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Evaluation of a solid-phase extraction system for determining pesticide residues in milk. 固相萃取法测定牛奶中农药残留的评价。
Journal of chromatography Pub Date : 1993-07-16 DOI: 10.1016/0021-9673(93)80087-o
J Mañes, G Font, Y Picó
{"title":"Evaluation of a solid-phase extraction system for determining pesticide residues in milk.","authors":"J Mañes,&nbsp;G Font,&nbsp;Y Picó","doi":"10.1016/0021-9673(93)80087-o","DOIUrl":"https://doi.org/10.1016/0021-9673(93)80087-o","url":null,"abstract":"<p><p>A simple and rapid procedure based on reversed solid-phase extraction with octadecylsilica was developed for determining chlorinated pesticide residues in milk. The need for an agent that breaks the fat globules was first investigated and the method variables were optimized on whole homogenized milk (3.6% fat content). Recovery experiments performed for 26 organochlorine pesticides at levels of 3-40 micrograms/l gave > 80% recoveries for all the compounds. The method was validated and evaluated by comparison with two widely used liquid-liquid extraction methods. The performance was checked by analysis of a certified standard with natural low endogenous levels (CMR 187) and different kinds of milk (skimmed, 2%, powdered, evaporated and condensed) spiked with the 26 pesticides. The procedure was used to analyse 45 commercial milks in which the presence of organochlorine residues had been detected. The proposed method offers advantages such as low cost and simplicity and the fact that the extracts obtained do not require a purification step.</p>","PeriodicalId":15508,"journal":{"name":"Journal of chromatography","volume":"642 1-2","pages":"195-204"},"PeriodicalIF":0.0,"publicationDate":"1993-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0021-9673(93)80087-o","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19352178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 25
Characterization of each isoform of a F(ab')2 by capillary electrophoresis. 毛细管电泳表征F(ab')2的各亚型。
Journal of chromatography Pub Date : 1993-07-09 DOI: 10.1016/0021-9673(93)80155-2
R Vincentelli, N Bihoreau
{"title":"Characterization of each isoform of a F(ab')2 by capillary electrophoresis.","authors":"R Vincentelli,&nbsp;N Bihoreau","doi":"10.1016/0021-9673(93)80155-2","DOIUrl":"https://doi.org/10.1016/0021-9673(93)80155-2","url":null,"abstract":"<p><p>Free solution capillary electrophoresis was investigated for the characterization of an M(r) 100 000 purified F(ab')2. Optimization of the experimental conditions allowed the identification of five separated peaks, suggesting the presence of isoforms which differed by only 0.2 pH unit. This heterogeneity was still detectable with 80 amol of protein. After a preparative separation by chromatofocusing, identification of each form was performed for the first time by capillary electrophoresis. A quantitative and qualitative correlation with isoelectric focusing showed that free solution capillary electrophoresis represents a sensitive method for revealing subtle differences in charge, even for large proteins.</p>","PeriodicalId":15508,"journal":{"name":"Journal of chromatography","volume":"641 2","pages":"383-90"},"PeriodicalIF":0.0,"publicationDate":"1993-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0021-9673(93)80155-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21330068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 9
Enantiomeric separation of fluorescent, 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate, tagged amino acids. 6-氨基喹啉- n -羟基琥珀酰氨基氨基甲酸酯标记氨基酸的荧光对映体分离。
Journal of chromatography Pub Date : 1993-07-09 DOI: 10.1016/0021-9673(93)80142-u
M Pawlowska, S Chen, D W Armstrong
{"title":"Enantiomeric separation of fluorescent, 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate, tagged amino acids.","authors":"M Pawlowska,&nbsp;S Chen,&nbsp;D W Armstrong","doi":"10.1016/0021-9673(93)80142-u","DOIUrl":"https://doi.org/10.1016/0021-9673(93)80142-u","url":null,"abstract":"<p><p>A new derivatizing reagent, 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC), has been used successfully for chromatographic enantioseparation of 31 amino acids on cyclodextrin bonded stationary phases. AQC reacts with both primary and secondary amino acids to produce stable and highly fluorescent derivatives suitable for efficient and sensitive chromatographic determinations. The derivatization reaction proceeds without detectable racemization. The detection limit is in the femtomole range and approximately 0.0075% of the D-enantiomer in an excess of the L-enantiomer is detectable. High resolution values are needed when determining trace enantiomeric impurities.</p>","PeriodicalId":15508,"journal":{"name":"Journal of chromatography","volume":"641 2","pages":"257-65"},"PeriodicalIF":0.0,"publicationDate":"1993-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0021-9673(93)80142-u","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19352173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Comparison of flame ionization and inductively coupled plasma mass spectrometry for the detection of organometallics separated by capillary supercritical fluid chromatography. 火焰电离与电感耦合等离子体质谱法检测毛细管超临界流体色谱分离的有机金属。
Journal of chromatography Pub Date : 1993-07-09 DOI: 10.1016/0021-9673(93)80150-7
N P Vela, J A Caruso
{"title":"Comparison of flame ionization and inductively coupled plasma mass spectrometry for the detection of organometallics separated by capillary supercritical fluid chromatography.","authors":"N P Vela,&nbsp;J A Caruso","doi":"10.1016/0021-9673(93)80150-7","DOIUrl":"https://doi.org/10.1016/0021-9673(93)80150-7","url":null,"abstract":"<p><p>Organotin compounds are separated by capillary supercritical fluid chromatography (SFC) and a comparison of the detection by flame ionization (FID) and inductively coupled plasma mass spectrometry (ICP-MS) is presented. Resolution, detection limits, linear dynamic range and reproducibility are the parameters compared between SFC-FID and SFC-ICP-MS, for the detection of tri- and tetraorganotin compounds. The resolution obtained in the SFC-FID system is not always observed in SFC-ICP-MS. Degradation in resolution is due to fluctuations in transfer line temperature. Baseline resolution for the organotins considered is achieved in both systems by using a longer column. Detection limits (DLs) are calculated as 3 sigma/S, where sigma is the standard deviation of the blank signal and S is the slope of the calibration curve. Detection limits of 10.3, 12.5, 12.0 and 9.0 pg are obtained for tetrabutyltin, tributyltin chloride, triphenyltin chloride and tetraphenyltin, respectively, using SFC-FID. An improvement in detection limits of one order of magnitude is achieved by SFC-ICP-MS for the same organotins (0.26, 0.80, 0.57 and 0.20 pg, respectively). The relative standard deviations using SFC-FID for five 50-nl injections, containing 0.5 ng Sn, ranged from 3.2 to 6.4%. Using SFC-ICP-MS, five replicate injections of 0.05 ng Sn give R.S.D.s from 1.3 to 3.4%.</p>","PeriodicalId":15508,"journal":{"name":"Journal of chromatography","volume":"641 2","pages":"337-45"},"PeriodicalIF":0.0,"publicationDate":"1993-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0021-9673(93)80150-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19352174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 25
4-(Trifluoromethyl)-2,3,5,6-tetrafluorobenzyl bromide as a new electrophoric derivatizing reagent. 4-(三氟甲基)-2,3,5,6-四氟苯溴作为一种新的电泳衍生试剂。
Journal of chromatography Pub Date : 1993-07-09 DOI: 10.1016/0021-9673(93)80158-5
M Saha, J Saha, R W Giese
{"title":"4-(Trifluoromethyl)-2,3,5,6-tetrafluorobenzyl bromide as a new electrophoric derivatizing reagent.","authors":"M Saha,&nbsp;J Saha,&nbsp;R W Giese","doi":"10.1016/0021-9673(93)80158-5","DOIUrl":"https://doi.org/10.1016/0021-9673(93)80158-5","url":null,"abstract":"<p><p>4-(Trifluoromethyl)-2,3,5,6-tetrafluorobenzyl bromide (TTBB) was synthesized in a single step from alpha,alpha,alpha,2,3,5,6-heptafluoro-p-xylene. The purpose of TTBB is to function as an analogue of pentafluorobenzyl bromide (PFBB) in electrophoric derivatization reactions prior to detection by gas chromatography-electron-capture negative ion mass spectrometry (GC-ECNI-MS). In more detail, it was anticipated that TTBB could be used along with, or as a substitute for, PFBB to help control some interferences and confirm results. This is because a TTBB-product (of an analyte) would have different retention and sometimes m/z characteristics than a corresponding PFBB product in GC-ECNI-MS, while the two products should be similar in their ease of formation and yields. Results demonstrating these expectations were achieved by derivatizing and detecting two analytes with these reagents: N7-(2-hydroxyethyl)xanthine, and 2,3-pyrenedicarboxylic acid.</p>","PeriodicalId":15508,"journal":{"name":"Journal of chromatography","volume":"641 2","pages":"400-4"},"PeriodicalIF":0.0,"publicationDate":"1993-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0021-9673(93)80158-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19352175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 11
Analytical gel filtration of dextran for the study of the glomerular barrier function. 右旋糖酐的分析凝胶过滤研究肾小球屏障功能。
Journal of chromatography Pub Date : 1993-07-02 DOI: 10.1016/0021-9673(93)83459-6
L Hagel, A Hartmann, K Lund
{"title":"Analytical gel filtration of dextran for the study of the glomerular barrier function.","authors":"L Hagel,&nbsp;A Hartmann,&nbsp;K Lund","doi":"10.1016/0021-9673(93)83459-6","DOIUrl":"https://doi.org/10.1016/0021-9673(93)83459-6","url":null,"abstract":"<p><p>Analytical gel filtration was used for the study of molecular size distribution of clinical dextran in serum and urine for the purpose of evaluations of changes in the human glomerular barrier function. The column was calibrated in terms of solute size using a simple and accurate technique recently described. Only one sample of a dextran possessing a broad molecular mass distribution was necessary for the calibration procedure and the calculations were performed using an ordinary spreadsheet. The accuracy of the calibration, as evaluated by protein samples, is better than 95%. The simplicity makes the method suitable for use in laboratories not normally specializing in analytical gel filtration. Calibration in terms of size is preferably done with respect to viscosity radius to obtain relevant information about the permeability of dextran into porous membranes.</p>","PeriodicalId":15508,"journal":{"name":"Journal of chromatography","volume":"641 1","pages":"63-70"},"PeriodicalIF":0.0,"publicationDate":"1993-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0021-9673(93)83459-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18691541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 10
Shape-selective separation of polycyclic aromatic hydrocarbons by reversed-phase liquid chromatography on tetraphenylporphyrin-based stationary phases. 四苯基卟啉固定相反相液相色谱法分离多环芳烃。
Journal of chromatography Pub Date : 1993-07-02 DOI: 10.1016/0021-9673(93)83457-4
C E Kibbey, M E Meyerhoff
{"title":"Shape-selective separation of polycyclic aromatic hydrocarbons by reversed-phase liquid chromatography on tetraphenylporphyrin-based stationary phases.","authors":"C E Kibbey,&nbsp;M E Meyerhoff","doi":"10.1016/0021-9673(93)83457-4","DOIUrl":"https://doi.org/10.1016/0021-9673(93)83457-4","url":null,"abstract":"<p><p>The reversed-phase chromatographic behavior of planar and non-planar polycyclic aromatic hydrocarbons (PAHs) is investigated on tetraphenylporphyrin and two metallotetraphenylporphyrin [Sn(IV), In(III)] bonded stationary phases using methanol-water and acetonitrile-water as mixed solvent mobile phases. Large differences in the capacity factors of aromatic solute pairs having the same number of carbon atoms, but differing in three-dimensional shape (e.g., triphenylene/o-terphenyl and perylene/alpha, alpha'-binaphthyl), suggest that the three tetraphenylporphyrin-based supports possess shape selectivity toward small planar aromatic solutes. Capacity factors for planar PAH solutes on these supports are significantly greater than for non-planar polyaryls having the same number of carbon atoms.</p>","PeriodicalId":15508,"journal":{"name":"Journal of chromatography","volume":"641 1","pages":"49-55"},"PeriodicalIF":0.0,"publicationDate":"1993-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0021-9673(93)83457-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19335124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 43
Methionine enkephalin-like immunoreactivity, substance P-like immunoreactivity and beta-endorphin-like immunoreactivity post-mortem stability in rat pituitary. 蛋氨酸脑啡肽样免疫反应性、p物质样免疫反应性和-内啡肽样免疫反应性对大鼠垂体死后稳定性的影响。
Journal of chromatography Pub Date : 1993-07-02
X Zhu, D M Desiderio
{"title":"Methionine enkephalin-like immunoreactivity, substance P-like immunoreactivity and beta-endorphin-like immunoreactivity post-mortem stability in rat pituitary.","authors":"X Zhu,&nbsp;D M Desiderio","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Significant post-mortem changes in peptide concentration occur within the previously unstudied timeframe, i.e. within 1 h, for the proenkephalin A, proopiomelanoccortin, and tachykinin neuropeptidergic systems in the pituitary. These data differ from data obtained in other studies that concluded that peptides are stable for up to 72 h post-mortem. The post-mortem stability of the three neuropeptides, methionine enkephalin, substance P, and beta-endorphin, was studied in the rat pituitary to test the hypothesis that significant post-mortem concentration changes of those three neuropeptides occur in the immediate post-mortem time period.</p>","PeriodicalId":15508,"journal":{"name":"Journal of chromatography","volume":"616 2","pages":"175-87"},"PeriodicalIF":0.0,"publicationDate":"1993-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18693979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Analysis of cationic nutrients from foods by ion chromatography. 离子色谱法分析食品中阳离子营养素。
Journal of chromatography Pub Date : 1993-06-25 DOI: 10.1016/0021-9673(93)80203-k
J Morawski, P Alden, A Sims
{"title":"Analysis of cationic nutrients from foods by ion chromatography.","authors":"J Morawski,&nbsp;P Alden,&nbsp;A Sims","doi":"10.1016/0021-9673(93)80203-k","DOIUrl":"https://doi.org/10.1016/0021-9673(93)80203-k","url":null,"abstract":"<p><p>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.</p>","PeriodicalId":15508,"journal":{"name":"Journal of chromatography","volume":"640 1-2","pages":"359-64"},"PeriodicalIF":0.0,"publicationDate":"1993-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0021-9673(93)80203-k","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19332394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 29
Effect of temperature on the salt balance of milk studied by capillary ion electrophoresis. 用毛细管离子电泳法研究了温度对牛奶盐平衡的影响。
Journal of chromatography Pub Date : 1993-06-25 DOI: 10.1016/0021-9673(93)80211-p
M Schmitt, F Saulnier, L Malhautier, G Linden
{"title":"Effect of temperature on the salt balance of milk studied by capillary ion electrophoresis.","authors":"M Schmitt,&nbsp;F Saulnier,&nbsp;L Malhautier,&nbsp;G Linden","doi":"10.1016/0021-9673(93)80211-p","DOIUrl":"https://doi.org/10.1016/0021-9673(93)80211-p","url":null,"abstract":"<p><p>Many inorganic species, such as calcium, phosphate and magnesium, are in equilibrium between the liquid and colloidal phases of milk and hence are of importance with respect to the coagulation properties of milk. Capillary ion electrophoresis makes possible the determination of anions and cations in less than 6 min. The soluble phase of milk was obtained by ultrafiltration and samples had to be diluted 250-fold before analysis. Cold storage increased soluble calcium and phosphate concentrations, and warm-up of the milk restored the initial ionic equilibria. More drastic heat treatments (80-90 degrees C) caused precipitation of tricalcium phosphate and calcium citrate.</p>","PeriodicalId":15508,"journal":{"name":"Journal of chromatography","volume":"640 1-2","pages":"419-24"},"PeriodicalIF":0.0,"publicationDate":"1993-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0021-9673(93)80211-p","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19331632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 33
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