Search results for "Solid Phase Extraction"
showing 10 items of 297 documents
Sample Preparation to Determine Pharmaceutical and Personal Care Products in an All-Water Matrix: Solid Phase Extraction
2020
© 2020 by the authors.
Polish Yellow Sweet Clover (Melilotus officinalis L.) Honey, Chromatographic Fingerprints, and Chemical Markers
2017
A case study of Polish Melilotus officinalis honey was presented for the first time. Gas chromatography–mass spectrometry (GC-MS) (after steam distillation, Soxhlet extraction, ultrasonic solvent extraction, and solid phase extraction (SPE)) and targeted high performance liquid chromatography with a photodiode array detector (HPLC-PAD) were applied to determine the characteristic components of honey. While ubiquitous in most honeys, carbohydrates, terpene derivatives, and phenylacetic acid dominated in the Soxhlet extracts (25.54%) and in the application of SPE (13.04%). In addition, lumichrome (1.85%) was found, and may be considered as a marker of this honey. Due to the presence of these …
Liquid Chromatographic Analysis of Amphetamine and Related Compounds in Urine Using Solid-Phase Extraction and 3,5-Dinitrobenzoyl Chloride for Deriva…
1997
A chromatographic method for the analysis of amphetamine and related compounds in urine using 3,5-dinitrobenzoyl chloride (3,5-DNB) as a labeling reagent is presented. This assay is based on the employment of solid-phase extraction (SPE) cartridges for sample cleanup and derivatization. Experimental conditions are optimized for the simultaneous derivatization of ephedrine, norephedrine, pseudoephedrine, beta-phenylethylamine, amphetamine, methamphetamine, and 3-phenylpropylamine. The derivatives formed are separated in a LiChrospher 1000 RP18 (125 x 4-mm i.d., 5-microns film thickness) analytical column using a water-acetonitrile gradient elution and detected at 254 nm. Derivatization in C1…
Sequential-injection determination of traces of disodium phenyl dibenzimidazole tetrasulphonate in urine from users of sunscreens by on-line solid-ph…
2005
Abstract A sensitive and selective method to determine disodium phenyl dibenzimidazole tetrasulphonate (PDT) in the urine of sunscreen users, which is suitable for studies on body accumulation/excretion is proposed. On-line solid-phase extraction allows the analyte to be retained and subsequentely eluted, using a strong anion exchange (SAX) microcolumn. Standard addition calibration was carried out with only one standard. The wavelengths of excitation and emission were 330 and 454 nm, respectively. The method allows PDT to be determined in both, spiked and unspiked human urine samples, without any pre-treatment. Results obtained for spiked urine samples (40–200 ng ml −1 ) showed the accurac…
Determination of 3-(4′-methylbenzylidene)camphor and its metabolite 3-(4′-carboxybenzylidene)camphor in human semen by solid-phase extraction and liq…
2015
An analytical method for the determination of the controversial UV filter 3-(4′-methylbenzylidene)camphor (MBC) and its metabolite 3-(4′-carboxybenzylidene)camphor (CBC) in human semen is presented. The method is based on the simultaneous hydrolysis of phase II conjugates and protein precipitation, followed by solid-phase extraction (SPE) and liquid chromatography tandem mass spectrometry (LC-MS/MS) detection. The proposed method was validated by analyzing spiked analyte-free human semen samples. Matrix-matched calibration using an analyte-free semen pool was employed. Satisfactory recoveries (92–114%) were obtained using this calibration methodology, thus showing the accuracy of the propos…
Recent developments and future trends in solid phase microextraction techniques towards green analytical chemistry.
2013
Solid phase microextraction find increasing applications in the sample preparation step before chromatographic determination of analytes in samples with a complex composition. These techniques allow for integrating several operations, such as sample collection, extraction, analyte enrichment above the detection limit of a given measuring instrument and the isolation of analytes from sample matrix. In this work the information about novel methodological and instrumental solutions in relation to different variants of solid phase extraction techniques, solid-phase microextraction (SPME), stir bar sorptive extraction (SBSE) and magnetic solid phase extraction (MSPE) is presented, including prac…
New micromethod combining miniaturized matrix solid-phase dispersion and in-tube in-valve solid-phase microextraction for estimating polycyclic aroma…
2008
Abstract Miniaturized matrix solid-phase dispersion (MSPD) was developed for the extraction of common polycyclic aromatic hydrocarbons (PAHs) from bivalve samples (100 mg, dry weight). Additional clean-up and analyte enrichment was accomplished by in-tube solid-phase microextraction (SPME). For this purpose the extracts collected after MSPD were diluted with water and injected into a capillary column coated with the extractive phase. This capillary column was connected to the analytical column by means of a switching valve. Separation and quantification of the PAHs were carried out using a monolithic LC column and fluorescence detection. Since the in-tube SPME device allowed the processing …
Sensitive determination of ethacrynic acid in urine samples by reversed-phase liquid chromatography with ultraviolet detection using solid-phase extr…
1992
Abstract A rapid method is described for the identification and determination of ethacrynic acid in human urine samples by liquid chromatography with UV detection, the retention time of the analyte being 4.9 min. The samples were previously conditioned using C 18 solid-phase extraction columns and chromatographed on an HP-LiChrospher RP C 18 column (5 μm; 125 mm × 4 mm i.d.) with gradient elution with acetonitrile-acetate buffer (pH 4). The detector was set at 275 nm and furosemide was used as an internal standard. The procedure was applied to the determination of ethacrynic acid at concentrations of 0.01-10 μg ml -1 and the limit of detection was 6 ng ml -1 .
A solid-phase extraction liquid chromatography-tandem mass spectrometry method for the percutaneous absorption assessment of 3-(4′-methylbenzylidene)…
2013
The UV filter 3-(4′-methylbenzylidene)camphor (MBC) is a common ingredient in sunscreen cosmetic products. However, different in vitro and in vivo studies suggest that MBC can cause endocrine disrupting effects. This report focuses on the development of an analytical method based on solid-phase extraction (SPE) prior to liquid chromatography tandem mass spectrometry (LC-MS/MS) for the determination of MBC and its main phase I metabolite, named 3-(4′-carboxybenzylidene)camphor (CBC), in urine from users of sunscreen cosmetic products containing MBC. The formation of phase II metabolites (i.e., glucuronide and sulphate conjugates) was also considered by carrying out an enzymatic hydrolysis of…
Development of a fully automated sequential injection solid-phase extraction procedure coupled to liquid chromatography to determine free 2-hydroxy-4…
2010
Abstract 2-Hydroxy-4-methoxybenzophenone and 2-hydroxy-4-methoxybenzophenone-5-sulphonic acid, commonly known as benzophenone-3 (BZ3) and benzophenone-4 (BZ4), respectively, are substances widely used as UV filters in cosmetic products in order to absorb UV radiation and protect human skin from direct exposure to the deleterious wavelengths of sunlight. As with other UV filters, there is evidence of their percutaneous absorption. This work describes an analytical method developed to determine trace levels of free BZ3 and BZ4 in human urine. The methodology is based on a solid-phase extraction (SPE) procedure for clean-up and pre-concentration, followed by the monitoring of the UV filters by…