ABSTRACT
An online solid phase extraction ( online-SPE) combined with ultra high performance liquid chromatography-quadrupole linear ion trap mass spectrometry (UHPLC-MS / MS-Qtrap) was established for the simultaneous identification and determination of 10 kinds of algal toxins in water samples. Multiple injections of water samples were controlled by a preset program, and the target analytes were enriched by trap column. The six-way valve was switched subsequently, and the algal toxins in the trap column were back-flushed to the analytical column for separation and analysis. The results showed that the online SPE significantly simplified pretreatment process, and the linear ion trap tandem mass spectrometry improved the sensitivity of the determination. Moreover, the establishment of enhanced product ion (EPI) scan library provided evidence for the confirmation of algal toxins. The 10 kinds of algal toxins showed a good linear relationship with correlation coefficient R2>0. 99. The limits of detection (LOD) were 0. 0015 -0. 0050 μg / L. The mean recoveries at three spiked levels of 0. 02, 0. 1, 1. 0 μg / L were from 83. 7% to 98. 5% . The method was suitable for the rapid confirmation and quantitative determination of various algal toxins in water.
ABSTRACT
A novel method was developed for the determination of the 15+1 European priority polycyclic aromatic hydrocarbons in edible oil by online solid-phase extraction coupled with high performance liquid chromatography-ultraviolet/ fluorescence detection ( online-SPE-HPLC-UV/FL-D ) . The edible oil samples were diluted with isopropyl alcohol, and then filtered. The online extraction was performed on a solid phase extraction ChromSpher Pi column (80 mmí3 mm) and the separation was carried out on a C18 reversed-phase PAH column (250 mmí4. 6 mm i. d, 5μm) using ultraviolet detection at 220 nm and fluorescence detection. Isopropyl alcohol, acetonitrile and water were served as mobile phase in gradient elution. The results showed good linearity for the 15+1 polycyclic aromatic hydrocarbons with all the correlation coefficients (R2)>0. 99. The limits of detection ( LODs ) were between 0. 03 and 12. 23 μg/kg. The recoveries of the sixteen components in the three levels of spiked samples were in the range of 65 . 3%-110 . 5% with the relative standard deviation (RSD, n=6) from 0. 1% to 9. 8%.
ABSTRACT
A method was developed for the determination of polycyclic aromatic hydrocarbons ( PAHs ) in water by HPLC coupled with online solid phase extraction ( online SPE ) . After filtered, 1 mL of a water sample was injected directly, and then trapped on the SPE column ( Acclaim PAⅡ, 50 mm × 4. 6 mm, 3 μm) for extraction and purification; finally, the trapped analytes were transferred to the analytical column (Hypersil Green PAH, 150 mm × 3 mm, 3 μm) for the separation using valve-switching technique. The mobile phase used for online SPE was water/acetonitrile at different flow rate ( 0 . 4 and 0 . 6 mL/min ) in gradient elution mode;and that used for the separation was water/acetonitrile at 0. 8 mL/min flow rate. UV wavelength was set at 254 nm for the determination of naphthalene and acenaphthylene with no/very weak fluorescent response;fluorescence detection using programmed wavelength switching in three parallel channels was used for the other PAHs. The whole analysis process including online SPE and separation was completed within 32 min. The relative standard deviation ( RSD) of 20 PAHs were all less than 0. 16% for retention time, and less than 1. 3% for peak area (n=7). The peak area had a good linearity with the sample concentration in three orders of magnitude with correlation coefficients of above 0 . 9910 . The recoveries for 0 . 05 μg/L of each analyte in tap water were in the range of 57%-140%, and for 5 . 0 μg/L of each analyte were in the range of 85%-116%. The limits of detection of the method were less than 0 . 05 μg/L ( S/N=3 ) for most PAHs.
ABSTRACT
A novel method for quantification of astragaloside IV in Radix Astragli was developed by using online SPE liquid chromatography coupled with corona charged aerosol detection( CAD) . The sample solution was loaded into Acclaim Polar AdvantageⅡC18(50 mm×4. 6 mm, 3 μm) which was selected as online SPE column. Then the cleaning process was done by using the Right one of dual gradient pumps with Methanol-water as mobile phase. Acclaim C18(150 mm×4. 6 mm, 5 μm) was selected as analytical column with acetonitrile-water as mobile phase at a flow rate of 1. 0 mL/min. The eluate containing the target from SPE column was transferred into the analytical column by heart-cutting mode. The temperature of nebulizer of corona CAD was set at 30 ℃ and the nitrogen pressure was 241. 3 kPa. The baseline separation of astragaloside IV from matrix components has been achieved. There was a good linear correlation in the range of 4 . 0-80 mg/L for astragaloside IV and the correlation coefficient was 0 . 9998 . The standard addition average recovery of astragaloside IV in Radix Astragli was 97 . 6%. It has been validated that astragaloside IV in Radix Astragli and its preparations can be quantified rapidly and accurately with this method.
ABSTRACT
A novel method was developed for the direct analysis of testosterone, androstenedione, methyltestosterone and methenolone in serum samples by fully automated online turbulent flow solid phase extraction coupled with high performance liquid chromatography-tandem mass spectrometry. An aliquot of 50 μL serum sample was preconcentrated directly on a Turboflow SPE column after centrifugation. Turboflow SPE C18-P could be used to remove serum matrix effectively. The optimum loading flow rate and elution time were 4. 0 mL/min and 1. 0 min, respectively. The linearity ranges were from 1. 0 μg/L to 100. 0 μg/L for four target compounds. The method limits of detection ( LODs) were in the range of 0. 2-0. 3 μg/L. The relative standard deviations (RSDs) ranged from 2. 9% to 14. 1% (n=5). The time for one sample analysis including extraction, separation and determination was 32 min. The proposed method has been successfully applied for the analysis of serum samples.
ABSTRACT
A method was developed for simultaneous determination of Clozapine, Quetiapine and Risperidone in human serum by fully automated online solid phase extraction ( SPE )-high performance liquid chromatography. With Capcell MF Ph-1 column as SPE cartridge and Acclaim C18 as analytical column, high selectivity could be achieved by this method according to the selective complementarity of the two columns. In the experiment, ACN-H2 O was used as the SPE mobile phase with a flow rate of 1 mL/min and ACN-10 mmol/L NH4 Ac was used as the analytical mobile phase with a flow rate of 1 mL/min. Serum samples were injected directly into the SPE column and the biological matrix was washed out with the loading solvent. By rotation of the switching valve, Clozapine, Quetiapine and Risperidone were eluted from the SPE cartridge in the back-flush mode and transferred to the analytical column by the chromatographic mobile phase. The whole time of the online SPE purification and chromatographic separation of the analytes was 18 min. Calibration curve of Clozapine with good linearity ( r=0 . 9996 ) was obtained in the range of 10-1800 μg/L in human serum, and the recoveries at low, medium and high concentration levels were 118. 4%, 105. 0% and 105 . 4%. Calibration curve of Quetiapine with good linearity ( r=0 . 9997 ) was obtained in the range of 3 . 6-640 μg/L in human serum, and the recoveries at low, medium and high concentration levels were 112. 8%, 101 . 1% and 101 . 5%. Calibration curve of Risperidone with good linearity ( r=0 . 9995 ) was obtained in the range of 0. 71-128 μg/L in human serum, and the recoveries at low, medium and high concentration levels were 100. 7%, 97. 2% and 98. 8%. In conclusion, the established automated online SPE-HPLC-UV method demonstrated good performance in terms of linearity, specificity, limits of quantification, and was successfully utilized to quantify Clozapine, Quetiapine and Risperidone in human serum.
ABSTRACT
A novel HPLC-CAD method coupled with on-line solid phase extraction ( SPE ) for the determination of erythrocin which was widely used in livestock farming was developed. After mixed with diatomite, 5. 0 g manure sample was put into the cell and extracted with hot water at 70℃ and 10. 3 MPa. An on-line SPE methodology was applied to pre-treat the sample, and the sample was seperated on an Acclaim 120 C18 column and analyzed by corona CAD detector using acetonitrile and 0. 1% formic acid as mobile phase. Good linearity for erythrocin was obtained in the range of 21-2000 μg/kg. The detection limit was 6. 3 μg/kg. The average recoveries were 79. 2%-87. 5%.
ABSTRACT
A method was developed for the determination of N-acetyl-S-( N-methylcarbamoyl ) cysteine ( AMCC) in human urine by online solid-phase extraction ( SPE )-high performance liquid chromatography ( HPLC ) . The separation of AMCC from the urine matrix was performed on AmoniPac PA Solid phase Extraction ( SPE ) column with 5 mmol/L KH2 PO4 as the mobile phase by left pump. Then the time was controlled to switch the valve to make only the section of sample containing AMCC transferred into the analytic column-Acclaim PAⅡ C18 . The determination was performed using gradient elution of 0. 1% H3 PO4 (containing 5% acetonitrile) and acetonitrile by right pump. The results showed that AMCC present good linear correlation in the range of 1 . 0-100 mg/L with a correlation coefficient of above 0 . 999 , the quantitation limit of the method was 0. 2 mg/L (with the sample inject volume =10 μL), the recoveries of spiked samples were in the range of 82 . 9%-85 . 9%, and the relative standard deviation ( n=6 ) of retention time and peak area were 0. 2% and 4. 0% respectively. Compared with offline SPE-HPLC, the proposed method was convenient, environmentally friendly, efficient and stable, and feasible for the detection of AMCC in 7 human urine samples.
ABSTRACT
Qualitative and quantitative analyses of biological samples containing drugs, toxicants and endogenous substances play an important role in the researches of life sciences, as well as in new drug discovery and development. Biological samples are characterized by complex matrix, multiple endogenous interferences, significantly lower concentrations of measured analytes compared to endogenous components and small sampling volume. Consequently, it often requires bioanalysis methods with superior specificity, high sensitivity and good reproducibility. The two-dimensional liquid chromatography (2D-LC) technique, which allows for high peak capacity, significant reduced matrix effect and carryover of complex matrix samples and automated sample pre-treatment and analysis, has been the powerful solution to the separation and analysis of biological sample and widely applied to environment, food and pharmaceutical analysis. On the basis of introduction of the principle and equipments of 2D-LC, the application of this technique in the pharmacokinetics, toxicological and biological study was reviewed.