A new method for optical control of manipulative-type orthoses for high-level quadriplegics

The sulfate and phosphate conjugates of 19-nortestosterone (17beta-hydroxy-estr-4-ene-3-one) and ent-19-nortestosterone (ent-17beta-hydroxy-estr-4-ene-3-one) have been synthesized. The sodium salts of the conjugates were i.v. infused to 2 women. On days 1--4 following application, the 19-nortestosterone and 17-ketosteroid excretion in urine as well as the 19-nortestosterone conjugation have been estimated. The 19-nortestosterone enantiomers were excreted in nearly the same amounts. In comparison to testosterone, the excretion of unchanged steroid (20--50%) is significantly higher. The sulfate conjugates of the enantiomers are not hydrolyzed in vivo, whereas the phosphate conjugates are completely splitted. Hydrolysis of ent-nortestosterone phosphate takes place obviously more slowly. Urinary 17-ketosteroids are significantly increased only following infusion of 19-nortestosterone phosphate.     

Multiresidue method for the chromatographic determination of triazine herbicides and their metabolites in raw agricultural products

A method is described for the determination of 19 triazine herbicides and 4 metabolites in 6 agricultural products that represent diverse matrixes. In addition, a modification of this method to determine the more water-soluble metabolite, desethyldesisopropylatrazine, is described. In both these procedures, residues are extracted with methanol, and the product coextractives are removed using solvent partition and cation-exchange solid-phase extraction chromatography. A nitrogen phosphorus detector and DB-17 megabore column are used for the temperature-programmed chromatographic determination of samples fortified at 0.02-1.0 ppm levels. Average recoveries ranged from 81.1 to 106.2% for the parent herbicides and from 59.6 to 87.5% for the metabolites on all crops. An average recovery of 101.1% was obtained for desethyldesisopropylatrazine.     

Determination of organochlorine pesticide and polychlorinated biphenyl residues in fatty fish by tandem solid-phase extraction cleanup

A rapid, multiresidue solid-phase extraction (SPE) technique for determination of organochlorine pesticide and polychlorinated biphenyl (PCB) residues in nonfatty fish was modified for use with fatty fish. In the modified procedures, samples are extracted with acetonitrile, and the extract is cleaned up with both C18 and Florisil SPE columns. Residues are determined by gas chromatography with electron capture detection. The original method was modified for use with fatty fish by reducing the amount of tissue extracted and by using an improved Florisil SPE cleanup. Recovery data are presented for 24 fortified organochlorine pesticide residues (0.12 ppm) and 3 fortified PCB residues (0.80 ppm) from flounder, bluefish, and shad samples, which contained 0.8, 5.4, and 22.6% fat, respectively. For the 3 types of fish, recoveries of 23 of 24 fortified organochlorine pesticide residues ranged from 55 to 129%, and recoveries of 3 fortified PCB residues ranged from 55 to 104%. There were no significant differences in recovery based on fish species and/or fat content for the majority of residues studied. This SPE method and the official AOAC method yielded comparable results for fish containing incurred organochlorine residues.     

Methods for the determination of organochlorine pesticide residues in human serum

The effectiveness of solid-phase extraction with Florisil for the determination of 12 organochlorine pesticide residues from human serum was examined. Recoveries greater than 84% and coefficients of variation better than 19% were obtained. Others methods, such as column partition and matrix solid-phase dispersion, were compared. The better method provides quantification limits ranging from 1.08 microg/l for gamma-HCH and 37.5 microg/l for p,p'-DDT when capillary gas-liquid chromatography with electron-capture detection is used for the final determination.     

PMBP-苯溶剂萃取-ICP-AES快速测定化探样品中15种稀土元素

建立了在p H=5.5的酸度下,使用PMBP-苯溶剂定量萃取化探样品中15种稀土元素,然后用甲酸-8-羟基喹啉溶液反萃取稀土元素,分离后ICP-AES同时测定的新方法。成功解决了盐酸、硝酸、氢氟酸、高氯酸消解后ICP-AES直接测定稀土元素基体成分复杂,质谱干扰严重,方法检出限高等问题,试样用过氧化钠-氢氧化钾熔融后,水提取,过滤,滤渣酸溶,经过沉淀和溶剂萃取等分离富集,对稀土组份进行全分析。方法快速、准确、易操作,其检出限为0.003~0.068 ug/m L,精密度RSD2%。     

微波消解-电感耦合等离子体原子发射光谱法测定二氧化钛中微量杂质元素

采用HF-HNO3混合酸作为消解试剂,建立了微波消解电感耦合等离子体原子发射光谱法(ICP-AES)测定二氧化钛中Si,Fe,Al,Ca,Cu,As,Pb等19种共存杂质元素的新方法。考察了微波消解参数、基体效应、共存元素干扰,分析谱线选择及仪器工作条件等参数,结果表明,基体钛和共存元素不干扰测定,因此在绘制工作曲线时不需要进行基体匹配。方法检出限较低,用于测定二氧化钛各杂质元素平均回收率为96%~106%,相对标准偏差(RSD)小于7.7%,与其他分析方法相对照,测定结果较为吻合。     

Gas-liquid chromatographic determination of alachlor (2-chloro-2', 6'-diethyl-N-(methoxymethyl)-acetanilide) herbicide residues in corn and soybeans

A method has been developed for the extraction and determination of alachlor (2-chloro-2',6'-diethyl-N- (methoxymethyl)-acetanilide) residues in green corn and soybeans. Residues are extracted with acetonitrile and cleaned up on a Florisil column. The methylene chloride extract is sufficiently clean for electron capture gas-liquid chromatographic analysis and for verification by thin layer chromatography. Average recoveries of spiked samples (0.2 ppm) were 69 and 82% for corn and soybeans, respectively. This procedure could be useful for the detection of the parent compound in these crops soon after field application, but it does not detect metabolites.     

微波消解-萃取—ICP-MS法测定高纯金中杂质元素

采用国家标准方法ICP-MS法测定高纯金中的杂质元素时,利用传统湿法消解样品后,大量金基体对杂质元素测定产生干扰和抑制作用,影响测定结果的准确度。实验建立微波消解-萃取—ICP-MS法测定高纯金中杂质元素的方法,并对微波消解-萃取条件进行优化,提高金溶解率及金萃取率,消除金基体对杂质元素测定的干扰。该方法可同时测定40种杂质元素,检出限为0.01~0.29μg/g,测定结果相对标准偏差(n=6)为1.29%~4.18%,加入标准物质回收率为86.94%~115.55%,准确度和精密度良好。     

Amino acid analysis by gas-liquid chromatography of N-heptafluorobutyryl isobutyl esters. Complete resolution using a support-coated open-tubular capillary column

Amino acids have been separated by gas-liquid chromatography as their N-heptafluorobutyryl isobutyl esters. Complete resolution of derivatives of all the common amino acids has been achieved using a high-performance support-coated open-tubular capillary column. The analysis time was 30 min. Modifications to the derivatization procedure of MacKenzie and Tenaschuk have been introduced. Acylation by heating at 150 degrees was shown to be destructive; 110 degrees has been selected for routine preparation. To obtain a volatile histidine derivative it has been found necessary to add an antioxidant and to heat samples with ethoxyformic anhydride prior to injection. Amino acid analysis of beta-lactoglobulin after 6 N HCl digestion yielded results in good agreement with those obtained by the conventional ion-exchange method. The method has also been successfully applied to estimation of the different caseins in whole casein and in purified fractions by amino acid analysis of residues liberated by carboxy-peptidase digestion.     

Extraction of incurred sulphamethazine in swine tissue by microwave assisted extraction and quantification without clean up by high performance liquid chromatography following derivatization with dimethylaminobenzaldehyde

A rapid and reliable method using microwave energy is described for the extraction of spiked and incurred (freeze-dried and fresh) sulphamethazine residues from swine tissues/organs (muscle, liver and kidney). Incurred tissues were obtained from an abattoir and freeze-dried pig tissue reference materials were produced as part of a reference material study for the Community Bureau of References, European Communities. The extraction was achieved by irradiating the sample in methanol for 25 s in a household microwave oven, commonly referred to as microwave-assisted extraction (MAE). The extracts were analysed without clean-up by high performance liquid chromatography (HPLC) using a C18 column and detected at 450 nm after derivatization with 4-dimethylaminobenzaldehyde (DMABA) in a heated rector at 40 degrees C. The limit of quantitation was 2.5 micrograms kg-1 of wet tissues. A comparison of MAE with an homogenization technique indicated that MAE worked extremely well for freeze-dried samples, while it showed significant variation for wet tissues. No sulphamethazine was detected in retail pork meat and liver samples when analysed by the MAE technique.     

Partially glucose-capped oligosaccharides are found on the hemoglobins of the deep-sea tube worm Riftia pachyptila

We report here the structural determination of N-linked oligosaccharides found on extracellular hemoglobins of the hydrothermal vent tube worm Riftia pachyptila. Structures were elucidated by a combination of electrospray ionization tandem mass spectrometry, matrix-assisted laser desorption/ionization mass spectrometry, normal-phase high performance liquid chromatography, and exoglycosidase digestion. The sugar chains were found to consist mainly of high-mannose-type glycans with some structures partially capped by one or two terminal glucose residues. The present study represents the first report of the occurrence of glucose capping of N-linked carbohydrates in a secreted glycoprotein of a metazoan. Previously, glucose capping has only been described for a membrane-bound surface glycoprotein from the unicellular parasite Leishmania mexicana amazonensis.     

A new method for the determination of steroidal hormones in biological material (adrenal tissue) (author's transl)

A rapid method is described for the determination of some steroidal hormones in adrenal tissue. The following steroids were measured: pregnenolone, progesterone, deoxycorticosterone, corticosterone, aldosterone, 17-alpha-OH-pregnenolone, deoxycortisol, cortisol, cortisone, 17-alpha-OH-progesterone, dehydroepiandrosterone, androstendione, and testosterone. After extraction of the steroids the purification steps were performed by thin layer chromatography. Gas chromatography was used for further separation and quantitative analysis of underivatized steroids. The GC-analysis of steroids without any derivatisation makes this procedure comparatively simple and exact. Recovery of the steroid content of the tissue ranged from 30% to 70%. This method described herewith has several advantages, and allows the analysis of two tissues at the same time for a large number of adrenal steroids within two weeks.     

固相萃取-气相色谱法测定大米中有机氯有机磷农药残留

采用固相萃取方法,结合气相色谱建立了同时检测大米中15种有机氯、有机磷农药残留的分析方法。样品用乙腈提取,氨基固相萃取柱净化,经DB-5石英毛细管柱分离后,直接用气相色谱(GC)检测,外标法定量。结果表明15种农药在0.01~0.2μg/mL浓度范围内呈现良好的线性关系,相关系数r均大于0.9951,样品在2个添加水平时的回收率为85.9%~103%,相对标准偏差(RSD)为1.3%~7.3%,检出限为0.002~0.004 mg/kg。该方法样品前处理简单、高效,测定的准确性好,灵敏度高,适用于大米中多种类农药残留的分析。     

Gas chromatographic determination of acenocoumarin in human plasma

A method based on solvent extraction, formation of a fluorinated derivative and quantitation by gas-liquid chromatography with electron-capture detection has been developed for the determination of acenocoumarin in plasma. The specificity and sensitivity of the procedure appear to be satisfactory for drug level measurements in human plasma. Its relative simplicity permits its use in routine analysis.     

Improved method for the on-line metal chelate affinity chromatography-high-performance liquid chromatographic determination of tetracycline antibiotics in animal products

An improved on-line metal chelate affinity chromatography-high-performance liquid chromatography (MCAC-HPLC) method for the determination of tetracycline antibiotics in animal tissues and egg has been developed. Extraction was carried out with ethyl acetate. The extract was then evaporated to dryness and reconstituted in methanol prior to on-line MCAC clean-up and HPLC-UV determination. Recoveries of tetracycline, oxytetracycline, demeclocycline and chlortetracycline in the range 42% to 101% were obtained from egg, poultry, fish and venison tissues spiked at 25 micrograms kg-1. Limits of detection less than 10 microgram kg-1 were estimated for all four analytes. This method has higher throughput, higher recovery and lower limits of detection than a previously reported on-line MCAC-HPLC method which involved aqueous extraction and solid-phase extraction clean-up.     

A method for determination of the absolute configuration of chiral glycerol residues in natural products using TEMPO oxidation and characterization of the glyceric acids formed

A method has been developed for determination of the absolute configuration of glycerol residues in natural products. It is required that the glycerol moiety contain a primary nonsubstituted hydroxymethyl group or that such a group can be obtained by modification without racemization. The method employs TEMPO oxidation of the primary hydroxyl group, hydrolysis, butanolysis with chiral 2-butanol, and acetylation. The acetylated (+)-2-butyl esters of the glyceric acid formed by oxidation are analyzed by gas-liquid chromatography. The esterification can also be performed with other chiral alcohols, e.g., (-)-2-octanol. The method is general and applicable to both primary and secondary substituted glycerols. It has recently been used for determination of the chiral glycerol-1-phosphate residue of the Escherichia coli O28 O-antigen, and now we report the absolute configurations of the glycerol moieties in Streptococcus pneumoniae type 18A and Streptococcus agalactaie type III. All studied glycerol residues were found to have the D-configuration.     

Residues of perchlorethylene and petroleum in rendered fats and in feeding meals

Methods were developed for the demonstration and determination of perchlorethylene and petrol in rendered fats and meals for feeding purposes. The methods are based on the collection and the vapours of extracting media over samples of rendering-plant products and on their identification and determination by gas chromatography. Under the conditions of the method, the limit of perchlorethylene extractibility is 0.05% and the limit of petrol extractibility is 0.01% (weight). Under adapted conditions the two limits can be reduced. The reproducibility of the results at practically occuring concentrations of residues in products is characterized by the value of the variation coefficient which reaches 2.79 in perchlorethylene and 6.05 in petrol. The maximum duration of the analysis of one sample is five minutes. In all media have been demonstrated to be present. Their content was high and considerably variable in the fats from rendering plants; in meat-bone meals from petrol extraction the content of residues reached only trace values. It is recommended to use the presented analytic methods for thorough and regular objective control of the residues of extracting media in the products of rendering plants for feeding purposes.     

The influence of steroids on erythropoiesis in mouse fetal liver cell cultures: relevance of cell cycle state

It has been shown that erythropoietin-mediated stimulation of heme synthesis in mouse fetal liver cells in vitro is correlated with hydroxyurea sensitivity. Assuming that OHU is specifically cytotoxic for cells in DNA synthesis this suggests that erythropoietin sensitivity may be related to this phase of the cell cycle. The direct effects of 19-nortestosterone and 3beta-hydroxy-5beta-pregnan-20-one on heme synthesis correlated with the capacity of these steroids to initiate DNA synthesis. It is suggested that the ability of these steroids to increase the proportion of cells in the Ep-sensitive phase of the cell cycle is probably the mechanism responsible for the erythropoietic effects of these agents. 17beta-hydroxy-5alpha-androstan-3-one appears to have a different mode of action since it has only minimal effects on heme synthesis and did not increase hydroxyurea sensitivity.     

Determination of risperidone in plasma by high-performance liquid chromatography with electrochemical detection: application to therapeutic drug monitoring in schizophrenic patients

A highly sensitive high-performance liquid chromatography method with electrochemical detection for the determination of risperidone in plasma has been developed. Remoxipride is used as an internal standard. A simple one-step extraction with 25% methylene dichloride in pentane is used to isolate the drug from the plasma. This is followed by high-performance liquid chromatography analysis on a cyano column with electrochemical detection. Under the experimental conditions described here, commonly coadministered drugs and other antipsychotic drugs did not interfere with the analysis of either risperidone or the internal standard. Also, the available two metabolites of risperidone did not interfere in the assay. This method has sufficient sensitivity to quantitate risperidone accurately at 0.1 ng/mL, when 1 mL of plasma was used for the analysis, with a coefficient of variation of < 9%. This method has been successfully used in the determination of plasma levels of risperidone in schizophrenic patients treated with 4-, 6-, and 8-mg oral doses per day.     

Analysis of cationic nutrients from foods by ion chromatography

This paper describes the feasibility of combining two relatively new technologies to generate data on the cationic nutrient content of foods. Single-column ion chromatography was used to monitor several analytes following the use of a microwave digestion scheme aimed at rapid, multiple sample digestion. The result is a more streamline and productive approach to multi-sample preparation and multi-analyte determination when investigating the cation content of foods. Linearity and limits of detection for the chromatographic procedure were established. Sample size as well as digestion acid type and amount were investigated during the microwave process. The method was applied to a variety of food matrices to evaluate its scope. Results generated with this method compare favorably to those from atomic absorption. Finally, capillary ion electrophoresis (Waters' trade name: Capillary Ion Analysis), a subset of capillary electrophoresis which has been optimized for ion analysis, was applied to the sample digests to investigate the usefulness of this technology to the analysis of mono-/divalent cations from foods.