scholarly journals Solid-Phase Extraction Cleanup and Liquid Chromatography with Ultraviolet Detection of Ephedrine Alkaloids in Herbal Products

1998 ◽  
Vol 81 (6) ◽  
pp. 1121-1127 ◽  
Author(s):  
Jeffrey A Hurlbut ◽  
Justin R Carr ◽  
Emma R Singleton ◽  
Kent C Faul ◽  
Mark R Madson ◽  
...  
Keyword(s):  
Solid Phase Extraction ◽  
Solid Phase ◽  
Phase Extraction ◽  
Isocratic Elution ◽  
Herbal Products ◽  
Ultraviolet Detection ◽  
Relative Standard ◽  
Triethyl Amine ◽  
Label Claim ◽  
Liquid Chromatographic

Abstract A solid-phase extraction (SPE) cleanup and a liquid chromatographic (LC) method with UV detection is presented for analysis of up to 7 ephedrine alkaloids in herbal products. Alkaloids from herbal products are extracted with acidified buffer, isolated on a propylsulfonic acid SPE column, eluted with a high-ionic-strength buffer, and separated by LC with detection at 255 nm. LC separation is performed by isocratic elution on a YMC phenyl column with 0.1 M sodium acetate-acetic acid (pH = 4.8) containing triethyl-amine and 2% acetonitrile. Ephedrine alkaloids are completely separated in 15 min. Average recovery of 5 common alkaloids from 3 spiked matrixes is 90%, with an average relative standard deviation (RSD) of 4.4% for alkaloid spikes between 0.5 and 16 mg/g. Average quantitation of ephedrine and pseudoephedrine from 6 herbal products is 97% of declared label claims, and average quantitation of synephrine from an herbal dietary product is 85% of label claim (RSD, 3.2%). Recoveries of synephrine, norephedrine, ephedrine, pseudoephedrine, N-methylephedrine, and N-methylpseudoephedrine spiked in 4 herbal products averaged 95%. Results of ruggedness testing and of a second laboratory validation of the procedure are also presented.

scholarly journals Determination of Penicillin G in Feeds by Liquid Chromatography with Solid-Phase Extraction

2005 ◽  
Vol 88 (3) ◽  
pp. 679-683 ◽  
Author(s):  
Matthew J Gramse ◽  
Paul E Jacobson
Keyword(s):  
Liquid Chromatography ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Reversed Phase ◽  
Penicillin G ◽  
Phase Extraction ◽  
Solid Phase Extraction Cartridge ◽  
Relative Standard ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method was developed for the determination of penicillin G in feeds. The method involves extraction of penicillin G with methanol, concentration under a stream of nitrogen, and cleanup using Phenomenex Strata-X solid-phase extraction cartridge. Analyte separation and quantification were achieved by gradient reversed-phase liquid chromatography and ultraviolet absorbance at 230 nm. Average spike recoveries for samples prepared at 3 spiking levels (25, 50, and 200 g/ton) were 96.3, 92.1, and 88.6%, respectively. The overall method precision at each of the 3 spiking levels was ≤5.39% relative standard deviation. The limits of detection and quantititation (g/ton formulation) were 3.89 and 13.0 g/ton, respectively.

scholarly journals Determination of Benzoylurea Insecticides in Apples and Pears by Solid-Phase Extraction Cleanup and Liquid Chromatography with UV Detection

1999 ◽  
Vol 82 (1) ◽  
pp. 213-216 ◽  
Author(s):  
Nicholas G Tsiropoulos ◽  
Pipina G Aplada-Sarlis ◽  
George E Miliadis
Keyword(s):  
Solid Phase Extraction ◽  
Solid Phase ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Phase Extraction ◽  
Relative Standard ◽  
Benzoylurea Insecticides ◽  
Preliminary Extraction ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method was developed and statistically validated for simultaneous determination of 5 benzoylurea insecticides (di-flubenzuron, triflumuron, teflubenzuron, flufenoxuron, and lufenuron) in apples and pears. It involves preliminary extraction with ethyl acetate–sodium sulfate and cleanup on silica solid-phase extraction cartridges using dichloromethane–2-propanol (9 + 1) as eluant. The eluate is dried under nitrogen and redissolved in methanol. Benzoylurea insecticides are determined by reversed-phase LC with gradient elution at 42°C and UV diode array detection. Recoveries from samples fortified with the 5 insecticides at 0.02–0.5 mg/kg ranged from 83 to 102% for apples and from 75 to 99% for pears. Relative standard deviations were 0–12%. Limits of detection were 0.01 mg/kg for apples and 0.02 mg/kg for pears.

Factorial Design Optimisation of Solid Phase Extraction for Preconcentration of Parabens in Wastewater Using Ultra-High Performance Liquid Chromatography Triple Quadrupole Mass Spectrometry

2020 ◽  
Vol 16 (4) ◽  
pp. 436-446
Author(s):  
Vallerie A. Muckoya ◽  
Philiswa N. Nomngongo ◽  
Jane C. Ngila
Keyword(s):  
Solid Phase Extraction ◽  
Formic Acid ◽  
Factorial Design ◽  
Solid Phase ◽  
Treatment Plant ◽  
Phase Extraction ◽  
Limit Of Quantification ◽  
Analytical Technique ◽  
Relative Standard ◽  
Simulated Wastewater

Background: Parabens are synthetic esters used extensively as preservatives and/or bactericides in personal care personal products. Objective: Development and validation of a novel robust chemometric assisted analytical technique with superior analytical performances for the determination of ethylparaben, methylparaben and propylparaben, using simulated wastewater matrix. Methods: An automated Solid Phase Extraction (SPE) method coupled with liquid chromatographymass spectrometry was applied in this study. A gradient elution programme comprising of 0.1% formic acid in deionised water (A) and 0.1% formic acid in Methanol (B) was employed on a 100 x 2.1 mm, 3.0 μm a particle size biphenyl column. Two-level (2k) full factorial design coupled with response surface methodology was used for optimisation and investigation of SPE experimental variables that had the most significant outcome of the analytical response. Results: According to the analysis of variance (ANOVA), sample pH and eluent volume were statistically the most significant parameters. The method developed was validated for accuracy, precision, Limits of Detection (LOD) and Limit of Quantification (LOQ) and linearity. The LOD and LOQ established under those optimised conditions varied between 0.04-0.12 μgL−1 and 0.14-0.40 μgL−1 respectively. The use of matrix-matched external calibration provided extraction recoveries between 78-128% with relative standard deviations at 2-11% for two spike levels (10 and 100 μgL-1) in three different water matrices (simulated wastewater, influent and effluent water). Conclusion: The newly developed method was applied successfully to the analyses of parabens in wastewater samples at different sampling points of a wastewater treatment plant, revealing concentrations of up to 3 μgL−1.

Green Dispersive Micro Solid-Phase Extraction using Multiwalled Carbon Nanotubes for Preconcentration and Determination of Cadmium and Lead in Food, Water, and Tobacco Samples

2020 ◽  
Vol 16 (4) ◽  
pp. 381-392
Author(s):  
Ayman A. Gouda ◽  
Ali H. Amin ◽  
Ibrahim S. Ali ◽  
Zakia Al Malah
Keyword(s):  
Carbon Nanotubes ◽  
Solid Phase Extraction ◽  
Multiwalled Carbon Nanotubes ◽  
Solid Phase ◽  
Certified Reference Materials ◽  
Phase Extraction ◽  
Multiwalled Carbon ◽  
Flame Atomic Absorption ◽  
Relative Standard ◽  
Separation And Preconcentration

Background: Cadmium (Cd2+) and lead (Pb2+) have acute and chronic effects on humans and other living organisms. In the present work, new, green and accurate dispersive micro solid-phase extraction (DμSPE) method for the separation and preconcentration of trace amounts of cadmium (Cd2+) and lead (Pb2+) ions in various food, water and tobacco samples collected from Saudi Arabia prior to its Flame Atomic Absorption Spectrometric (FAAS) determinations was developed. Methods: The proposed method was based on a combination of oxidized multiwalled carbon nanotubes (O-MWCNTs) with a new chelating agent 5-benzyl-4-[4-methoxybenzylideneamino)-4H- 1,2,4-triazole-3-thiol (BMBATT) to enrich and separate trace levels of Cd2+ and Pb2+. The effect of separation parameters was investigated. The validation of the proposed preconcentration procedure was performed using certified reference materials. Results: Analyte recovery values ranged from 95-102%, indicating that the method is highly accurate. Furthermore, precision was demonstrated by the relative standard deviation (RSD < 3.0%). The limits of detection were 0.08 and 0.1 μg L−1 for Cd2+ and Pb2+ ions, respectively. The preconcentration factor was 200. Conclusion: The proposed method was used for the estimation of Cd2+ and Pb2+ ion content in various real samples, and satisfactory results were obtained. The proposed method has high adsorption capacity, rapid adsorption equilibrium, extremely low LODs, high preconcentration factors and shortens the time of sample preparation in comparison to classical SPE.

Development of a solid-phase extraction – spectrofluorimetric method for trace glutathione determination

2011 ◽  
Vol 89 (4) ◽  
pp. 517-523 ◽  
Author(s):  
Ke-Jing Huang ◽  
Cong-Hui Han ◽  
Ying-Ying Wu ◽  
Chao-Qun Han ◽  
De-Jun Niu ◽  
...  
Keyword(s):  
Solid Phase Extraction ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Signal To Noise Ratio ◽  
Calibration Graph ◽  
Extraction Column ◽  
Phase Extraction ◽  
Selective Reaction ◽  
Spectrofluorimetric Method ◽  
Relative Standard

A simple and efficient solid-phase extraction – spectrofluorimetric method has been developed to determine glutathione (GSH). Fluorescent probe N-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-yl)methyl)iodoacetamide (BODIPY Fl-C1-IA) was used as the derivatization reagent. The procedure was based on a BODIPY Fl-C1-IA selective reaction with GSH to form the highly fluorescent product BODIPY Fl-C1-IA–GSH, using a solid-phase extraction column and spectrofluorimetric determination. The variables affecting analytical performance were studied and optimized. The calibration graph using the preconcentration system for GSH was linear over the range of 1–200 nmol/L with a limit of detection of 0.05 nmol/L (signal-to-noise ratio = 3). The relative standard deviation for six replicate determinations of GSH at the 100 nmol/L concentration level was 3.9%. The method was applied to water samples and average recoveries between 87.5% and 111.5% were obtained for spiked samples.

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