Search results for "Derivatization"
showing 10 items of 215 documents
Urine polyamines determination using dansyl chloride derivatization in solid-phase extraction cartridges and HPLC
1999
The derivatization of biogenic amines such as putrescine, cadaverine, spermidine and spermine with dansyl chloride in solid phase extraction cartridges is described. Different types of filling materials were tested in order to have the highest retention of the different analytes. The best results were obtained by using C18 cartridges. The optimal conditions were: amine solution buffered at pH 12, 2 mM dansyl chloride (acetone-bicarbonate solution 20 mM (pH 9-9.5), 2 + 3 v/v) as reagent concentration, room temperature and 30 min reaction time. The developed procedure was applied to the determination of these polyamines in urine samples from healthy controls and cancer patients using HPLC wit…
Determination of atranol and chloroatranol in perfumes using simultaneous derivatization and dispersive liquid-liquid microextraction followed by gas…
2013
Abstract A new analytical method based on simultaneous derivatization and dispersive liquid–liquid microextraction (DLLME) followed by gas chromatography–mass spectrometry (GC–MS), for the determination of the allergenic compounds atranol and chloroatranol in perfumes, is presented. Derivatization of the target analytes by means of acetylation with anhydride acetic in carbonate buffer was carried out. Thereby volatility and detectability were increased for improved GC–MS sensitivity. In addition, extractability by DLLME was also enhanced due to a less polar character of the solutes. A liquid–liquid extraction was performed before DLLME to clean up the sample and to obtain an aqueous sample …
Evaluation of C18 adsorbent cartridges for sampling and derivatization of primary amines in air
2004
Abstract The sampling efficiency of C18 solid-phase extraction cartridges was investigated for methylamine, ethylamine, propylamine, butylamine and pentylamine, in air. Determination of these analytes was based on derivatization with o-phthaldialdehyde–N-acetylcysteine (OPA–NAC) on the solid support and fluorescence detection at λexcitation=330 nm and λemission=440 nm of the eluted derivatives. The calibration model derived from aqueous standards was statistically comparable with the calibration model for air standards. Aqueous amines can be used as standards. The method was useful for calculating short-term exposure limits (STEL). A sampling time of 15 min at 30 ml min−1 was employed. Good…
Quantification of nortriptyline in plasma by HPLC and fluorescence detection
2009
Abstract A simple, sensitive and specific high-performance liquid chromatography method has been developed for the determination of nortriptyline (NT) in plasma samples. The assay involved derivatization with 9H-fluoren-9-ylmethyl chloroformate (Fmoc-Cl) and isocratic reversed-phase (C 18 ) chromatography with fluorescence detection. The developed method required only 100 μl of plasma sample, deproteinized and derivatized in one step. Calibration curves were lineal over the concentration range of 5–5000 ng/ml. The derivatization reaction was performed at room temperature in 20 min and the obtained NT derivative was stable for at least 48 h at room temperature. The within-day and between-day…
A microanalytical method for ammonium and short-chain primary aliphatic amines using precolumn derivatization and capillary liquid chromatography.
2007
Abstract A new microscale method is presented for the determination of ammonium and primary short-chain aliphatic amines (methylamine, ethylamine, propylamine, n -butylamine and n -pentylamine) in water. The assay uses precolumn derivatization with the reagent o -phthaldialdehyde (OPA) in combination with the thiol N -acetyl- l -cysteine (NAC), and capillary liquid chromatography with UV detection at 330 nm. The described method is very simple and rapid as no preconcentration of the analytes is necessary, and the volume of sample required is only 0.1 mL. Under the proposed conditions good linearity has been obtained up to a concentration of the analytes of 10.0 mg L −1 , the limits of detec…
Determination of clenbuterol in urine by azo-dye precolumn derivatization and micellar liquid chromatography
1997
Clenbuterol has been determined in urine by solidphase extraction on a C18 cartridge, diazotization of the eluate with nitrite, coupling of the diazonium ion with 1-(naphthyl)ethylenediamine, and separation of the azo dye formed by HPLC with a C18 column and a micellar mobile phase containing 0.1 M sodium dodecyl sulphate, 12%n-butanol and 0.05 M citrate buffer, pH 3. Recoveries higher than 90% were obtained by mixing the samples with a 20% 0.2 M NaOH before extraction. Limits of detection of 51 and 6.7 ng L−1 were obtained with spectrophotometric and thermal lens spectrometric detection, respectively; respective repeatabilities were 3.1% (5 μg mL−1) and 5.6% (0.16 μg mL−1).
Development of a sensitive method for determining traces of prohibited acrylamide in cosmetic products based on dispersive liquid-liquid microextract…
2020
Abstract According to the European Regulation on cosmetic products, the presence of acrylamide in these consumer products is not allowed due to its mutagenic and potentially carcinogenic effects. Despite this ban, acrylamide might be present in those cosmetic products containing acrylamide-based polymers. However, there is no analytical method for its determination in this type of matrices. Based on this, the development of analytical methods for the determination of acrylamide in cosmetic products is required to guarantee consumer safety. In this work, an analytical method for determining traces of prohibited acrylamide in cosmetic products is presented for the first time. The method is ba…
In situ derivatization for double confirmation of 2C–C in oral fluids by ion mobility spectrometry
2017
Ion mobility spectrometry (IMS) is a powerful tool to carry out quick and sensitive detection of illicit activities and has been employed for the determination of the psychedelic drug 2,5-dimethoxy-4 chlorophenethylamine (2C–C) in oral fluid samples. Saliva samples were extracted with chloroform and analysed by IMS reaching a limit of detection (LOD) of 14 μg L−1. Nevertheless, IMS has a scarce resolution and selectivity of the method can be often compromised by the presence of potential interferents with similar molecular weights and drift times. Thus, a rapid and in situ derivatization with acetone, to form the corresponding imine, has been proposed in the present study to confirm the pre…
Simultaneous quantification of serum phytosterols and cholesterol precursors using a simple gas chromatographic method
2012
Determination of the main phytosterols (Ps, β-sitosterol and campesterol) and cholesterol precursors (desmosterol and lathosterol) in human serum using a simple GC-FID method has been validated. Direct saponification, without lipid extraction, sterols extraction, and further derivatization was applied to samples prior to GC analysis. To evaluate the method, a pool of serum samples from eight healthy women was used. Good linearity (r>0.99) was found in the assay range: β-sitosterol (0.99–17.82 µg/mL), campesterol (0.14–10.8 µg/mL), desmosterol (0.17–2.6 µg/mL), and lathosterol (0.6–5.97 µg/mL). Limits of detection (ng/mL) were: 86 (β-sitosterol), 42 (campesterol), 4 (desmosterol), and 44 (la…
Quantitative determination of moniliformin in vegetable foods and feeds
1984
A suitable and simple method for the quantitative determination of moniliformin in vegetable foods and feeds is described. The mycotoxin was extracted by Soxhlet extraction with methanol from mouldy maize, rice, rye, oats, wheat and barley samples. Moniliformin was determined by thin-layer chromatography (TLC) using N-methylbenzthiazolon-2-hydrazone (MBTH) as a new derivatization reagent for this mycotoxin. The moniliformin derivative was assayed at 518 nm. Quantification could be performed after calibration. A linear relationship between mycotoxin amount and peak area was found from 100 to 400 ng/spot. The detection limit is 75 ng/spot.