高效液相色谱法同时测定妊娠合并乙型肝炎患者血浆中的吲哚与3-甲基吲哚

建立了一种高效液相色谱-荧光检测法用于同时测定血浆中的吲哚与3-甲基吲哚。样本经液液萃取法提取,采用Shim-Pack VP-ODS柱(150 mm×4.6 mm,4.6μm),以15 mmol/L磷酸二氢钠溶液-甲醇(40∶60,v/v)为流动相,甲奈酚为内标,荧光激发和发射波长分别为274 nm和340 nm。吲哚和3-甲基吲哚的线性范围分别为2.22~88.89μg/L和1.11~44.44μg/L;检出限分别为0.11μg/L(吲哚)和0.06μg/L(3-甲基吲哚);平均回收率为95.5%~112.3%,日内与日间相对标准偏差均小于6.8%。利用该方法对妊娠合并乙肝患者(n=29)和正常孕妇(n=46)的血浆进行了测定,结果表明妊娠合并乙肝患者血浆中吲哚和3-甲基吲哚水平均显著高于正常对照组,且与肝损伤指标转氨酶水平呈正相关。     

Cadmium levels in feed components and kidneys of growing/finishing pigs

Cadmium (Cd) concentrations in pig feeds (one control feed and one feed with reduced nitrogen content), straw, water, and pig kidney cortex were determined in 2 breeds of growing/finishing pigs (n = 96). The total Cd intake from feed was calculated. Feed mixtures and components, straw and kidney cortex samples, and certified reference samples were microwave-digested and analyzed by atomic absorption spectrometry with graphite furnace technique. Total Cd concentration in the control feed was 37.1 micrograms/kg wet weight (w.wt). The highest Cd levels were found in nonlocally produced feed components: vitamin-mineral mixture, lime, dicalcium phosphate, soybean meal, and rapeseed meal. These components contributed 70% of the Cd content in the feed. The main component, barley, which was locally produced, contributed 30% of the total Cd content in feed. The feed with reduced nitrogen content contained less soybean and rapeseed meal and a lower Cd level than the control feed. The Cd levels in kidney cortex varied from 38.0 to 105 micrograms/kg w.wt, with a mean level of 70.9 micrograms/kg. The levels differed between breeds and feeds, but not between gender. There was a significant correlation between Cd level in kidney cortex and age at slaughter, with an increase of 2.8 micrograms/kg w.wt in the kidney for each additional week of survival. The contribution of Cd from nonlocally produced feed components could have environmental effects through application of farmyard manure to local soils.     

Reference values of urinary 3,5,6-trichloro-2-pyridinol in the Italian population--validation of analytical method and preliminary results (multicentric study)

The interlaboratory validation of analytical procedures for the assay of urinary 3,5,6-trichloro-2-pyridinol (TCP) in the general Italian population is reported. The determinations were performed by high-resolution gas chromatography (HRGS) with electron capture detection and HRGS with mass spectrometry (MS) in 2 laboratories. The urine samples were from 42 participants from 3 regions of Italy. The results were evaluated by interlaboratory quality control. Urinary TCP concentrations were above the detection limit (1.2 micrograms/L) in 88% of the population, with a mean detectable concentration [GM (GSD)] of 2.8 (1.9) micrograms/g creatinine (creat). (GM, geometric mean; GSD, geometric standard deviation.) The Mann-Whitney U test showed that wine consumption was a statistically significant variable (p < 0.05) for urinary concentrations of TCP. Analysis of variance of the logarithm of urinary TCP versus wine consumption and diet showed a statistically significant fit. The model used explained 30% of the total variance: wine consumption and diet accounted for 37 and 17% respectively of the explained variance.     

Glycoalkaloid concentration in Alberta potatoes determined by matrix-assisted laser desorption/ionization mass spectrometry.

Matrix-assisted laser desorption and ionization (MALDI) mass spectrometry was used to determine concentrations of individual potato glycoalkaloids in tubers. Samples were extracted with methanol-water and deposited on 2,4,6-trihydroxyacetophenone crystals. Positive ions were analyzed with a MALDI time-of-flight mass spectrometer equipped with a 337 nm laser. Analyte ion intensities relative to an internal standard were used to determine chaconine and solanine concentrations. Calibration curves were prepared by standard additions to potato tuber material. The relative standard deviations (RSDs) of triplicate measurements ranged from 1 to 16%, with an average of 9%. The day-to-day RSD for replicate determinations was 11%. Recoveries of analyst-prepared spikes (50 micrograms/g) averaged 104% for chaconine (RSD, 8%) and 98% for solanine (RSD, 4%). The method limit of detection was estimated to be 2 micrograms/g.     

Characterization and determination of organic compounds in the mutagenic XAD-2 extracts of drinking water.

Amberlite XAD-2 extracts, which exhibit mutagenicity in the Ames assays, of drinking water sampled each month during the period from April 1988 to March 1989 were studied in order to characterize and determine the organic pollutants. The major organic pollutants were phthalate ester plasticizers such as dibutyl and di(2-ethylhexyl) phthalate. Several polynuclear aromatic hydrocarbons (PAHs) and the organocholorine pesticide oxadiazon were also identified to be present at low concentrations. The XAD-extractable and chromatographable organic pollutants were found to be composed of PAHs with a mean concentration of 0.136 micrograms/l(ca. 10% of the total amount of organic compounds detected), phthalates with a mean value of 0.405 micrograms/l(ca. 30%) and other compounds with a mean value of 0.845 micrograms/l(ca. 60%). The concentrations and compositions of these organic pollutants were correlated with the effective rainfall content of the river and with the water temperature.     

Homogeneous stopped-flow fluoroimmunoassay using europium as label

A competitive homogeneous fluoroimmunoassay (FIA) based on the use of europium(III) as label together with kinetic methodology, is described for the first time. This approach has been applied to the determination of skatole, a compound causing boar-taint, in pig back fat samples. The analytical signal was obtained by measuring the initial rate of the dissociation reaction of europium(III) from the tracer through the formation of an intense luminescent chelate. This initial rate is higher for the free tracer than for that corresponding to the tracer bound to the antibody, and it is directly related to the analyte concentration. Each kinetic measurement was obtained in less than 1 s by using stopped-flow (SF) mixing technique. Benzoyltrifluoroacetone, tri-n-octylphosphine and Triton X-100 were used to obtain an adequate luminescent signal. The dynamic range of the calibration graph of the method is 30–300 ng ml⁻¹ and the calculated detection limit is 11 ng ml⁻¹. The precision, obtained for two skatole concentrations, 50 and 150 ng ml⁻¹, and expressed as relative standard deviation (n=11), was lower than 6.5%. The method was applied to the analysis of pig back fat samples with recoveries ranging from 92 to 108%.     

Determination of abamectin and doramectin in sheep faeces using HPLC with fluorescence detection

An analytical procedure for the determination of abamectin and/or doramectin in sheep faeces has been developed. Avermectins were extracted from sheep faeces with acetonitrile, clean-up using solid phase extraction (SPE) and analysed by high performance liquid chromatography (HPLC) with fl uorescence detection after derivatization with N-methylimidazole.The method has a low detection limit (1.0 ng/g of moist sheep faeces), low quanti fi cation limit (2.5 ng/g of moist sheep faeces), good recovery in the range 66.4-80.8% for abamectin and 67.7-85.5% for doramectin as well as good repeatability (>85%). The method is applicable to the study of the time pro fi le of excretion in sheep faeces and also for ecotoxicological studies of both avermectins.     

Determination of cholesterol and cortisone absorption in polyurethane. I. Methodology using size-exclusion chromatography and dual detection.

A size-exclusion chromatographic method is described for measuring the absorption of the steroid-based lipids cholesterol and cortisone into Pellethane 2363, a polyurethane used in biomedical implants. The method uses refractometry and ultraviolet diode-array detection, with tetrahydrofuran as the mobile phase. Using an injection volume of 150 microliters, the lower limit of accurate measurement for cholesterol (refractive index detection) was 6 micrograms/ml with a lower limit of detection, based on a 2:1 signal-to-noise ratio, of 0.15 micrograms (1 microgram/ml). For cortisone (ultraviolet detection), the lower accurate limit was 0.6 micrograms/ml with a lower limit of 0.015 micrograms (0.1 micrograms/ml). The results show that after 44 h, 2037 micrograms/g cholesterol and 3131 micrograms/g cortisone were absorbed by the polyurethane. The method eliminates extensive sample manipulation and is sensitive to low levels of lipid in the presence of a high-molecular-mass synthetic polymer.     

High-performance liquid chromatographic determination of a new beta-lactamase inhibitor and its metabolite in combination therapy with piperacillin in biological materials

[2S-(2 alpha,3 beta,5 alpha)]-3-Methyl-7-oxo-3-(1H-1,2,3-triazol-1-yl- methyl)-4-thia-1-azabicyclo [3.2.0]-heptane-2-carboxylic acid 4,4-dioxide (YTR-830H) is a new beta-lactamase inhibitor and the combination therapy of this compound with piperacillin is now under study. For the determination of the beta-lactamase inhibitor and piperacillin in biological materials, plasma and visceral tissue homogenates were deproteinized, whereas diluted urine and filtered faeces homogenates were treated with a Sep-Pak C18 cartridge. In order to assay the inactive metabolite of beta-lactamase inhibitor, each sample was treated with a Sep-Pak C18 cartridge. Aliquots of each preparation were chromatographed using ion-pair and reversed-phase chromatographic techniques on a high-performance liquid chromatograph equipped with a UV detector, set at 220 nm. The detection limits of beta-lactamase inhibitor and piperacillin were 0.2 microgram/ml in plasma, 2.5-5.0 micrograms/ml in urine and 0.2-0.5 microgram/g in visceral tissue and faeces. Those of the metabolite were 1.0 microgram/ml in plasma, 2.5-5.0 micrograms/ml in urine and 1.0 microgram/g in visceral tissue and faeces. A precise and sensitive assay for the determination of the beta-lactamase inhibitor, its metabolite and piperacillin is described, and their stabilities in several media are reported.     

Determination of hexahydrophthalic anhydride in air using gas chromatography.

Two methods for the determination of hexahydrophthalic anhydride (HHPA) in air were developed. In a solid sorbent method, HHPA was sampled in Amberlite XAD-2 tubes, eluted in toluene and analysed by gas chromatography with flame ionization detection. The sampling rates were 0.2 and 1.0 l/min. At 15 micrograms/m3 (relative humidity less than 2%) and 27 micrograms/m3 (relative humidity 70%) no breakthrough was observed. However, at 160 micrograms/m3 (relative humidity less than 2%), 6% breakthrough was found. The sampling efficiency of the sampling rates 0.2 and 1.0 l/min did not differ. In a bubbler method, HHPA was sampled in bubblers filled with 0.1 M sodium hydroxide solution. The sodium salt of hexahydrophthalic acid was formed. No breakthrough was observed using a sampling rate of 1.0 l/min. The samples were stable during storage for eight weeks in a refrigerator. The HHP acid was esterified with methanol-boron trifluoride and analysed by gas chromatography-flame ionization detection. Apparatus for the generation of standard atmospheres of HHPA, in the range of 10-3000 micrograms/m3, was developed using the diffusion principle. For the solid sorbent method the precision (coefficient of variation) of the overall method was 2-7%, and for the bubbler method 3-19% (range 15-160 micrograms HHPA/m3; relative humidity = less than 2-70%). A comparison between the two methods was performed using the standard atmosphere. The concentrations found by the solid sorbent method were 86-98% of those found by the bubbler method (range 15-160 micrograms HHPA per m3; relative humidity = less than 2-70%). In work environment air, 93% was found using the solid sorbent method relative to the bubbler method at a mean concentration of 330 micrograms/m3 (coefficient of variation = 39%; range 200-540 micrograms/m3). For both methods, concentrations greater than 3 micrograms/m3 could be quantified at 60 min sampling with a sampling rate of 1.0 l/min.     

Rates and mechanisms of indole and 3-Methylindole polymerization in cation exchange resin beads

Batch extraction and polymerization of indole and 3-methylindole (skatole) with acidic cation exchange resins functioned as pseudo first-order reactions. Activation energies of 3.4 and 5.7 keal/mole indicated greater steric hindrance to skatole polymerization, as would be expected from 2,2′ bonding of skatole compared to 3,2′ bonding for indole. Linear polymerization occurred, although a heterocyclic ring opened at the trimer stage of poly(indole). 2-Methylindole did not polymerize. General acid-base catalysis caused unreproducible partial depolytnerization when the polymers were extracted from resin beads. Thus, compounds chromatographically separated probably were of lower degree of polymerization than were the polymers formed in the resin matrix.     

Residue study of doxycycline and 4-epidoxycycline in pigs medicated via-drinking water.

A study was performed to determine the residues in edible tissues of healthy pigs after continuous administration of doxycycline with drinking water for five consecutive days at a dose rate of 10.5 mg doxycycline kg-1 body weight (BW) per day. Quantitation was performed using a validated HPLC method with fluorescence detection. The method was able to separate doxycycline and its 4-epimer, 4-epidoxycycline. This epimer was found in kidney, liver, skin, fat and muscle tissue. The method was validated at the maximum residue limit (MRL), at half the MRL and at double the MRL for both doxycycline and 4-epidoxycycline. Linear calibration curves were obtained in spiked tissues (r > 0.99). The accuracy of the calibrators of the calibration curves was within -20% to +10%. The accuracy and precision (expressed as the within-run repeatability) were found to be within the required ranges for the specific concentration. The limits of detection and limits of quantification were below one-half of the MRL. The quantification limits were 50 micrograms kg-1 for doxycycline and 100 micrograms kg-1 for 4-epidoxycycline in kidney and liver, 20 micrograms kg-1 for doxycycline and 50 micrograms kg-1 for 4-epidoxycycline in skin and fat and 10 micrograms kg-1 for doxycycline and 50 micrograms kg-1 for 4-epidoxycycline in muscle tissue. The withdrawal time was calculated according to the recommendations of the European Agency for the Evaluation of Medicinal Products (EMEA/CVMP/036/95) and was set at 3 days. The plasma concentration of doxycycline and the stability of doxycycline in drinking water were also determined during the treatment period. The mean plasma concentration of doxycycline during the treatment period ranged from 0.83 to 0.96 microgram ml-1. Thirty-six hours after the withdrawal from medicated drinking water, no plasma levels could be detected. Samples of medicated water were taken at time zero and at 24 h after addition of doxycycline to the drinking water. No statistically significant difference in the mean drinking water concentration was seen at time zero and at time 24 h (Student's t-test, alpha = 0.05).     

Photosensitizers for tumor therapy: determination of bis(di-isobutyl octadecylsiloxy)silicon 2,3-naphthalocyanine (isoBOSINC) in rat tissue and serum by high-performance liquid chromatography.

Bis(di-isobutyl octadecylsiloxy)silicon 2,3-naphthalocyanine (isoBOSINC) is a synthetic potential photosensitizer for tumor therapy. A new method, which combines solvent extraction and several purification steps, has been developed to determine its presence in tissues. Separation and quantitation of isoBOSINC is done by high-performance liquid chromatography on a silica column with toluene as a mobile phase and using fluorescence detection (lambda ex = 365 nm, lambda em = 750 nm). For recovery studies, isoBOSINC was added to muscles at levels of 0.067 and 0.67 micrograms/g; the mean recoveries were 100%, with coefficients of variation of 6.1 and 6.4%, respectively. For liver samples, the amounts added were 0.67 and 6.7 micrograms/g and for serum 0.67 and 6.70 micrograms/ml. The mean recoveries for liver were 86 and 93%, with coefficients of variation of 7.7 and 4.4%, respectively. For serum, the mean recoveries were 99 and 96%, with coefficients of variation of 2.6 and 6.9%, respectively. Due to its low detection limit and selectivity, the method is appropriate for pharmacokinetic as well as tumor uptake studies following in vivo exposure to isoBOSINC. Preliminary data on tissue distribution of the photosensitizer in normal rats are also presented.     

High-performance liquid chromatographic determination of cefonicid in human plasma and urine

A high-performance liquid chromatographic assay for determination of cefonicid concentrations in human plasma and urine samples has been developed using cefazolin as an internal standard. For the analysis of plasma samples two calibration curves were utilized covering the cefonicid concentration ranges of 0.05-1.0 microgram/ml and 1.0-50.0 micrograms/ml, respectively. Coefficients of variation of 7.4% or less were obtained for cefonicid concentrations of 0.05-50.0 micrograms/ml. Mean bias was +6.0% at 0.05 micrograms/ml cefonicid and between -2.1% and +1.6% for 1.0-50.0 micrograms/ml cefonicid. Plasma samples containing 30 ng/ml cefonicid could be well distinguished from blank plasma samples. Urine samples were analysed by using a calibration curve for cefonicid concentrations between 1.0 and 50.0 micrograms/ml. ranged from 8.6% at a cefonicid concentration of 1.0 microgram/ml to 0.5% at 50.0 micrograms/ml with a mean bias between -3.0% and +0.3%.     

Preliminary study of HCHO spatial and temporal distribution from Coastal to Plateau areas in Antarctica

Formaldehyde concentrations were determined in over 1800 snow samples (snowpit, firn cores and superficial snow) from Antarctica by a sensitive spectrofluorimetric Flow Injection Analysis method. The method performances (detection limit: 55?ng/L; reproducibility: 2.5% at 1?µg/L level; linear range: 0.1–3000?µg/L) allowed a reliable determination of formaldehyde content in all the collected samples. The range of determined concentrations was 0–70?µg/L with a mean concentration of 7.7?µg/L and a median concentration of 5.8?µg/L. The formaldehyde background level was estimated at a few micrograms per liter in coastal and plateau areas of Northern Victoria Land. In some stations the background values are modulated by HCHO deposition events recurring over relatively large time periods.     

气相法分析3-氯-2-羟丙基三甲基氯化铵中的微量有机杂质

 以氯仿为萃取剂 ,对 3 氯 2 羟丙基三甲基氯化铵 (CHPTMA)水溶液进行萃取 ,用气相法分析了CHPT MA溶液中的微量有机杂质环氧氯丙烷和 1 3 二氯丙醇。柱为 2m× 3mmi d 的不锈钢填充柱 ,固定相为10 %的PEG 2 0M ,载体为ChromosorbW/AW。环氧氯丙烷和 1,3 二氯丙醇的回收率分别为 97 5 %～ 10 5 0 %和93 3%～ 98 8% ,相对标准偏差分别为 11 5 %和 13 1% ,最低检测限分别为 5 0 μg/g和 10 0 μg/ g。     

Simplified procedure for the determination of sotalol in plasma by high-performance liquid chromatography

A simple, specific and rapid reversed-phase high-performance liquid chromatographic (HPLC) procedure for sotalol determination is described requiring small plasma volumes. The high recovery of sotalol from plasma and the high precision of measurement obviate the need for an internal standard. Plasma samples (300 microliters) were deproteinised with 50 microliters of 70% (w/w) perchloric acid in disposable glass tubes. After vortex-mixing and centrifugation, 30 microliters of 4 M K2HPO4 were added followed by gentle shaking. A 20-microliters aliquot was then injected (by autosampler) for HPLC analysis. Chromatography was performed on a glass-lined 250 mm x 4 mm 5-micron C18 steel column. The mobile phase was 6% (v/v) acetonitrile in 0.08 M KH2PO4 buffer (pH 4.6). The flow-rate was 0.8 ml/min. Detection was by fluorescence with excitation and emission wavelengths at 235 and 310 nm, respectively. The retention time for sotalol was 7.1 min. Calibration was linear from 0.16 to 10 micrograms/ml in plasma (r greater than 0.999 for detector response to sotalol). The minimum concentration for quantitation was 0.08 micrograms/ml [within assay coefficient of variation (C.V.) less than 5%]. Recovery was near quantitative (greater than 98%) and replicate (intra-assay precision was less than 5% C.V.). Analysis of samples (n = 10) at concentrations of 0.42 and 4.2 micrograms/ml gave mean values of 0.44 and 4.3 micrograms/ml, respectively. The inter-assay C.V. values were 4.5 and 2.2%, respectively. Other clinically used antiarrhythmic drugs did not interfere. This assay can be performed using other commercial C18 analytical columns by suitable adjustment of mobile phase flow-rate and acetonitrile composition.     

Determination of fenbendazole and its metabolites in trout by a high-performance liquid chromatographic method.

A high-performance liquid chromatographic (HPLC) method based on solid phase extraction was developed for the simultaneous determination of fenbendazole (FBZ), fenbendazole sulfoxide (FBZ-SO) and fenbendazole sulfone (FBZ-SO2) in trout muscle and skin tissues. The compounds were extracted with acetonitrile and the extract was concentrated and cleaned up by solid phase extraction on C18 and CN cartridges. The extract was analysed by reversed-phase gradient HPLC on a C18 column followed by ultraviolet detection at 290 nm. The method's detection limits were 4.0 micrograms kg-1 for FBZ, 4.5 micrograms kg-1 for FBZ-SO and 3.8 micrograms kg-1 for FBZ-SO2. The mean recovery in muscle was 88% for FBZ, 94% for FBZ-SO and 92% for FBZ-SO2 at a level of 5-150 micrograms kg-1. The corresponding mean recoveries in skin tissue were 88, 81 and 86% at a level of 10-100 micrograms kg-1. The mean relative repeatability standard deviation was 9.2% at a level of 5 micrograms kg-1, 5.9% at a level of 10-100 micrograms kg-1 and 2.3% at a level of 150 micrograms kg-1. The method was applied to trout given feed containing FBZ in an aquaculture pilot plant. The three compounds FBZ, FBZ-SO and FBZ-SO2 were all detected in muscle and skin tissues shortly after administration. The concentrations were generally highest in skin tissue.     

Determination of glycarbylamide in chicken tissue by high-performance liquid chromatography

A high-performance liquid chromatographic (HPLC) method for determining glycarbylamide (GB) in chicken tissue was developed. GB was extracted with acetonitrile, followed by solid-phase extraction cleanup using a Bond Elut cartridge column with neutral alumina. After the extract had been evaporated to dryness, the residue was dissolved in 1.0 mL 0.1 N sodium hydroxide. Then 1.0 mL 0.1 M potassium dihydrogen phosphate solution was added to it. HPLC separation was done on a 250 x 4.6 mm id TSK-GEL ODS 80 column with 0.05M potassium dihydrogen phosphate as the mobile phase. Ultraviolet detection was done at a wavelength of 260 nm. The calibration curve of standard GB solutions was linear between 0.16 and 3 micrograms/mL (correlation coefficient, r = 0.999). The recovery of GB from chicken muscle spiked at 0.8 microgram/g was 88.6 +/- 2.3% (mean +/- standard deviation, n = 5), and the lower limit of determination was 0.05 microgram/g in chicken muscle.     

Validation of a solid-phase microextraction method for the determination of organophosphorus pesticides in fruits and fruit juice

A method for the determination of organophosphorus pesticides (diazinon, fenitrothion, fenthion, quinalphos, triazophos, phosalon and pyrazophos) in fruit (pears) and fruit juice samples was developed and validated. The samples were diluted with water, extracted by solid-phase microextraction (SPME) and analysed by gas chromatography (GC) using a flame photometric detector in phosphorous mode. Limits of detection of the method for fruit and fruit juice matrices were below 2 micrograms/kg for all pesticides. Relative standard deviations for triplicate analyses of samples fortified at 25 micrograms/kg of each pesticide were not higher than 8.7%. Recovery tests were performed for concentrations between 25 and 250 micrograms/kg. Mean recoveries for each pesticide were all above 75.9% and below 102.6% for juice, and between 70 and 99% for fruit except for pyrazophos in the fruit sample (with mean recovery of 53%). Therefore, the proposed method is applicable in the analysis of pesticides in fruit matrices and the use of the method in routine analysis of pesticide residues is discussed.