ABSTRACT
OBJECTIVE:To determine the content of urea in Urea [13C] capsules by high performance cation-exchange chroma-tography (HPCEC). METHODS:The determination was performed on Zorbax 300 SCX column with mobile phases consisting of acetonitrile-0.1% phosphoric acid (20:80,V/V) at the flow rate of 1.0 mL/min. The detection wavelength was set at 200 nm and column temperature was 35 ℃. The sample size was 20 μL. RESULTS:The linear range of urea was 0.0039-1.0030 mg/ml(r=0.9997). The limit of quantitation was 3.918 μg/mL and the limit of detection was 0.975 μg/mL. RSDs of precision,stability and repetitive test were all lower than 2.0%. The recovery ranged 99.3%-101.0%(RSD=0.67%,n=9). CONCLUSIONS:The meth-od is simple,rapid,sensitive and suitable for the content determination of urea in Urea [13C] capsules.
ABSTRACT
A method of on-line solid phase extraction ( SPE )-two dimensional liquid chromatography electrospary-tandem mass spectrometric method was established for the determination of Teicoplanin concentrations in human cerebrospinal fluid. Cerebrospinal fluid samples were treated by the on-line SPE treatment, and analyzed by LC-MS/MS. The chromatographic separation was performed on a Shiseido CAPCALL-PAK C18 column with gradient elution by using 25 mmol/L ammonium acetate ( pH 6. 0 )-acetonitrile as mobile phases, and the flow rate of 1 mL/min. Detection was carried out under the selected reaction monitoring ( SRM) in positive ionization mode with scopolamine hydrobromide as internal standard. Matrix-matched calibration curves with good correlation coefficients (R2=0. 9993, n=6) were obtained in the concentration range of 25-5000 μg/L. The average recoveries varied from 100. 8% to 109. 9%. The intra-and inter-day precisions were less than 6%. The method is proved to be rapid, sensitive, accurate, and suitable to determine Teicoplanin concentrations in human cerebrospinal fluid.
ABSTRACT
An on-line two dimensional liquid chromatographic (2D-LC) method was established by using an ultimate dual gradient liquid chromatography, three chromatographic columns and valve-switching technology to detect 2460A in trichoderma hazianum fermentation liquor. MF C8 column (10 mm×4. 6 mm, 5. 0 μm) was used as purification column and MG C18 column (20 mm×4. 6 mm, 5. 0 μm) was used as enriching column. Methanol and water were used as mobile phase with a gradient elution at a flow rate of 2. 0 mL/min. The sample was separated on the Thermo Hypersil GOLD C18 column (250 mm×4. 6 mm, 5. 0μm) maintained at 40 ℃ using methanol and water. The flow rate was 1. 0 mL/min and 1. 0 mL sample was injected into the 2D-LC system. The detection wavelength was 424 nm. The whole analytical time was less than 60 min. The standard curve was linear over the 2460A concentration range of 0. 0025-10. 0 mg/L(r=0. 9981, n=8). The limit of detection was calculated to be 1 . 2μg/L ( S/N=3 ) and the limit of quantification was calculated to be 2 . 5 μg/L ( S/N=10 ) . The average recoveries varied from 88 . 0% to 104 . 4%.