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1.
An analytical method has been developed that uses electron capture/gas-liquid chromatography to determine Mirex in serum containing polychlorinated biphenyls (PCBs) (Aroclor 1260). With this method, 0.2 ppb Mirex can be determined in 4 mL serum that also contains 10 ppb PCBs. The method provides approximately 70% recovery of Mirex at 1.0 and 3.5 ppb. The coefficients of variation are 4.5 and 4.6% at 1.0 and 3.5 ppb, respectively. In a cooperative study with the Ohio Department of Health, the Centers for Disease Control used this method to determine the extent of exposure of Salem, OH, residents to Mirex. Confirmation of Mirex was obtained by using high resolution gas chromatography and high resolution mass spectrometry.  相似文献   

2.
A method for the determination of polybrominated biphenyls (PBBs) in dairy products is described. Fat is extracted from the products by the official AOAC method. The PBB residues are separated from the fatty material by gel permeation chromatography prior to gas-liquid chromatographic (GLC) quantitation. An additional cleanup using petroleum ether elution through a miniature Florisil column is necessary for thin layer chromatographic (TLC) confirmation. Recoveries of PBBs from samples fortified at levels from 0.1 to 0.5 ppm ranged from 94 to 104% with an average of 99%. GLC sensitivity permits the estimation of PBB residue levels as low as 0.007 ppm. Routine TLC confirmation is limited by sensitivity to greater than or equal to 0.2 ppm.  相似文献   

3.
A new liquid chromatographic method for determination of ampicillin in canine and equine serum has been developed. The serum sample (500 microL) is vortex-mixed with 20% ethanol (500 microL) and filtered using a 30,000 molecular weight cutoff microseparation tube to separate high molecular weight solutes following low-speed centrifugation. Ampicillin is then separated from other serum components by reverse phase ion-pair liquid chromatography (LC). The ultraviolet (UV) absorbance of the column effluent is monitored at 230 nm. Recoveries of ampicillin from canine serum spiked at concentrations of 10, 40, and 60 micrograms/mL were 93.1, 100.9, and 87.8%, respectively, with coefficients of variation (CVs) of 2.91, 3.08, and 4.08%, respectively. Recoveries of ampicillin from equine serum spiked at the same concentrations were 91.6, 90.1, and 88.7%, respectively, with CVs of 3.03, 2.61, and 3.35%, respectively. The limit of detection for ampicillin by this method is less than 0.5 micrograms/mL serum.  相似文献   

4.
A gas chromatographic-electron capture detection method for determining the concentration of polychlorinated biphenyls (PCBs) as Aroclor 1254 (AR 1254) in serum was evaluated through a 2-phase collaborative study. In Phase I, each collaborator's lot of Woelm silica gel (70-150 mesh) was evaluated for elution and recovery of AR 1254, which had been added in vitro at 25 ng/mL to a serum extract. In Phase II, each collaborator analyzed a series of bovine serum samples that contained the following: (1) in vitro-spiked AR 1254; (2) in vivo AR 1254 and 8 in vitro-spiked chlorinated hydrocarbons; (3) in vivo AR 1254 only; (4) 8 in vitro-spiked chlorinated hydrocarbons only; and (5) neither AR 1254 nor chlorinated hydrocarbons above the detection limit of the method. In Phase I, the average recovery of AR 1254 from silica gel for the 6 collaborators was 87.9 +/- 15.44% (mean +/- 1 SD; N = 18; range = 52.3-105.8%). In Phase II, the analysis of in vitro spikes of AR 1254 in serum at 8.58, 16.8, 41.8, and 84.3 ppb gave mean (means) interlaboratory recoveries of 89.0, 83.3, 79.4, and 76.9%, respectively, with within-laboratory (repeatability) relative standard deviations (RSDr) of 18.8, 20.5, 10.2, and 14.1%, respectively, and among-laboratory (reproducibility) relative standard deviations (RSDR) of 21.5, 21.1, 14.6, and 20.8%, respectively. The determination of in vivo AR 1254 in samples containing approximately 10, 25, 50, and 100 ng/mL of AR 1254 resulted in interlaboratory means of 10, 22, 39, and 79 ng/mL, respectively, with RSDr = 6.7, 9.7, 6.4, and 5.8%, respectively, and RSDR = 20.6, 16.0, 10.9, and 10.3%, respectively. The precision of the method for incurred AR 1254 showed a maximum RSDr of less than 10% and a maximum RSDR of less than 21% for a concentration range of 10-100 ng/mL. The accuracy of the method as demonstrated by the mean recovery of in vitro-spiked AR 1254 over a concentration range of 8.58-843 ng/mL was 82.2%. The method has been approved interim official first action.  相似文献   

5.
A simplified method for determining polychlorinated biphenyls (PCBs), phthalates, and benzene hexachlorides (BHCs) in air has been developed. Florisil is used as the adsorbent, and compounds are eluted by liquid chromatography with 10% 2-propanol in hexane. PCBs are separated from phthalates plus BHCs on a cyanopropyl column with a gradient containing 10% 2-propanol in hexane and 100% hexane as the mobile phase. Two fractions are collected: one contains PCBs and the other contains phthalates plus BHCs, which are then determined by gas chromatography using a 63Ni electron-capture detector and a DB-5-bonded, fused-silica capillary column.  相似文献   

6.
A procedure was developed to determine chlorinated methylthiobenzenes and their respective sulfur oxidation products in fish. Perch samples fortified at the 0.1 ppm level with 2,4,5-trichloromethylthiobenzene, pentachloromethylthiobenzene, and their sulfoxides and sulfones were extracted and cleaned up using an adaptation of the official AOAC method for multiple residues of organochlorine pesticides. The Florisil column cleanup was modified; 200 mL 6% petroleum etherethyl ether eluted the methylthiobenzenes, 200 mL 50% PE-EE eluted the sulfones, and 200 mL EE eluted the sulfoxides. Recoveries determined by electron capture (ECD) gas chromatography (GC) were 75-101% for the methylthiobenzenes and their sulfones and 63-93% for the sulfoxides. Co-extracted materials in the Florisil eluates that interfered with the ECD/GC quantitation were removed by partitioning the sulfoxides and sulfones into sulfuric acid and by thin layer chromatography on silica gel, using methylene chloride-hexane (50 + 50) as the developing solvent. Seven fish samples containing residues of chlorinated benzenes or polychlorinated biphenyls (PCBs) were examined for chlorinated methylthiobenzenes, methylthio-PCBs, and their oxidation products by matching GC retention times obtained with the EC detector and a flame photometric detector operated in the sulfur mode. These analytes were not found in the fish samples above a detection level equivalent to 0.02 ppm 2,4,5-trichloromethylthiobenzene.  相似文献   

7.
A sensitive liquid chromatographic method was developed for determining oxacillin, cloxacillin, and dicloxacillin (simultaneously), and penicillin G, amoxicillin, carbenicillin, and ticarcillin in canine and/or equine serum. The method involves filtering diluted serum through a 30,000 molecular weight cut-off filter and separating penicillins from other serum components by ion-pair liquid chromatography using a reverse-phase column eluted with acetonitrile-water solutions. The ultraviolet absorbance of the column effluent was monitored at 230 nm. Recoveries of oxacillin, cloxacillin, dicloxacillin, and penicillin G (spiked at 2.5 micrograms/mL), amoxicillin (spiked at 5 micrograms/mL), and carbenicillin and ticarcillin (spiked at 10 micrograms/mL) from canine and equine serums ranged from 78.3 to 104.4% with coefficients of variation ranging from 3.35 to 5.95%. The limit of detection for these penicillins was 0.02-0.05 microgram/mL.  相似文献   

8.
A gas chromatographic method is described for the analysis of human milk to determine polychlorinated biphenyls (PCBs) as 72 congeners plus p,p'-DDE, mirex, hexachlorobenzene, and octachlorostyrene. The detection limit for individual compounds is about 0.05 ng/g when 30 g milk is analyzed. Total PCBs can be estimated with a detection limit of 1-5 ng/mL milk. Analytical precision is better than +/- 10% for all compounds at 20-50 ng/mL whole milk.  相似文献   

9.
This study includes the determination of five indicator polychlorinated biphenyls (PCBs) (52, 101, 153, 138, and 180), six non-ortho PCBs (35, 80, 81, 77, 126, and 169), and two mono-ortho PCBs (28 and 118) in fast food for children. A freeze-dried sample of 10 g is extracted by using pressurized n-hexane in two 5 min cycles at 120 degrees C and 100 mbar. Fatty extracts were cleaned up by means of acetonitrile/n-hexane partitioning and gel-permeation chromatography. The fractionation of non-ortho, mono-ortho, and indicator PCBs was made on graphitized carbon solid-phase extraction cartridges by using n-hexane, n-hexane/toluene (99:1, v/v), and toluene as elution solvents. Gas chromatography coupled to tandem mass spectrometry and large-volume injections with a programmed-temperature vaporizer (PTV-LV) were used to increase sensitivity and selectivity of the PCB determination. The PTV-LV injection settings, that is, vaporizing temperature, vaporizing time, and purge flow, were optimized by using a central composite design. A 15-40 times increased sensitivity was reached as compared with that obtained with the conventional 1 microL splitless injection. The limits of detection achieved were between 0.3 and 1.2 pg/g, and repeatability data, as relative standard deviation varied, ranged from 2 to 9% for the 0.05 ng/mL PCB level.  相似文献   

10.
Determination of thiamphenicol in bovine plasma by liquid chromatography   总被引：1，自引：0，他引：1  
A liquid chromatographic method is described for the measurement of thiamphenicol in bovine plasma. The plasma (1 mL) is extracted with ethyl acetate. After the solvent is evaporated under a stream of nitrogen, the residue is reconstituted in methanol-water and analyzed by reverse-phase liquid chromatography with UV detection at 224 nm. The intra-day recoveries for bovine plasma spiked with 5 and 50 micrograms/mL of thiamphenicol were 102 and 101%, respectively, with coefficients of variation of 2.40 and 0.28%, respectively. The interday recoveries for the 5 and 50 micrograms/mL samples were 103 and 101%, respectively, with coefficients of variation of 3.40 and 0.94%, respectively. The sensitivity of the method allows quantitation to at least the 100 ng/mL level.  相似文献   

11.
Ractopamine hydrochloride is a beta-adrenergic leanness-enhancing agent approved for use in swine in the United States. Depletion of ractopamine and its metabolites from animal tissues, urine, and serum is of interest for the detection of illegal use. The objectives of this study were to measure the residues of ractopamine in swine incurred samples after treatment with dietary ractopamine for 28 consecutive days. An efficient and sensitive analytical method was developed for the detection of parent ractopamine and its metabolites in swine tissues, urine, and serum by HPLC-FLD. After extraction, enzymatic digestion, and solid-phase cleanup of the samples, ractopamine residues were determined by liquid chromatography (LC) with fluorescence detector. The limits of detection (LOD) for tissues, urine, and serum were 1 ng g(-1), 0.5 ng mL(-1), and 0.5 ng mL(-1), respectively. Recoveries ranged from 70.5 to 94.5% for samples fortified at 1-50 ng g(-1) or ng mL(-1). Sixty pigs were fed twice daily for 28 consecutive days with feeds containing 18 mg kg(-1) ractopamine HCl. The residue concentrations in urine, liver, and kidney were 650.06 ng mL(-1), 46.09 ng g(-1), and 169.27 ng g(-1), respectively, compared with those in muscle, fat, and serum (4.94 ng g(-1), 3.28 ng g(-1), and 7.48 ng mL(-1), respectively) at the feeding period of 7 days. The residue concentrations at withdrawal period of 0 days in all edible tissues were lower than tolerance values established by the FDA and MRL values listed by the JECFA. These data support the withdrawal time of 0 days established by the FDA for ractopamine used as feed additive in swine.  相似文献   

12.
As part of an epidemiology study, extraction methods and extract cleanup procedures were developed and validated for polychlorinated biphenyls (PCBs) and DDE, an ubiquitous metabolite of DDT, in human milk, blood serum, and infant formula. Studies included quantitative and reproducible recovery of total lipids, and reproducible and reasonably high recoveries of these chlorinated compounds from the human body fluids and infant formula, including levels of environmental health interest. An extensive quality control and assurance program was designed for use with these methods. Some validation work on serum was done using radiolabeled 14C-Aroclor 1254. Dilution assays were developed to permit use of a constant procedure, which should minimize variability in results. Methods are based on selected organic solvent extraction and column chromatographic cleanup techniques and quantitation by electron capture gas chromatography (EC/GC). Using these extensively researched extraction and cleanup methods, the limits of detection for GC measurements were 10.0 and 2.00 ppb for PCBs and DDE, respectively, in milk and 4.00 and 0.80 ppb in serum.  相似文献   

13.
A sensitive liquid chromatographic method has been developed for the simultaneous determination of oxytetracycline, minocycline, tetracycline, and doxycycline in serum. A serum sample is vortex-mixed with a solution of mobile phase for tetracyclines and 2% (v/v) phosphoric acid. The mixture is filtered using a 30,000 molecular weight cutoff microseparation tube which separates high-molecular-weight solutes following low-speed centrifugation. Tetracyclines are separated from other serum components by reverse phase liquid chromatography (LC) with buffered methanol mobile phase. Ultraviolet absorbance of the column effluent is monitored at 267 nm. Concentrations as low as 0.2 micrograms/mL of tetracyclines in serum are quantitatable, with recoveries from 76.2 to 102.6% and coefficients of variation from 2.69 to 5.36%. The method has been tested in bovine, porcine, equine, caprine, ovine, canine, feline, and avian (turkey) serum.  相似文献   

14.
A gel permeation chromatographic (GPC) method, used by the U.S. Environmental Protection Agency (USEPA), was modified for cleanup of soil, sediments, wastes, and oily wastes before determination of semivolatile organic pollutants. The modifications included new calibration procedures and control of the amount of material processed. The modifications were evaluated for soil and sediment matrixes in a 5-laboratory study where each laboratory processed a solution containing a phthalate, substituted phenols and benzenes, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), nitroaniline, and pesticides. With the exception of nitroaniline, analyte recoveries were 87-112%, with relative standard deviations (RSDs) of 6.7-26%. Soil samples containing PCBs and fortified with 6 pesticides at 0.7-4 micrograms/g were also analyzed by the 5 laboratories. The mean recovery of the 6 pesticides was 100% with a mean RSD of 16%. Mean RSD for the determination of total PCBs was 8.9%. An additional modification for the processing of wastes and high concentration waste samples was attempted; this involved GPC processing of sample extracts dissolved in 1 + 1 butyl chloride-methylene chloride. This modification did not improve recoveries of the semivolatile analytes. Finally, the modified GPC protocol was applied to PCB-contaminated reclaimed waste oils samples. Two GPC cleanup steps were used to separate PCBs from the waste oil samples before PCBs were determined by gas chromatography combined with electron-capture detection (GC/ECD).  相似文献   

15.
针对持久性有机污染物在水生生物体内易于积累的特性,利用气相色谱与质谱联用技术（GC-MS）,检测了白洋淀8种鱼类体内多氯联苯（PCBs）含量,并分析了同系物组成特征。根据白洋淀鱼类检测到同系物情况,计算毒性当量（TEQ）并进行评价。白洋淀8种鱼类体内PCBs平均含量范围是55.85~1 485.74 ng.g-1脂肪重,从高到低的顺序依次为黄颡〉黄鳝〉乌鳢〉泥鳅〉鲤鱼〉鳙鱼〉鲫鱼〉鲇鱼。在8种鱼类PCB同系物组成中,四氯联苯和五氯联苯是主要的同系物,其相对百分含量为52.0%~84.3%。这种组成模式反映了白洋淀地区有多氯联苯工业品的使用历史。8种鱼类体内PCBs的毒性当量（TEQ）范围是0.09~1 412.87 pg TEQ.g-1脂肪重,其大小顺序依次为鳙鱼〉鲫鱼〉鲇鱼〉黄颡〉黄鳝〉鲤鱼〉乌鳢〉泥鳅。结果表明,白洋淀淀区部分鱼类已经受到PCBs一定程度的污染,应引起重视。  相似文献   

16.
Hypoxoside is a norlignan diglucoside present in the corms of African potato (Hypoxis hemerocallidea). The latter is used as a popular African traditional medicine for it's nutritional and immune-boosting properties. A reverse phase high-performance liquid chromatography method was developed and validated for the determination of hypoxoside using a mobile phase consisting of acetonitrile:water (20:80, v/v). The method was linear throughout the range of 10-100 microg/mL and provided a high degree of accuracy (100 +/- 4%). The recovery of the method was found to be 100 +/- 5%, and the precision of the study, % relative standard deviation intraday and interday (over three separate days), was better than 6.15 and 5.64%, respectively. The limits of detection and quantification were calculated to be 0.75 and 3.5 microg/mL, respectively. This method was applied to the analysis and quality control of African potato corms as well as 12 commercially available products. The daily intake of hypoxoside through traditionally prepared African potato decoction was also evaluated.  相似文献   

17.
In this paper, a new monoclonal antibody (Mab) against sulfamethoxypyridazine (SMP) was produced, and a fluorescence polarization immunoassay (FPIA) based on the produced Mab was developed and optimized for the qualitative screening analysis of SMP. The Mab was raised from mice immunized with SMP linked to bovine serum albumin (BSA) by carbodiimide activated ester formation, using a succinic anhydride spacer molecule between SMP and BSA. Fluorescein labeled sulfachloropyridazine (SCP) and SMP (tracer) were synthesized and purified by thin layer chromatography (TLC). The developed screening FPIA method can tolerate up to 20% methanol, and satisfactory assay sensitivity can be obtained between pH 4 and pH 8 and at lower salt concentration. The anti-SMP Mab exhibited a high cross-reactivity with SCP. The effect of the tracer structure on the analytical characteristic of the determination and on antigen-antibody binding constants was studied. The limits of detection (LOD) were 0.7 ng/mL for SMP and 0.25 ng/mL for SCP in buffer, respectively, whereas negligible cross-reactivities were exhibited by related sulfonamides. Analysis of SMP and SCP-fortified milk samples by the FPIA showed average recoveries from 60 to 145%.  相似文献   

18.
The efficacy of a combination of two enzyme-linked immunosorbent assay (ELISA) kits was examined for screening the toxic equivalent (TEQ) concentrations of dioxins in retail fish. The coplanar PCB-EIA system, which is a competitive immunoassay specific for polychlorinated biphenyl (PCB) 118, was tested as a screening method for mono- ortho PCBs. The Ah immunoassay (Ah-I), which is an ELISA-based aryl hydrocarbon receptor binding assay, was analyzed for its screening ability for non- ortho PCBs, polychlorinated dibenzo- p-dioxins (PCDDs), and dibenzofurans (PCDFs). Dilution and recovery tests using purified fish extracts revealed no major interference of the matrix in the PCB-EIA and suggested that the matrix effect was minimized in the Ah-I. Finally, the results for the fish samples ( n = 20) showed a strong correlation between this method and high-resolution gas chromatography coupled to high-resolution mass spectrometry for the determination of the TEQ concentrations of mono- ortho PCBs ( r = 0.99) and non- ortho PCBs and PCDD/Fs ( r = 0.97). These data indicate that our method is suitable for screening retail fish to determine the TEQ concentrations of dioxins.  相似文献   

19.
A method for determining serum zinc concentrations was collaboratively studied by 9 laboratories. Serum samples in polypropylene tubes are directly diluted with 0.03% Brij 35, and zinc is determined by flame atomic absorption spectrophotometry (AAS). A certified standard reference material serves as an external control. Repeatability relative standard deviations (RSDr) were 1.2 and 11.4% and reproducibility relative standard deviations (RSDR) were 6.1 and 12.9% for serum zinc concentrations of 6.36 and 0.63 micrograms/mL, respectively. The method has been approved interim official first action by AOAC.  相似文献   

20.
A micellar electrokinetic capillary chromatography (MECC) mode was applied to a capillary electrophoresis (CE) method, which was developed for detection and quantitation of patulin in apple ciders. This method used a small sample amount (2 mL) and consumed minimal organic solvent compared to the most commonly used HPLC methods. The sample preparation procedure of the CE method was also simpler than other chromatographic techniques developed for patulin analysis. Patulin was detected with a photodiode array detector at 273 nm. The standard curve was linear (r(2) = 0.9984) from 75 microgram/L to 121 microgram/mL with patulin working solutions corresponding to 3.8 microgram/L to 6.1 microgram/mL patulin in the sample. The linearity was better in a narrower range of concentrations (r(2) = 0.9999) from 75 microgram/L to 24.1 microgram/mL. The limit of detection of the method was 3.8 microgram/L. Patulin recoveries at 4 levels in spiked samples (10-121 microgram/L) ranged from 95.2 to 105.4%. The recoveries were 96. 9% and 99.2% for 2 levels (22.3 and 223 microgram/L, respectively) of patulin in infected apple samples. This method represents a unique alternative method for rapid and sensitive analysis of patulin in apple ciders.  相似文献   

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