Determination of zeranol and beta-zearalanol in calf urine by immunoaffinity extraction and gas chromatography-mass spectrometry after repeated administration of zeranol

A method for the determination of zeranol and its metabolite beta-zearalanol in bovine urine is described. It has been applied to samples from calves given multiple subcutaneous doses of zeranol. Samples were extracted with immunoaffinity columns containing antibodies raised against zeranol and were analysed by gas chromatography-mass spectrometry. The immunoaffinity columns were prepared by coupling immunoglobulin G fractions obtained from rabbit antisera with a Sepharose matrix. The immunizing agent was carboxybutylzeranol coupled to bovine serum albumin. Gas chromatography-mass spectrometry was performed in the negative-ion chemical ionization mode, after derivatization of the compounds to their pentafluorobenzyl ethers, and allowed detection of analytes with a sensitivity of 0.01 ppb in spiked urine. The derivatization method and the gas chromatographic determination were also applied to the similar compounds zearalanone, zearalenone and beta-zearalenol. A synthesis of dideuterated zeranol and beta-zearalanol by isotopic exchange is described. These deuterated analogues had an isotopic purity of more than 99% and were used for quantitation of zeranol and beta-zearalanol by isotope dilution mass spectrometry. The recoveries of zeranol and beta-zearalanol, using the immunoaffinity columns, were determined after extraction from spiked urine and were 84 and 64%, respectively. The urines of treated calves were collected for several days after treatments and were analysed after hydrolysis with beta-glucuronidase and arylsulphatase. The samples showed variable but generally decreasing concentrations of zeranol and beta-zearalanol. The levels of beta-zearalanol ranged from less than 0.01 to 98 ppb and were 1.2-3.2 times higher than those of zeranol.     

利尿剂的胶束色谱分析

用十二烷基硫酸钠（SDS）胶束溶液作为流动相，建立了11种利尿剂的胶束色谱系统分析方法；研究了SDS浓度、流动相的pH、有机改性剂及温度对色谱保留行为的影响，优化了色谱条件，并且不经化学处理直接进样测定了人尿中的烯睾丙内酯；该法适用于兴奋剂中利尿剂的常规分析。     

Determination of pyrimethamine in animal tissue and egg by liquid chromatography with fluorescence detection

A sensitive and selective liquid chromatographic (LC) assay was developed to determine the concentration of pyrimethamine in animal tissue and egg by fluorescent derivative. Animal samples were extracted with acetonitrile, centrifuged, and purified by hexane. Fluorescent derivatization was performed by reacting pyrimethamine with chloroacetaldehyde and subjected to LC with fluorescence detection (excitation wavelength 300 nm, emission wavelength 420 nm). The limit of detection was 10 ng/g (10 ppb) and the standard calibration curve was linear in the range of 1-100 ppb (0.01-1 ng/10 microL). Recoveries from samples fortified at levels of 0.1 and 1 ppm (microg/g) were 61.0-77.4 and 65.5-81.2%, respectively. The method was applied to the monitoring of marketed samples. Pyrimethamine was not determined in any of the 70 samples: 20 swine muscle; 20 chicken muscle; 10 chicken liver; and 20 egg.     

Caffeine Determination in Human Saliva and Urine by TLC and Ultraviolet Absorption Densitometry

A quantitative method using thin-layer chromatography (TLC) plates with concentrating zone and ultraviolet absorption densitometry is described for caffeine (CAF) determination in human saliva and urine. The applicability of the CAF method was tested for saliva and urine from male individuals. The changes of salivary CAF, urinary CAF concentration and of urinary CAF excretion correspond with results of previous investigations using gas chromatography, high performance liquid chromatography, radioimmunoassay or enzyme immunoassay methods. In summary, the thin-layer chromatography/densitometry method here described is easy to perform, reproducible and accurate. Thus, it is suitable for routine analysis of CAF in human saliva or urine, being an effective alternative to other, more expensive and more time-consuming chromatographic or immunological methods.     

High-performance liquid chromatographic separation of cadralazine from its potential metabolites and degradation products. Quantitation of the drug in human plasma and urine

The chromatographic behaviour of cadralazine and its potential metabolites and degradation products with respect to pH, buffer molarity and composition of eluent is described. A selective method with an adequate sensitivity for the determination of the drug in human plasma and urine is also reported. The method includes extraction of biological fluids with chloroform and the analysis of extracts on a reversed-phase column with isocratic elution and detection at 254 nm. The method has been applied to the analysis of plasma and urine of a patient administered a single oral dose of 30 mg of cadralazine.     

Reversed-phase liquid chromatographic separation and simultaneous fluorimetric detection of polyamines and their monoacetyl derivatives in human and animal urine, serum and tissue samples: an improved, rapid and sensitive method for routine application

A highly sensitive and precise method for the determination of the polyamines putrescine, cadaverine, spermidine and spermine and all their monoacetyl derivatives in a single analysis in human and animal urine, serum and tissue samples is described. For polyamine separation, an ion-pairing reversed-phase high-performance liquid chromatographic (HPLC) method is used, followed by post-column derivatization with o-phthalaldehyde and consecutive fluorescence detection. Urine and serum samples are purified with a Bond Elut silica cartridge. The detection limit for polyamines is 0.5-1.0 pmol and excellent linearity is achieved in the range from 3 pmol up to more than 10 nmol. The influence of some modifications of different analytical steps such as the temperature of the HPLC column and the derivatization reaction coil and the o-phthalaldehyde flow-rate is described. Quality control data and measurements of the reproducibility of the method are presented. In order to establish a rapid analytical method for easy routine use, all steps for preparation and quantitative analysis are minimized. This method was applied to the determination of total polyamines in human urine and serum hydrolysate and of free and acetylated polyamines in human urine and pancreatic tissue of the rat. Values for normal polyamine concentrations in the urine and serum of fifteen male and fifteen female healthy volunteers and in the pancreas of ten normal rats are presented.     

High-performance liquid chromatographic determination of lansoprazole and its metabolites in human serum and urine.

A simple and sensitive high-performance liquid chromatographic method with ultraviolet detection is described for the simultaneous determination of lansoprazole and its metabolites in human serum and urine. The analytes in serum or urine were extracted with diethyl ether-dichloromethane (7:3, v/v) followed by evaporation, dissolution and injection into a reversed-phase column. The recoveries of authentic analytes added to serum at 0.05-2 micrograms/ml or to urine at 1-20 micrograms/ml were greater than 88%, with the coefficients of variation less than 7.1%. The minimum determinable concentrations of all analytes were 5 ng/ml in serum and 50 ng/ml in urine. The method was successfully applied to a pharmacokinetic study of lansoprazole in human.     

High-performance liquid chromatographic determination of taurine in biological fluids by post-column fluorescence reaction with thiamine.

A high-performance liquid chromatographic method is described for the selective determination of taurine in biological fluids by post-column fluorescence reaction. Taurine was separated on an adsorption-distribution type Shodex Ionpac KC-811 column. Then it was converted with hypochlorite into the corresponding N-chloramine, which was allowed to react with thiamine to give fluorescent thiochrome. As little as 6 ng per injection of taurine could be determined. The average recoveries of spiked taurine in serum and urine were 99.5 +/- 2.7 and 101.8 +/- 2.9%, respectively. The method could be applied to the assay of taurine in human serum and urine with simple pretreatment.     

A new method for the quantitation of aflatoxin M1 in urine by high performance liquid chromatography and its application to the etiologic study of hepatoma

A high performance liquid chromatographic (HPLC) method for the analysis of aflatoxin M1 (AFM1) in urine is described. Urine samples were treated with saturated lead acetate and AFM1 was extracted with chloroform. After washing with water to remove impurities the compound was derivatized with trifluoroacetic acid and the AFM1 derivative was analyzed quantitatively by HPLC. The sample pretreatment is simple and more selective. A good line correlation between AFM1 peak height and its concentration was obtained when AFM1 content was in the range of 50-400 pg. The ratio of recovery was 87.42%. Sensitivity is 0.01 ppb. The method is applicable to trace analysis. Results in urine of residents who live in the high/low liver cancer incidence area in Fushui county were the same as that of previous epidemiological investigation.     

Activation analysis of mercury in urine samples of electrolysis cell workers

The activation method of determination of trace amounts of Hg in human urine has been studied by introducing a simple amalgam deposition method. Human urine samples were obtained from the alkali chloride, electrolysis plant equipped with Hg cells. The capacity of Cu powder for Hg quantity, the pH conditions, and the shaking time were described. The results showed that the Hg contents in workers' urine samples varied from 33 ppb to 60 ppb depending on working conditions.     

Automated solid-phase extraction for concentration and clean-up of female steroid hormones prior to liquid chromatography-electrospray ionization-tandem mass spectrometry: an approach to lipidomics

A method for determination of free and glucuronide-conjugated female steroid hormones in urine at the pgmL(-1) level is here presented. For this purpose, a dual approach with or without beta-glucuronidase hydrolysis has been developed to succeed in this analysis. The target analytes were two progestogens - progesterone and pregnenolone - and three endogenous estrogens - estradiol, estriol and estrone. Separation and detection were carried out by liquid chromatography electrospray ionization and tandem mass spectrometry (LC-ESI-MS-MS) with a triple quadrupole (qQq) mass detector. The determination step was optimized by multiple reaction monitoring for highly selective identification and sensitive quantification of female hormones in a complex sample such as human urine. As these compounds are present in urine at very low concentration (ngmL(-1) level), a preconcentration and clean-up step by solid-phase extraction was automatically carried out prior to the chromatographic step in order to improve the sensitivity of the method. This sample pretreatment was performed using a lab-on-valve (LOV) manifold which provided preconcentration factors ranging from 59.1 to 72.3 for 10mL urine. The detection and quantification limits were in the ranges 1.8-18pg and 6-61pg on-column, respectively, with precision values from 1.93 to 10.99%, expressed as relative standard deviation. These results enable to conclude the suitability of the LOV-LC-qQq approach for determination of the lipidomic profiling of the main female steroid hormones in a difficult matrix as human urine. The method can be potentially applied to the clinical and other metabolomic areas.     

Liquid chromatographic determination of polyamines in human urine based on intramolecular excimer-forming fluorescence derivatization using 4-(1-pyrene)butanoyl chloride

A liquid chromatographic method for highly sensitive and selective fluorometric determination of polyamines (putrescine, cadaverine, spermidine and spermine) in human urine is described. This method is based on an intramolecular excimer-forming fluorescence derivatization with a pyrene reagent, 4-(1-pyrene)butanoyl chloride (PBC), followed by reversed-phase liquid chromatography. The method offers higher sensitivity for determination of spermidine and spermine than previously reported method utilizing 4-(1-pyrene)butyric acid N-hydroxysuccinimide ester as a derivatization reagent. Samples containing free polyamines in diluted human urine were directly derivatized with PBC and separated on an octyl column. The derivatives were detected at excitation 345 and emission 475 nm wavelengths. For determination of total polyamine content, the conjugated polyamines were first hydrolyzed in 4 M HCl. The detection limits (signal-to-noise ratio = 3) for polyamines in urine were 1.1-3.4 pmol/mL. At optimized derivatization and chromatographic conditions, interferences such as biogenic monoamines gave no peaks or the peaks did not interfere with the peaks of polyamine derivatives. In conclusion, the present derivatization method allows direct determination of polyamines in human urine samples without the need for sample clean-up procedures.     

Direct determination of chromium(III) and chromium(VI) with ion chromatography using direct current plasma emission as element-selective detector

A method is described that utilizes direct current plasma atomic emission spectrometry as an element-selective method of detection for ion chromatographic determination of chromium(III) and chromium(VI) species. The eluting chromium-containing species are detected on the basis of the atomic emission of chromium without any species conversion. Both anion and cation separator columns give similar results when used with varying sample matrices. By employing an on-column preconcentration procedure, the detectable concentrations of the chromium species are reduced to less than 1.0 ppb. This method is applied to the determination of chromium species in human serum, natural water, and industrial process stream samples.     

Determination of vigabatrin in human plasma and urine by high-performance liquid chromatography with UV-Vis detection

A simple and reliable high-performance liquid chromatographic (HPLC) method with UV-Vis detection has been developed and validated for the determination of vigabatrin (VG) in human plasma and urine. The samples were pre-column derivatizated with 1,2-naphthoquinone-4-sulphonic acid sodium salt (NQS). A good chromatographic separation was achieved on a C18 column with a mobile phase consisting of acetonitrile and 10 mM orthophosphoric acid (pH 2.5) gradient elution. Tranexamic acid was used as an internal standard (I.S.). The method was linear over the concentration range of 0.8-30.0 microg/ml for both samples. The method is precise (relative standard deviation (R.S.D.) <9.13%) and accurate (relative mean error (RME) <-8.75%); analytical recoveries were 81.07% for plasma and 83.05% for urine. The assay was applied to pharmacokinetic study in a healthy volunteer after a single oral administration of 1 g of vigabatrin.     

Determination of lasalocid with sensitized terbium(III) luminescence detection

The luminescence of the lasalocid-terbium(III) system in the presence of Triton X-100 and trioctylphosphine oxide has been studied by obtaining kinetic and equilibrium measurements and using the stopped-flow mixing technique. The initial rate and luminescence signal of this system are directly proportional to the lasalocid concentration, which allows one to develop very simple, fast, automatic methods for the determination of this analyte. Kinetic and equilibrium data can be obtained in only 0.1 and 10 s, respectively. The calibration graphs were linear over the range 0.004-5.0 mug ml(-1) (kinetic method) and 0.01-5.0 mug ml(-1) (equilibrium method) and the detection limits achieved were 1 and 3 ng ml(-1), respectively, equivalent to 2 and 6 ng g(-1) lasalocid in a chicken liver sample, which are similar to those afforded by the chromatographic methods described for this determination. The relative standard deviation of both methods was close to 2%. The analytical recoveries obtained by applying the kinetic and equilibrium methods to drinking water, poultry feed and chicken liver samples ranged from 95.6 to 102.1% and from 95.9 to 104.9%, respectively.     

Determination of cibenzoline in plasma and urine by high-performance liquid chromatography

A rapid, sensitive and selective high-performance liquid chromatographic (HPLC) assay was developed for the determination of cibenzoline (CipralanTM) in human plasma and urine. The assay involves the extraction of the compound into benzene from plasma or urine buffered to pH 11 and HPLC analysis of the residue dissolved in acetonitrile-phosphate buffer (0.015 mol/l, pH 6.0) (80:20). A 10-microns ion-exchange (sulfonate) column was used with acetonitrile-phosphate buffer (0.015 mol/l, pH 6.0) (80:20) as the mobile phase. UV detection at 214 nm was used for quantitation with the di-p-methyl analogue of cibenzoline as the internal standard. The recovery of cibenzoline in the assay ranged from 60 to 70% and was validated in human plasma and urine in the concentration range of 10-1000 ng/ml and 50-5000 ng/ml, respectively. A normal-phase HPLC assay was developed for the determination of the imidazole metabolite of cibenzoline. The assays were applied to the determination of plasma and urine concentrations of cibenzoline and trace amounts of its imidazole metabolite following oral administration of cibenzoline succinate to two human subjects.     

Determination of urea using high-performance liquid chromatography with fluorescence detection after automated derivatisation with xanthydrol

A high-performance liquid chromatography (HPLC) method for the determination of urea that incorporates automated derivatisation with xanthydrol (9H-xanthen-9-ol) is described. Unlike the classic xanthydrol approach for the determination of urea, which involves the precipitation of dixanthylurea (N,N'-di-9H-xanthen-9-ylurea), the derivatisation procedure employed in this method produces N-9H-xanthen-9-ylurea, which remains in solution and can be quantified using fluorescence detection (lambda(ex)=213 nm; lambda(em)=308 nm) after chromatographic separation from interferences. The limit of detection for urea was 5 x 10(-8) M (0.003 mg L(-1)). This method was applied to the determination of urea in human and animal urine and in wine.     

Determination of vanadium in biological tissue by anion exchange chromatography and neutron activation analysis

A method is described for determination of vanadium in biological tissues. This method consists of a wet digestion of the tissue with nitric acid followed by anion exchange chromatography, neutron irradiation, and radioassay. The chromatographic separation will allow the decontamination of vanadium from radioactivatable sodium and chlorine which are present in large quantities in biological tissues. The validity of the method is evaluated by employing NBS-SRM 157 and 157a Bovine Liver employing the method of standard additions. The method is successfully applied to human, cow and rat liver specimens. The detection limit of the method is one ppb.     

High-performance liquid chromatography-electrochemical detection of 3-methylhistidine in human urine.

A reversed-phase high-performance liquid chromatographic method is described for the determination of 3-methylhistidine content in human urine using pre-column derivatization with phenylisothiocyanate, isocratic elution with 15 mM sodium acetate-acetonitrile (92:8, v/v) and electrochemical detection. The limit of quantitation was 0.1 pmol. The method has been applied in routine analyses of 3-methylhistidine in both clinical and research work.     

Determination of amphetamines in human urine by liquid chromatography with fluorimetric detection using a solid-phase extraction procedure

A precise and feasible HPLC method has been developed for the analysis of amphetamine (AMPH), methamphetamine (MAMPH) and methylenedioxymethamphetamine (MDMA, ecstasy) in human urine. A chromatographic run on a C8 Genesis (150 mm x 4.6 mm, 5 microm) column maintained at 30 degrees C lasts about 17 min, using a mobile phase composed of ACN (12%) and a pH 2.5 phosphate buffer (88%) containing 0.3% triethylamine. Mirtazapine was used as the internal standard. Good linearity was found in the 100-2000 ng/mL concentration range for AMPH and MAMPH and in the 12-2000 ng/mL concentration range for MDMA. The pretreatment of urine samples was carried out by means of a careful SPE procedure on C2 cartridges. The extraction yields were very satisfactory for all analytes, with average values greater than 97%. The leading conditions allowed the determination of AMPH, MAMPH and MDMA with satisfactory precision and accuracy. The method has been successfully applied to the determination of the analytes in urine of AMPH users.