Metabolite extraction procedure urine

Jenkins KM, Young MS, Mallet CR, Elian AA (2004) Mixed-mode solid-phase extraction procedures for the determination of MDMA and metabolites in urine using LC-MS, LC-UV, or GC-NPD. J Anal Toxicol 28(l) 50-58... 

Application of LC-MS/MS techniques to the analysis of phthalate ester metabolites in urine have also been developed. For example, Blount et al. (2000b) have developed an assay to quantify the monoester metabolites (including MEHP) of eight phthalate diesters in urine, utilizing HPLC coupled with atmospheric pressure chemical ionization and tandem mass spectrometric (APCI-MS/MS) detection techniques. Urine samples were treated with -glucuronidase to release the free phthalate monoesters followed by a two-step solid phase extraction procedure. After evaporative concentration of the eluant, the analytes in the purified samples are further separated on a phenyl reverse phase HPLC column and quantified by APCI-MS/MS, following careful optizimation of the APCI-MS/MS instrument. The limits of detection for MEHP were determined to be 1.2 ng/ml urine with recovery efficiencies of between 78 and 91%. 

THC and its metabolites can be detected in plasma or urine samples only within a few hours to days after cannabis intake, which was documented by numerous extraction procedures. - At the opposite, hair appears to be an interesting substrate for the investigation of chronic exposure. ... 

Disposition in the Body. Rapidly but incompletely absorbed after oral administration bioavailability about 65%. Up to 90% of an intravenous dose is excreted in the urine, mainly as unchanged drug with up to 14% of the dose as a glucuronide conjugate. 2-Amino-4-chloro-5-sulphamoylanthranilicacid has been reported as a metabolite in several studies, but in other cases it has not been detected and it has been suggested that it is an analytical artefact produced during acid extraction procedures. In normal subjects, about 6 to 18% of a dose is eliminated in the faeces after intravenous administration this may be increased to about 60% in renal failure. 

Beckett and Triggs were interested in the determination of nicotine and its main metabolite cotinine in urine. An acidified urine was extracted with diethyl ether to remove impurities, the urine was made alkaline with sodium hydroxide and the nicotine extracted with diethyl ether. Cotinine was extracted from urine with methylene chloride after basification of the sample with ammonia. On concentration of the solution, the gas chromatography was carried out on a packed column treated with KOH using Carbowax 20 M as stationary phase. A relative recovery of 95-100 % for the two alkaloids was obtained with respect to their internal standard, chlorophentermine for nicotine and lignocaine for cotinine, which were added to the urine at the start of the assay procedure. Typical chromatograms are given in Figure 4. 

Feng S, ElSohly MA, Salamone S, Salem MY (2000) Simultaneous analysis of delta-9-THC and its major metabolites in urine, plasma, and meconium by GC-MS using an immunoaffinity extraction procedure. J Anal Toxicol 24 395-402... 

Some abuse drugs have been extracted from urine by SFE [viz. cocaine and its metabolites (134) and amphetamine and methamphetamine (135). In the first instance, the levels measured using SFE showed analyte recovery better than 70% for cocaine, better than 40% for benzoylecgonine, and better than 85% for ecgonine methyl ester from whole blood and urine. The limits of detection and quantitation were 1 and 10 ng, respectively, based on a 200-pL sample. Regarding amphetamine (AP) and methamphetamine (MA), an in situ SFE and chemical derivatization procedure followed by GC-isotope dilution mass spectrometry in urine was described. The mean recoveries achieved were 95% (RSD = 3.8%) for AP and 89% (RSD = 4%) for MA. The calibration graphs were linear within 100-500,000 ng/mL, varying the limits of detection and quantitation from 19 to 50 and from 21 to 100 ng/mL, respectively. 

Urine. Urine samples collected from cows 821 and 59 in the 0-12 hour period after the administration of a 30 mg dose (injection 2) were utilized in the isolation and identification of metabolites. The isolation procedure involved ethyl acetate extraction of urine followed by solid phase extraction of the ethyl acetate extract on C-18 Bond Elut cartridges. The extract was derivatized into methyl esters with diazomethane and subjected to silica and alumina chromatography for further cleanup prior to analysis. The detailed procedure is described in flow diagram 1. 

King et al. (1992) described a unique combination extraction/sample application procedure in which a disk was placed into a hole in a TLC sheet to determine the presence of cannabinoid (THC) metabolite in human urine. Using this procedure, hydrolyzed urine samples were aspirated directly through a small. 

Beyer J, Peters F, Mamer HH(2005) Screening procedure for detection of stimulant laxatives and/or their metabolites in human urine using gas chromatography-mass spectrometry after enzymatic cleavage of conjugates and extractive methylation. Ther Drug Monit 27 151-157... 

THC-COOH, as the main metabolite of THC in urine, can be detected for many days after the last consumption of cannabis products. The THC-COOH concentration depends not only on the amount of drugs used, but also on the THC-content of the consumed cannabis product. Measurements with the method described above have shown that none of the commonly prescribed or OTC drugs interfered with the quantification of THC-carbonic acid in urine samples. This is due to the effective Extrelut extraction procedure. In addition. 

---