Determination of polyol profiles in human urine by capillary gas chromatography

A new rapid capillary gas chromatographic method is described for the profile analysis of urinary polyols as their trifluoroacetyl derivatives. Ten urinary polyols: erythritol, threitol, fucitol, ribitol, arabinitol, xylitol, mannitol, glucitol, galactitol and myo-inositol were completely determined for the first time. Iditol was newly found in normal urine. Urinary polyols were verified by gas chromatography/mass spectrometry.     

Determination of pholcodine and its metabolites in urine by capillary gas chromatography

A sensitive and selective method for the determination of pholcodine and its metabolites in urine using capillary gas chromatography with nitrogen detection is described. The procedure includes enzymatic hydrolysis of urine by beta-glucuronidase and sample pretreatment on C2 solid-phase extraction columns. Validation of the method showed good sensitivity, precision and reproducibility. The method was useful for the study of pholcodine metabolism in man. Pholcodine was found to conjugate with glucuronic acid. Morphine was identified as a metabolite and another unidentified metabolite was also detected.     

Determination of polyamines in urine of normal human and cancer patients by capillary gas chromatography

A capillary gas chromatographic method is described for the determination of polyamines (putrescine, spermidine and spermine) in the urine of normal human and cancer patients. Morning urine after acid hydrolysis is cleaned up on a silica gel column and derivatized with trifluoroacetic-anhydride. Creatinine in human urine is used as internal standard. Recoveries of polyamines are 96.7% putrescine, 102.6% spermidine (Spd), and 98.7% spermine. SD of the method for Spd is 1.949 +/- 0.041 (micrograms/mg creatinine, mean +/- SD, n = 5). The results show that the mean level of polyamines in cancer patients urine is much higher than that in normal human urine. The mean of total polyamines in the normal human and the cancer patients is 2.01 and 44.74, respectively (g/mg creatinine).     

Determination of urinary succinylacetone by capillary gas chromatography

The average analytical recovery of succinylacetone added to urine and separated by capillary gas chromatography was 69% for solvent extraction and 72% for anion exchange separation. Treating succinylacetone with hydroxylamine hydrochloride at a pH of less than 5 caused formation of a derivative separated by capillary gas chromatography into two isomers: 3-methyl-5- isoxazole propionate and 5-methyl-3- isoxazole propionate as their trimethylsilyl derivatives (molecular weight 227). In a pH greater than or equal to 5, succinylacetone dioxime was formed and separated into 3 isomers as their trimethylsilyl derivatives (molecular weight 404). Succinylacetone dioxime was converted to 3(5)-methyl-(3)5- isoxazole propionate whenever the pH of the solution was dropped to less than 5. Mass spectra of both derivatives are shown. This study demonstrates that capillary gas chromatography is suitable for use in urinary succinylacetone determination.     

毛细管气相色谱法测定邻氨基苯甲酸甲酯的含量

应用气相色谱法测定邻氨基苯甲酸甲酯的含量.采用氢火焰离子化检测器,色谱柱为OV1701毛细管柱,柱温200℃,检测器温度260℃,氮气做载气,流速1.2 mL/min.实验表明在上述色谱操作条件下,邻氨基苯甲酸甲酯的浓度在5.0~40.0 g/L范围内具有良好的线性关系,平均回收率为99.49%.该方法简便、准确、重复性好,可用于工业邻氨基苯甲酸甲酯的含量测定.     

Determination of amino acids in urine by gas chromatography

This report describes a convenient means of reducing the complex matrix which is responsible for interference during gas chromatographic determination of amino acids in urine. The pre-chromatographic clean-up employs the principle of solid phase extraction using bonded silica incorporating cation exchange groups. This approach avoids the detrimental effects on amino acid recoveries associated with resin-based cation exchangers. In spite of significant reduction in the complexity of chromatograms, only the high efficiency and resolving power offered by the analytical capillary column (e. g. fused silica open tubular, FSOT) is sufficient for quantitative and analysis of amino acids in urine. Reproducibility data from the complete procedure are determined, coefficients of variation (CV) for most amino acids being better than 5% with a mean recovery of 96%.     

Determination of fosfomycin in human urine by capillary gas chromatography: Application to clinical pharmacokinetic studies

Summary A capillary gas chromatographic method for the determination of fosfomycin in human urine is described. After dilution of the sample and derivatization, analysis was on a HP-1 capillary column and a flame ionization detector was used to determine the bistrimethylsilyl derivative of fosfomycin. Response was linear in the range 50–5000 g mL^–1. The detection limit was about 10 g mL^–1. The within and between day coefficients of variation did not exceed 6%. The method was applied to the determination of fosfomycin in urine samples collected during clinical pharmacokinetic studies.     

Determination of carphedon in human urine by solid-phase microextraction using capillary gas chromatography with nitrogen-phosphorus detection

Carphedon is a phenyl derivative of nootropil and is effective in increasing physical endurance and cold resistance, and is used for amnesia treatment. Carphedon was extracted from human urine samples by solid-phase microextraction with a 65 microns carbowax-divinylbenzene-coated fiber. This analysis was performed by using capillary gas chromatography with nitrogen-phosphorus detection and optimized at pH 9.6, 30% NaCl, immersion time 10 min and desorption in the GC injector at 250 degrees C for 3 min. The regression equation for carphedon showed good linearity in the range from 0.1 to 10 micrograms ml-1 for human urine samples. The limit of detection was 0.01 microgram ml-1. The developed method is more sensitive and simpler in sample preparation than liquid-liquid extraction and can be applied to doping analysis for stimulants.     

Determination of amino acid enantiomers in orange juices by chiral phase capillary gas chromatography

Summary The configurations of free amino acids (AAs) in orange juice beverages (commercial products of satisfactory and unsatisfactory quality), an orange juice concentrate (bulk product suspected of being adulterated), and in an orange juice that has been contaminated by addition ofLactobacillus plantarum as a model for microbial spoilage, were determined, after derivatization, by means of gas-liquid chromatography (GC) using fused-silica capillary columns coated with Chirasil-L-Val or Chirasil-D-Val as stationary phases. AAs were isolated from juices by treatment with Dowex WX8 ion-exchanger and were investigated, by GC, as theirN(O)-pentafluoropropionylorN(O)-trifluoroacetyl 1-propyl esters. It was found that the high quality orange juice beverage contained L-AAs exclusively whereas this juice, after fermentation withLactobacillus, contained free D-Ala (32.7%), D-Val (62.3%), D-Phe (20.0%), D-Glu (24.3%), D-Ser (2.6%), D-Asp (0.8%), and significant amounts of D-Pro [% D=100 D/(D+L)]. D-Ala (8.8%) and D-Ser (4.2%) were found in a sensory and analytically unsatisfactory orange juice beverage, whilst D-Ala (27.5%) and D-Ser (14.3%) were detected in the orange juice concentrate suspected of being adulterated.Although capillary GC on chiral stationary phases is regarded as being highly suitable for the determination of AA enantiomers in fruit juice beverages, detection of D-AAs is currently not considered as conclusive proof of fruit juice adulteration caused by addition of AA racemates since a non-microbial origin of D-AAs in the respective juice, or an original occurrence of D-AAs, in either the free, substituted, or peptide-bonded form in the fruits, cannot be excluded with certainty.Presented in part at the Deutscher Lebensmittelchemikertag, Sept. 18–21, 1990, Frankfurt and at the 14. Jahrestagung Deutscher Lebensmitteltechnologen, Nov. 15–17, 1990, Düsseldorf.     

Determination of methyl ethyl ketone and its metabolites in urine using capillary gas chromatography

A method is described for the determination of the concentration of methyl ethyl ketone and its metabolites: 2-butanol, 3-hydroxy-2-butanone and the meso- and d,l-isomers of 2,3-butanediol in urine. The analytes were isolated from urine by solid-phase extraction and analysed by capillary gas chromatography. The recovery rates were 50-70% for the 2,3-butanediol isomers and 88-96% for the other analytes. The precision of the method ranged from 5 to 12% (S.D.%). The detection limit was 1.0 and 1.4 mg/l for meso- and d,l-2,3-butanediol, respectively, and ranged from 0.1 to 0.15 mg/l for the other analytes.     

Determination of clozapine in human serum by capillary gas chromatography

A gas chromatographic method using a fused-silica wide-bore capillary column and a nitrogen-specific detector for the determination of the antipsychotic agent clozapine in human serum is described. This method was found to be suitable for the determination of serum levels down to 1-2 ng/ml. The sensitivity, precision and accuracy of this method are adequate for studies on pharmacokinetics and bioavailability.