The growing technology of stationary phase chemistry has a great impact on the chromatographic system performance and analysis economics. In this context, a simple rapid reversed phase high-performance liquid chromatography method development is presented for the analysis of gatifloxacin (GFN) and dexamethasone sodium phosphate (DSP) in their ophthalmic formulation. A two-step optimization approach has been conducted using optimum chromatographic conditions as well as proper selection of stationary phase. The chromatographic separation was carried out using sodium phosphate buffer pH 3.0 ± 0.1 and acetonitrile 72:28 v/v, respectively, with flow rate 1 mL min−1 and simultaneous detection at 243 nm. Three different column technologies were investigated at the optimum set of the chromatographic conditions: Xbridge® bridged ethylene hybrid silica, Kinetex™ Core-Shell and the Onyx™ Monolithic stationary phase. The monolithic column has shown better chromatographic separation, based on system suitability testing as well as shorter analysis time and sensitivity. The proposed method was validated according to International Conference on Harmonization guidelines. The linearity was achieved for GFN and DSP in the range 0.58–120 μg mL−1 and 0.50–120 μg mL−1, respectively, with acceptable accuracy, precision and selectivity.


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