Home About us Contact
|
Home About us Contact | ||
|
|
||
Recovery
Kinds of Recovery Terms modified by Recovery Selected AbstractsWHY IS NATURAL RECOVERY SO COMMON FOR ADDICTIVE DISORDERS?ADDICTION, Issue 9 2010WENDY S. SLUTSKE No abstract is available for this article. [source] ALCOHOL PROBLEMS IN NATIVE AMERICA: THE UNTOLD STORY OF THE RESISTANCE AND RECOVERY,THE TRUTH ABOUT THE LIEADDICTION, Issue 1 2007JOSEPH WESTERMEYER No abstract is available for this article. [source] IMPROVEMENT OF HEART RATE RECOVERY AFTER EXERCISE TRAINING IN OLDER PEOPLEJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 11 2005Francesco Giallauria MD No abstract is available for this article. [source] EFFECT OF SALTS AND POLYETHYLENE GLYCOLS ON THE PARTITIONING AND RECOVERY OF TRYPSIN FROM HYBRID CATFISH VISCERA IN AQUEOUS TWO-PHASE SYSTEMSJOURNAL OF FOOD BIOCHEMISTRY, Issue 4 2010SAPPASITH KLOMKLAO ABSTRACT The partitioning behavior of trypsin from hybrid catfish viscera in aqueous two-phase systems (ATPS) was studied. Factors such as polyethylene glycol (PEG) molecular mass and concentration, as well as types and concentration of salts, affected protein separation. Trypsin partitioned mainly in the top PEG-rich phase. ATPS formed by PEG of molecular weight 4,000 (20%, w/w) and NaH2PO4 (20%, w/w) showed the best capability for trypsin purification from hybrid catfish viscera. Under such conditions, the highest specific activity (30.05 units/µg protein) and purification (27.3-fold), were obtained. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis revealed that the enzyme after ATPS separation was near homogeneity and based on the activity staining, the band intensity of enzyme in ATPS fraction increased, indicating the greater specific activity of the viscera extract. The partitioned enzyme displayed optimal activity at pH 9.0 and 50C, respectively. The enzyme was stable up to 40C and within the pH range of 8,12. The enzyme exhibited a progressive decrease in activity with increasing NaCl concentration. PRACTICAL APPLICATIONS This paper describes the separation and recovery of trypsin from hybrid catfish viscera in ATPS and its properties. ATPS provides an efficient and attractive method for partitioning and recovery of trypsin from hybrid catfish viscera. Trypsins from various sources catalyze the hydrolysis of peptide bonds on the carboxyl sides of arginine and lysine. Therefore, it is expected that like other trypsins, trypsin after ATPS separation from hybrid catfish viscera could be useful in the biomedical, food and beverage industries. [source] RECOVERY OF SINAPIC ACID FROM A WASTE STREAM IN THE PROCESSING OF YELLOW MUSTARD PROTEIN ISOLATEJOURNAL OF FOOD PROCESS ENGINEERING, Issue 2 2008N. PRAPAKORNWIRIYA ABSTRACT A large amount of waste permeates generated from the processing of yellow mustard protein was concentrated fivefold using a nanofilter with a molecular weight cut off of 1,000 Da, while approximately 74% of sinapic acid was retained. Sinapic acid was then released from sinapine, its esterified form, by an alkaline hydrolysis. The hydrolyzed solution was acidified to prevent oxidation of the sinapic acid and to precipitate the remaining proteins. Subsequently, sinapic acid and other phenolics were extracted by a two-stage extraction using a mixture of diethyl ether and ethyl acetate (1:1), 165-min extraction time and permeate-to-solvent ratio of 1:2. Approximately 95% of the sinapic acid in the acidified permeate was finally concentrated in the solvent phase. PRACTICAL APPLICATIONS This development has led to an economical process to recover phenolics and to treat effluent from a process of oilseed protein while reducing the use of water during the extraction of protein. A reduction of water usage makes the processing of oilseed protein isolate more economically attractive, and the recovered phenolics may find a use as a nutraceutical. The developed process is not only limited to the recovery of phenolics from mustard, but also applied for recovering phenolic acids, specifically sinapic acid, from waste water from membrane processing of protein from mustard and similar polyphenol-containing oilseeds. [source] COMPARATIVE STUDY OF SHELL SWAB AND SHELL CRUSH METHODS FOR THE RECOVERY OF SALMONELLA FROM SHELL EGGSJOURNAL OF FOOD SAFETY, Issue 4 2008T. KAWASAKI ABSTRACT Swabbing is the standard methodology for the recovery of resident microorganism from shell eggs in Japan. A comparative study of shell swab (SW) and shell crush (CR) techniques was performed to recover the laboratory-inoculated Salmonella from shell eggs. It was found that the recovery of Salmonella by CR methods was significantly higher (4.5,7.5 log cfu/egg) than that of SW methods (3.1,6.3 log cfu/egg). However, analyses with quantitative real-time polymerase chain reaction (invA as a target gene), fluorescent microscopic and quantitative analyses with a Live/Dead BacLight bacterial viability kit revealed that not all of the inoculated Salmonella spp. populations were recovered as intact cells by either method. The chemiluminescent bacterial viability assay showed that chemiluminescence intensity (CI) began to increase after 30 min in CR samples; on the other hand, SW samples did not show any increase in CI for 2 h. These results suggest that SW might cause more damage and lethality to cells than CR. In addition, to determine the most appropriate method for recovering resident aerobic bacteria, coliforms and Salmonella spp from shell eggs, 4,000 commercial eggs were collected and sampled by shell rinse (SR) and CR techniques using phosphate-buffered saline (PBS) warmed to different temperatures. PBS at 37C was found to be the best recovery solution and temperature, respectively, for recovering aerobic microorganisms from shell eggs by both methods and the CR methods recovered a higher population than did the SR methods (4.9 versus 5.8 log cfu/egg for SR and CR methods, respectively; n = 500 eggs/method). Therefore, the CR method along with recovery buffer (PBS) at 37C could be an effective technique for the recovery of microorganisms from post-processed shell eggs. PRACTICAL APPLICATIONS There is a need to develop a rapid and highly sensitive method for the recovery of microorganisms from shell eggs. Such recovery methods are also useful for evaluating the efficacy of newly developed shell egg disinfection techniques. Many methods involving rinsing, swabbing, and crushing of shell eggs have been reported; however, we performed a comparative study of the method used to recover the Salmonella from shell eggs. We found that the shell crush method (CR) was superior to the shell swab method (SW) for the recovery of Salmonella spp., and phosphate-buffered saline (PBS) at 37C was found to be the best recovery solution and temperature, respectively, for recovering microorganisms from shell eggs by both methods. Therefore, the CR method along with recovery buffer (PBS) at 37C could be an effective technique for the recovery of microorganisms from post-processed shells. Use of this method could be recommended for the microbial evaluation of post-processed shell eggs in industries. [source] SIMULTANEOUS RECOVERY AND DETECTION OF FOUR HEAT-INJURED FOODBORNE PATHOGENS IN GROUND BEEF AND MILK BY A FOUR-COMPARTMENT THIN AGAR LAYER PLATEJOURNAL OF FOOD SAFETY, Issue 2 2006VIVIAN C.H. WU ABSTRACT A four-compartment thin agar layer (4-TAL) system was developed to improve operation efficiency and recover injured foodborne pathogens simultaneously. The system consisted of a layer of nonselective agar overlaid on four different selective agars (xylose lysine desoxycholate [XLD], cefsulodin irgasan novobiocin [CIN], modified Oxford medium [MOX] and MacConkey sorbitol agar [MSA]) housed in a four-compartment petri dish. We applied this system to simultaneously recover heat-injured (55C, 10 min) Escherichia coli O157:H7 (MSA), Listeria monocytogenes (MOX), Salmonella Typhimurium (XLD) and Yersinia enterocolitica (CIN) from ground beef and pasteurized milk. No significant difference (P > 0.05) occurred between the single recovery unit (nonselective agar overlaid on one selective agar in a standard petri dish) and the 4-TAL for detecting four heat-injured pathogens in tested samples. Both TAL methods showed greater recovery of four heat-injured pathogens than the pathogen-specific selective media (P < 0.05). The 4-TAL system appears to be efficient for recovery and detection of injured pathogens in food in terms of operation, material and labor costs, and space of incubation. [source] COUPLES THERAPY FOR WOMEN SURVIVORS OF CHILD SEXUAL ABUSE WHO ARE IN ADDICTIONS RECOVERY: A COMPARATIVE CASE STUDY OF TREATMENT PROCESS AND OUTCOMEJOURNAL OF MARITAL AND FAMILY THERAPY, Issue 1 2001Barry Trute Treatment for women who are survivors of child sexual abuse and who have a history of substance abuse has largely involved gender-specific interventions. This study examines the use of conjoint couple therapy with a cohort of women who were survivors of child sexual abuse and who are in addiction recovery and with their partners. A comparative case study analysis incorporated standardized clinical measures with client and therapist interviews. Brief conjoint therapy was found to assist couples in the specific relationship skill areas of communication and mutual problem solving. Further, substantive gains were found in the realm of affective relations. The women reported an increase in support from their male partners, and the men reported a decrease in negative emotional atmosphere in the relationship. [source] BIODEGRADATION OF DISINFECTION BYPRODUCTS AS A POTENTIAL REMOVAL PROCESS DURING AQUIFER STORAGE RECOVERY,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 4 2000James E. Landmeyer ABSTRACT: The biodegradation potential of two drinking water disinfection byproducts was investigated using aquifer materials obtained from approximately 100 and 200 meters below land surface in an aerobic aquifer system undergoing aquifer storage recovery of treated surface water. No significant biodegradation of a model trihalomethane compound, chloroform, was observed in aquifer microcosms under aerobic or anaerobic conditions. In contrast, between 16 and 27 percent mineralization of a radiolabeled model haloacetic acid compound, chloroacetic acid, was observed. These results indicate that although the potential for biodegradation of chloroacetic acid exists in deep aquifer systems, chloroform entrained within these aquifers or formed in situ will tend to persist. These results have important implications for water managers planning to meet anticipated lowered permissible levels of trihalomethanes in drinking water. [source] SENSATION RECOVERY IMPROVED BY GREAT AURICULAR NERVE PRESERVATION IN PAROTIDECTOMY: A PROSPECTIVE DOUBLE-BLIND STUDYANZ JOURNAL OF SURGERY, Issue 5 2007Dacita T. K. Suen Background: The great auricular nerve (GAN) is frequently sacrificed during parotidectomy and causes sensory disturbance of the auricle. Our study is to investigate whether GAN preservation can improve the sensory recovery. Methods: Patients undergoing superficial or total conservative parotidectomy for benign tumours were recruited consecutively from November 1998 to September 2001. Different sensory methods (light touch, two-point discrimination and sharp pain) of the auricle were evaluated by a designated physiotherapist preoperatively as well as at 1, 3, 6 and 12 months postoperatively. The patients and the physiotherapist were blinded to the integrity of the GAN. Long-term subjective assessment was also carried out beyond 2 years postoperatively. Results: A total of 21 patients were recruited for the study. GAN were preserved in 10 patients. The mean follow up was 16 months (12,42 months). There was no difference in sex distribution, type of operation and pathology of parotid tumour between the two groups. No postoperative mortality occurred and postoperative morbidity did not differ between the two groups. Patients with GAN preserved had significantly better light touch and sharp pain recovery at 1 year postoperatively. Subjective assessment of sensory dysfunction also favoured GAN preservation. Conclusion: Great auricular nerve preservation minimizes the postoperative sensory disturbance and should be considered whenever tumour clearance is not compromised. [source] DNA AND PROTEIN RECOVERY FROM WASHED EXPERIMENTAL STONE TOOLS,ARCHAEOMETRY, Issue 4 2004O. C. SHANKS Traces of protein and DNA are preserved on stone tools used to process animals. Previous research documents the identification of protein residues from tools sonicated in 5% ammonium hydroxide, but it remains untested whether the same treatment yields useable DNA. In this study we report both DNA and protein recovery using 5% ammonium hydroxide from residues on stone tools. We extracted 13-year-old residues from experimentally manufactured stone tools used to butcher a single animal. We also show that surface washing procedures typically used to curate stone tools remove only a small fraction of the DNA and protein deposited during animal butchery. [source] RECOVERY FROM DEPRESSION: AUSTRALIA IN AN ARGENTINE MIRROR 1895,1913AUSTRALIAN ECONOMIC HISTORY REVIEW, Issue 3 2006Article first published online: 20 OCT 200, Ian W. McLean Argentina; Australia; debt crisis; recovery policies The recovery from the 1890s depression in Australia was prolonged, and economic growth from 1895 to 1913 was below that in the comparable settler economies of Argentina and Canada. Why? Australia's hesitant initial recovery is typically attributed to the imbalances in the economy resulting from the preceding boom, and its further delay to severe drought. Drawing on Argentine experience, it is suggested that additional factors need to be considered. Unlike Argentina, the unwillingness or inability of Australian governments to reschedule foreign debt or devalue the exchange rate exacerbated the slump. And the era of low-cost pioneer farming ended earlier than in Argentina (or Canada). [source] THERAPY AS MEMORY-WORK: DILEMMAS OF DISCOVERY, RECOVERY AND CONSTRUCTIONBRITISH JOURNAL OF PSYCHOTHERAPY, Issue 4 2002Erica Burman ABSTRACT In this paper I have sought to shift the focus on the construction of memory within psychotherapeutic practice in a number of different directions to draw some more general lessons for the process and status of therapeutic accounts. The precipitating context for the current scrutiny of memory-making within therapy may have limited its scope and fruitfulness. The fact that this issue was largely prompted by debates about the status of (usually) adult women's recovery of memories of early abuse within therapy is a relevant factor that has been compounded by issues of professional credibility and hierarchy. Clearly, at a cultural level, women's memories of childhood abuse function politically as well as personally, as reflected by the social and legal responses to this challenge. However, guidelines for professional practice cannot legislate for the indeterminacies surrounding the subjectivity of memory, while assumptions underlying the empirical psychological resources drawn upon to inform debates in psychotherapy require critical scrutiny. Clinical and interpretive dilemmas extend beyond the status accorded client memorial reports to therapists' memory-making practices as textualized via both supervision and clinical notetaking. Drawing on more recent (including feminist) discussions of memory that identify different political possibilities within third and first person accounts it was suggested that, rather than eschewing the subjectivity of memory, therapists can instead analyse this as a key interpretive and reflexive resource to inform their own practice. [source] Novel Potentiometric Sensors of Molecular Imprinted Polymers for Specific Binding of ChlormequatELECTROANALYSIS, Issue 2 2008Ayman Abstract Molecularly imprinted polymers (MIP) were used as potentiometric sensors for the selective recognition and determination of chlormequat (CMQ). They were produced after radical polymerization of 4-vinyl pyridine (4-VP) or methacrylic acid (MAA) monomers in the presence of a cross-linker. CMQ was used as template. Similar non-imprinted (NI) polymers (NIP) were produced by removing the template from reaction media. The effect of kind and amount of MIP or NIP sensors on the potentiometric behavior was investigated. Main analytical features were evaluated in steady and flow modes of operation. The sensor MIP/4-VP exhibited the best performance, presenting fast near-Nernstian response for CMQ over the concentration range 6.2×10,6,1.0×10,2,mol L,1 with detection limits of 4.1×10,6,mol L,1. The sensor was independent from the pH of test solutions in the range 5,10. Potentiometric selectivity coefficients of the proposed sensors were evaluated over several inorganic and organic cations. Results pointed out a good selectivity to CMQ. The sensor was applied to the potentiometric determination of CMQ in commercial phytopharmaceuticals and spiked water samples. Recoveries ranged 96 to 108.5%. [source] Voltametric and Flow Injection Determination of Oxytetracycline Residues in Food Samples Using Carbon Fiber MicroelectrodesELECTROANALYSIS, Issue 7 2003L. Agüí Abstract A voltammetric method for the determination of the antibiotic oxytetracycline (OTC) in food samples is reported. Carbon fiber microelectrodes (CFMEs), which allow voltammetric measurements to be performed in a small volume (1,mL) of the analyte extract from the samples, are employed. Repeatable electroanalytical responses were obtained with no need of applying cleaning treatments to the CFME. Under the optimized square-wave conditions, a linear calibration plot for OTC was obtained in the 1.0×10,6,1.0×10,4,mol,L,1 range, with a detection limit of 2.9×10,7,mol,L,1 (150,ng,mL,1) OTC. The determination of OTC by a flow-injection method with amperometric detection using a homemade flow cell specially designed to work with CFMEs, was also evaluated using pure acetonitrile as the carrier. The SW voltammetric method was applied to the determination of OTC in spiked milk and eggs samples, at 100,ng,mL,1 and 200,ng g,1 levels, respectively. The procedure involved the extraction of the analyte in ethyl acetate, evaporation of the solvent and reconstitution of the residue in acetonitrile ,5.0×10,4,mol,L,1 tetrabutylammonium perchlorate medium. Recoveries of 96±8 and 91±8% were obtained for milk and eggs, respectively, by applying the standard additions method. [source] Separation and determination of carnosine-related peptides using capillary electrophoresis with laser-induced fluorescence detectionELECTROPHORESIS, Issue 3 2005Ying Huang Abstract A capillary electrophoresis (CE) method with laser-induced fluorescence (LIF) detection was developed for the separation and detection of carnosine-related peptides (carnosine, anserine, and homocarnosine). A sensitive and fluorogenic regent, 3-(4-carboxybenzoyl) quinoline-2-carboxaldehyde (CBQCA) was selected as a precapillary labeling reagent for imidazole dipeptides to form isoindole derivatives. The optimized molar ratio between CBQCA and peptide was found to be 75:1, and 50 mmol/L borate buffer (pH 9.2) was used for the derivatization in order to achieve good efficiency. Three imidazole dipeptides were baseline-separated within 20 min by using 112 mmol/L sodium borate (pH 10.4,10.8) as running buffer. Concentration detection limits (signal-to-noise ratios) for carnosine, anserine, and homocarnosine were 4.73, 4.37, and 3.94 nmol/L, respectively. This method has been applied to the analysis of human cerebrospinal fluid (CSF) and meat dry powder of pig and sheep. Recoveries were in the range of 82.9,104.8% for homocarnosine in CSF. For carnosine and anserine, the recoveries are 98.3% and 80.2% in meat dry powder of pig and 111.2% and 112.8% in meat dry powder of sheep, respectively. [source] A systematic investigation into the recovery of radioactively labeled proteins from sodium dodecyl sulfate-polyacrylamide gelsELECTROPHORESIS, Issue 1 2004Shaobo Zhou Abstract We report the results of a systematic investigation designed to optimize a method for quantifying radioactivity in proteins in sodium dodecyl sulfate-polyacrylamide gels. The method involves dissolving appropriately sized pieces of gel in hydrogen peroxide and heating to 70°C overnight followed by liquid scintillation counting. H2O2 had no effect on the count rates of [14C]bovine serum albumin (BSA) when counted in a conventional liquid scintillation system, and the count rates remained stable for several days. Temperatures below 70°C resulted in incomplete extraction of radioactivity from gels containing [14C]BSA, but there was also a significant reduction in count rates in samples incubated at 80°C. At 70°C recovery was not affected by the amount of sample loaded onto the gel or by the staining procedure (Coomassie Brilliant Blue or SYPRO Ruby). Recoveries were in the range of 89,94%, and the coefficient of variation for five replicate samples was 5,10%. This method offers a reliable way of measuring the amount of radioactivity in proteins that have been separated by electrophoresis. It may be useful, for example, in quantitative metabolic labeling experiments when it is necessary to know precisely how much tracer has been incorporated into a particular protein. [source] Fluorescence polarization immunoassay based on a monoclonal antibody for the detection of ochratoxin AINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 8 2004Won-Bo Shim Summary A fluorescence polarization immunoassay (FPIA) based on a monoclonal antibody for the determination of ochratoxin A (OTA) was developed. Fluorescein-labelled OTA derivative (tracer) was synthesized and purified by thin-layer chromatography. The optimized OTA FPIA had a dynamic range from 5 to 200 ng mL,1 with IC50 value of 30 ng mL,1 and a detection limit of 3 ng mL,1. The method developed was characterized by high specificity and reproducibility. Cross-reactivity with other mycotoxins (zearalenone, aflatoxins, patulin and T-2 toxin) was negligible (<0.1%). Methanol extracts of barley samples were used for the analysis. The results of OTA determination in barley were compared with those determined by indirect competitive enzyme-linked immunosorbent assay (ELISA). Recoveries for the samples spiked at 50, 100 and 500 ng g,1 levels were 91, 90 and 97%, respectively, for FPIA, and 98, 98 and 102%, for ELISA. Naturally contaminated barley samples were analysed by these methods but some disagreement was observed between the results. The FPIA method can be applied for screening of food samples for OTA residues without a complicated clean-up. [source] High-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry for the determination of flocoumafen and brodifacoum in whole bloodJOURNAL OF APPLIED TOXICOLOGY, Issue 1 2007Mi-cong Jin Abstract A high-performance liquid chromatographic,tandem mass spectrometric (HPLC,MS,MS) assay was developed and validated to determine quantitatively flocoumafen and brodifacoum in whole blood using warfarin as an internal standard (IS). Liquid,liquid extraction, using ethyl acetate, was used to isolate flocoumafen, brodifacoum and the IS from the biological matrix. Detection was performed on a mass spectrometer by negative electrospray ionization (ESI) in multiple reaction monitoring (MRM) mode. The calibration curves were linear (r2 > 0.998) in the concentration range of 0.1,100.0 ng ml,1 with a lower limit of quantification of 0.05 ng ml,1 for flocoumafen, and 0.1 ng ml,1 for brodifacoum in whole blood. Intra-day and inter-day relative standard deviations (RSDs) were less than 8.0% and 10.8%, respectively. Recoveries of flocoumafen and brodifacoum ranged from 78.0% to 83.7%. This assay can be used to determine trace flocoumafen and brodifacoum in whole blood to investigate suspected poisoning of human and animals. Copyright © 2006 John Wiley & Sons, Ltd. [source] Factors influencing the occurrence of entomopathogenic nematodes in the Central Rift Valley Region of KenyaAFRICAN JOURNAL OF ECOLOGY, Issue 2008S. W. Mwaniki Abstract A survey for entomopathogenic nematodes in the central Rift valley region of Kenya was conducted at altitudes between 1800 and 3000 m above sea level and from croplands and noncropland habitats. The sampling depth was 0,30 cm. GPS (global positioning system) was used to measure site positions. One hundred and twelve soil samples were collected and entomopathogenic nematodes trapped through Galleria mellonella. Entomopathogenic nematode presence was demonstrated by G. mellonella mortality and viable ones bulked through the same host. Nematode recoveries from two consecutive extractions were 30% per extraction and 52% for cumulative extractions. Recoveries from agro ecological zones ranged between 18% and 71%. Recovery frequency was higher from disturbed cropland habitats than the stable noncrop habitats. Steinernema species were more frequent than Heterorhabditis (9 : 1). Nematode occurrence clustered at 2,3% carbon and pH 5.3,6.3 with no specific pattern demonstrated from soil types. Nematode species of the two genera from high altitudes lost their culturing ability within 1 month of isolation. There was a tendency for recovering both nematode genera at the shores of water bodies. This is the first report of Steinernema yirgalemense and S. weiseri in Kenya and of S. karii in the central Rift valley region. The Heterorhabditis species has not been confirmed yet. This has widened the genetic base of entomopathogenic nematodes from Kenya. The entomopathogenic nematodes are available for developement as biological control agents of athropod pests. [source] Single Laboratory Method Performance Evaluation for the Analysis of Total Food Folate by Trienzyme Extraction and Microplate AssayJOURNAL OF FOOD SCIENCE, Issue 5 2007L. Chen ABSTRACT:, Single laboratory method performance parameters, including the calibration curve, accuracy, recovery, precision, limit of detection (LOD), and limit of quantification (LOQ), were evaluated for the analysis of total food folate by the trienzyme extraction and microplate assay with Lactobacillus casei subsp. rhamnosus. Standard Reference Material (SRM) 1546 (meat homogenate), SRM 2383 (baby food composite), SRM 1846 (infant formula), Certified Reference Material (CRM) 121 (wholemeal flour), and CRM 485 (mixed vegetables), representing a broad selection of food matrices, were used to evaluate the performance of the method. A generated 4-parameter logistic equation of the calibration curve was y= (0.0705 , 1.0396)/(1 + (x/0.0165) 1.3072) + 1.0396 (P < 0.0001). The test of parallelism demonstrated that matrix components in the food extracts did not affect the accuracy. Measured values of the SRMs and CRMs were within their certified or reference values. Recoveries for all reference materials met the requirements of the AOAC guidelines for single laboratory validation. Precision measured as repeatability, including simultaneous and consecutive replicates for each SRM and CRM, met the Horwitz criterion. LOD and LOQ values were 0.3 and 0.6 ,g/100 g, respectively. The results showed that trienzyme digestion using ,-amylase, PronaseR, and conjugase from chicken pancreas coupled with a 96-well microplate assay provided a highly accurate, reproducible, and sensitive method for the determination of folate in a variety of foods. [source] Optimization of the ESI and APCI experimental variables for the LC/MS determination of s-triazines, methylcarbamates, organophosphorous, benzimidazoles, carboxamide and phenylurea compounds in orange samplesJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 10 2007Guilherme M. Titato Abstract In this work, ten selected pesticides of different chemical groups, indicated to orange culture, were extracted and determined by liquid chromatography,mass spectrometry using both electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) operating in the positive ion detection mode. Applying a variables selection technique verified that cone voltage, source temperature and drying-gas flow-rate are the critical variables when the ESI was used, while cone voltage was found to be the only critical variable for the MS system, operating with the APCI ionization mode. After optimization of the most important parameters through the variables selection technique, the selected ion-recording (SIR) mode, monitoring the [M + H]+ species for all the compounds, was applied for the method validation of the pesticides, in both ionization modes. In orange samples, matrix effects did not interfere with the determination of the pesticides. Pesticides quantification limits ranged from 10 to 50 µg kg,1 for ESI and from 8.2 to 45 µg kg,1 for APCI. Linearity was studied from LOQ upto 200 times LOQ values (r > 0.98). Recoveries obtained were in the range of 70.2,100.5% (RSDs less than 10%). In order to guarantee that the identification and confirmation of the studied pesticides in real samples were unequivocal, characteristic fragment ions of the pesticides were obtained by varying the cone voltage (in-source CID). Copyright © 2007 John Wiley & Sons, Ltd. [source] A validated method for the determination of nicotine, cotinine, trans -3,-hydroxycotinine, and norcotinine in human plasma using solid-phase extraction and liquid chromatography-atmospheric pressure chemical ionization-mass spectrometryJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 6 2006Insook Kim Abstract A liquid chromatographic-mass spectrometric method for the simultaneous determination of nicotine, cotinine, trans -3,-hydroxycotinine, and norcotinine in human plasma was developed and validated. Analytes and deuterated internal standards were extracted from human plasma using solid-phase extraction and analyzed by liquid chromatography/atmospheric pressure chemical ionization-mass spectrometric detection with selected ion monitoring (SIM). Limits of detection and quantification were 1.0 and 2.5 ng/ml, respectively, for all analytes. Linearity ranged from 2.5 to 500 ng/ml of human plasma using a weighting factor of 1/x; correlation coefficients for the calibration curves were > 0.99. Intra- and inter-assay precision and accuracy were < 15.0%. Recoveries were 108.2,110.8% nicotine, 95.8,108.7% cotinine, 90.5,99.5% trans -3,-hydroxycotinine, and 99.5,109.5% norcotinine. The method was also partially validated in bovine serum, owing to the difficulty of obtaining nicotine-free human plasma for the preparation of calibrators and quality control (QC) samples. This method proved to be robust and accurate for the quantification of nicotine, cotinine, trans -3,-hydroxycotinine, and norcotinine in human plasma collected in clinical studies of acute nicotine effects on brain activity and on the development of neonates of maternal smokers. Copyright © 2006 John Wiley & Sons, Ltd. [source] Simultaneous determination of avermectins in bovine tissues by LC-MS/MSJOURNAL OF SEPARATION SCIENCE, JSS, Issue 21 2009Koichi Inoue Abstract Analytical method for the simultaneous quantification of avermectins (AVMs), abamectin B1a, abamectin 8,9-Z isomer B1a, emamectine benzoate B1a, emamectine benzoate 8,9-Z isomer B1a, ivermectin, eprinomectin B1a, doramectin and moxidectin in bovine tissues (muscle, liver and fat) was developed by LC-MS/MS in electrospray positive ion mode. The separation was achieved on a short TSK-GEL ODS 100V column with the mobile phase consisting of acetonitrile and aquatic 0.1,mM ammonium formate containing 0.1% formic acid v/v at a flow rate of 0.2,mL/min with gradient elution. Liquid,liquid extraction with isooctane was used for the sample extraction/preparation of analytes in bovine samples. The linearity of the calibration curves was excellent in matrix-matched standards, and yielded the coefficients (r2=0.997,0.999, range from LOQ to 500, 1000 or 5000,ng/g) of determination of the target analytes. Recoveries were in the range of 87.9,99.8% with associated precision values (within-day: 1.5,7.4%, n=6, and between-day: 1.5,8.4% for 3 days) for repeatability and reproducibility. LC-MS/MS method has been proven to be highly efficient and suitable for the simultaneous determinations of eight AVMs in bovine tissue samples. [source] Pressurised liquid extraction of polycyclic aromatic hydrocarbons from gas and particulate phases of atmospheric samplesJOURNAL OF SEPARATION SCIENCE, JSS, Issue 7 2009Maria Rosa Ras Abstract Pressurised liquid extraction (PLE) was applied to determine the atmospheric levels of 16 polycyclic aromatic hydrocarbons (PAHs) in the gas and particulate phases. The method involved high-volume air sampling with quartz fibre filters (QFFs) and polyurethane foam (PUF) plugs and analytes were subsequently extracted from the samples by PLE, and determined with GC-MS. We optimised the PLE conditions for the solvent, the number of cycles and extraction temperature. Recoveries were higher than 90% for most compounds. Method LODs and LOQs were between 0.001 and 0.02 ng/m3 and between 0.01 and 0.05 ng/m3. Air samples were taken from a site in the region of Tarragona in Catalonia, Spain, where one of the largest petrochemical complexes in southern Europe is located. The total concentration of PAHs were from 6.7 to 27.66 ng/m3, with predominant levels of PAHs appearing in the gas phase (48,81%), and an average level of benzo[a]pyrene, the most carcinogenic PAH, of 0.86 ng/m3. [source] Solid-phase microextraction for the determination of benzoylureas in orange juice using liquid chromatography combined with post-column photochemically induced fluorimetry derivatization and fluorescence detectionJOURNAL OF SEPARATION SCIENCE, JSS, Issue 1 2008Piedad Parrilla Vázquez Abstract A solid-phase microextraction (SPME) method has been developed for the determination of six benzoylureas (diflubenzuron, triflumuron, hexaflumuron, teflubenzuron, lufenuron, and flufenoxuron) in natural orange juice based on the direct immersion mode of a 60 ,m polydimethylsiloxane/divinylbenzene fiber. An orange juice was obtained from blended, homogenized, and diluted ecological natural orange juice samples. An aliquot of 3 mL of a spiked sample was extracted under optimum SPME conditions. The determination of benzoylureas was carried out using HPLC combined with post-column photochemically induced fluorimetry derivatization and fluorescence detection. The limits of quantification obtained in matrix were within the range of 0.02 to 0.04 mg/kg and these limits are lower than the maximum residue levels established in Spanish regulations for all pesticides in this study. Recoveries in juice samples ranged between 85 and 110% and relative standard deviations between 1.8 and 7.4%. [source] Multiresidue HPLC analysis of ten quinolones in milk after solid phase extraction: Validation according to the European Union Decision 2002/657/ECJOURNAL OF SEPARATION SCIENCE, JSS, Issue 15 2007Eleni A. Christodoulou Abstract A rapid and sensitive analytical method was developed for the residue analysis of ten quinolones (enoxacin (ENO), ofloxacin (OFL), norfloxacin (NOR), ciprofloxacin (CIP), danofloxacin (DAN), enrofloxacin (ENR), sarafloxacin (SAR), oxolinic acid (OXO), nalidixic acid (NAL), and flumequine (FLU)) in cow's milk. The analytes were extracted from milk by a deproteinization step followed by a simple SPE cleanup procedure using LiChrolut RP-18 Merck cartridges. Recoveries varied between 75 and 92%. HPLC separation was performed at 25°C using an ODS-3 PerfectSil® Target (250×4 mm2) 5 ,m analytical column (MZ-Analysentechnik, Germany). The mobile phase consisted of a mixture of TFA 0.1%,CH3CN,CH3OH, delivered by a gradient program at the flow rate of 1.2 mL/min. Elution of the ten analytes and the internal standard (caffeine, 7.5 ng/,L) was completed within 27 min. Column effluent was monitored using a photodiode array detector, set at 275 and 255 nm. The developed method was validated according to the criteria of Commission Decision 2002/657/EC. The LODs of the specific method of quinolones' determination in milk varied between 1.5 and 6.8 ng/,L. [source] Rapid quantification of sucrose esters in oriental tobacco by liquid chromatography-ion trap mass spectrometryJOURNAL OF SEPARATION SCIENCE, JSS, Issue 1 2007Li Ding Abstract A rapid and sensitive LC-MS/MS method was developed for the quantitative determination of sucrose esters (SEs) in Oriental tobacco samples. The sample preparation involved a 10-min sonication extraction procedure with acetone and five-fold dilution of the extract with methanol. The experiment was carried out in positive ion mode by ESI IT mass spectrometer. Because of lack of authentic standards of SEs, sucrose octa-acetate (internal standard, IS) was used as a surrogate to validate the proposed method. Matrix-matched standard calibration was used for quantification of IS in the spiked samples. Under optimized MS/MS conditions, an LOQ of 3.9 ,g/g was achieved for IS, with an LOD of about 1.2 ,g/g. Recoveries for IS were 95,97%. Among 19 monitored SEs, the contents of 11 SEs had RSDs lower than 13.7%. The method, with very little sample handling and good sensitivity, was applied to the rapid quantification of SEs in four Oriental tobacco samples. It appears that the sum of contents of the five SEs with MW 650, 664, and 678 Da occupied approximately 80% of the total content of SEs. [source] Analysis of gastrodin and tetramethylpyrazine in traditional Chinese preparations by micellar electrokinetic chromatographyJOURNAL OF SEPARATION SCIENCE, JSS, Issue 6-7 2003Wang Rongying Abstract A simple, rapid, and accurate micellar electrokinetic chromatographic method has been developed for determination of gastrodin and tetramethylpyrazine in three traditional Chinese preparations: Zhennaoning jiaonang, Yangxue shengfa jiaonang, and Xiaoshuan zaizao wan. Running buffer comprising 50 mM sodium tetraborate and 15 M sodium dodecylsulfate (SDS), pH 9.50, was found to be most suitable for the separation. All experiments was performed with a 47 cm (40 cm effective length)×75 ,m ID uncoated fused-silica capillary and UV detection at 200 nm. The linear calibration ranges were 2.5,200 ,g mL,1 (R = 0.999) for gastrodin and 5.0,200 ,g mL,1 (R = 0.997) for tetramethylpyrazine; the detection limits were 0.5 ,g mL,1 and 0.8 ,g mL,1, respectively. Recoveries of the two analytes from the samples, calculated by use of a method described in detail in the text, were between 94.21 and 104.46%. The amounts of gastrodin and tetramethylpyrazine in the preparations were easily determined within 10 min. [source] Evaluation of an internal positive control for Cryptosporidium and Giardia testing in water samplesLETTERS IN APPLIED MICROBIOLOGY, Issue 3 2003M. Warnecke Abstract Aims: An internal positive control for Cryptosporidium and Giardia monitoring was evaluated for use in routine water monitoring quality control. The control, known as ColorSeed C&G (BTF Pty Ltd, Sydney, Australia), is a suspension containing exactly 100 Cryptosporidium oocysts and 100 Giardia cysts that have been modified by attachment of Texas Red to the cell wall, allowing them to be differentiated from unmodified oocysts and cysts. The control enables recovery efficiencies to be determined for every water sample analysed. Methods and Results: A total of 494 water samples were seeded with ColorSeed C&G and with unlabelled Cryptosporidium and Giardia and then analysed. Additionally, the robustness of the ColorSeed labelling was challenged with various chemical treatments. Recoveries were significantly lower for the ColorSeed Texas Red labelled Cryptosporidium and Giardia than recoveries of unlabelled Cryptosporidium and Giardia. However, the differences in recoveries were small. On average ColorSeed Cryptosporidium recoveries were 3·3% lower than unlabelled Cryptosporidium, and ColorSeed Giardia recoveries were 4% lower than unlabelled Giardia. Conclusions: ColorSeed C&G is suitable for use as an internal positive control for routine monitoring of both treated and raw water samples. Significance and Impact of the Study: The small differences in recoveries are unlikely to limit the usefulness of ColorSeed C&G as an internal positive control. The ColorSeed labelling was found to be robust after different treatments. [source] | ||||||||||||||||||||||||||||||||||||||||||||||