Search results for "Routine analysis"
showing 6 items of 6 documents
PCR-based procedures for detection and quantification of Staphylococcus aureus and their application in food.
2006
Aims: To evaluate the specificity of nuc targeted primers for PCR detection of Staphylococcus aureus in different food matrices and to establish a RTQ-PCR procedure suitable for the routine detection and quantification of this pathogen in food. Methods and Results: Specificity of nuc targeted primers (Pri1–Pri2 and the newly designed RTQ-PCR primers) was tested on a total of 157 strains of genetically confirmed identity, including reference and food isolates. PCR detection on artificially inoculated beef samples by DNA extraction using a DNeasy Tissue Kit (Qiagen GmhH, Hilden, Germany) showed a sensitivity value around 103 CFU g−1. The two RTQ-PCR systems, incorporating SYBR-Green I and T…
One-year monitoring of aflatoxins and ochratoxin A in tiger-nuts and their beverages.
2011
A sensitive and selective liquid chromatography-triple quadrupole-tandem mass spectrometry (LC-ESI-MS-MS) method was developed for the routine analysis of aflatoxins (AFB(1), AFB(2), AFG(1) and AFG(2)) and ochratoxin A (OTA) in tiger nuts and tiger-nut beverage (horchata). A matrix solid phase dispersion was adapted to eliminate lipidic interferences. The solid support was C(18), while the elution solvent was acetonitrile. Mean recoveries obtained at two fortification levels were 72-83% and 71-81% for horchata and tiger nut respectively with relative standard deviations (RSDs) <13% and 15% respectively. The LC-MS-MS method allowed quantification and identification at low levels in two matri…
Rapid and direct gas chromatographic determination of oxalic acid in urine
1979
The known methods of oxalic acid determination are not suitable for reliable, rapid and economical routine analysis. A rapid gas chromatographic method has been developed which dispenses with separation operations and measures oxalic acid as a diethylester by means of back-flushing, and using malonic acid as an internal standard. One determination can be conducted within 6 to 8 min. and preparation of the specimen takes about the same amount of time. If the gas chromatographic conditions are changed and more time is permitted for analysis, numerous other extractable acidic metabolites can also be determined.
Procedures for Antibiotic Residues in Bovine Muscle Tissues
2011
Abstract Acetonitrile extraction followed by primary-secondary amine dispersive SPE cleanup QuEChERS (quick, easy, cheap, effective, rugged, and safe), was compared to pressurized liquid extraction (PLE) using water at 70°C for 10 min at 1500 psi for the determination of 16 veterinary drugs in bovine muscle tissues by LC/MS/MS. PLE was significantly more effective for the extraction of veterinary drugs (ranging from 69 to 103% with RSD ≤ 18%) than QuEChERS (ranging from 19 to 89% with RSD ≤ 19%). Linearity of the calibration curves was obtained over the range considered (from 10 μg/kg or LOQ to 1000, μg/kg) with r2 ≥ 0.99 for all the analytes by both methods. Although an internal standard w…
Use of polarography as a quality-control method for determining diacetyl in citrus and vegetable juices, yoghurt and butter
2002
The determination of diacetyl permits the detection of microbial growth in the processing of citrus fruit before the appearance of other organoleptic, chemical or microbiological changes. It also makes it possible to detect a break in the cold chain during distribution and sale. The study proposed a polarographic method for the determination of diacetyl that allowed routine analysis with the aim of detecting possible contamination in the citrus juice manufacturing chain (orange and orange-carrot). The analytical performance of the method in terms of a linearity from 0 to 960 microg ml(-1), a recovery of 97 to 98%, a precision of 3.2 to 4.8%, and a sensitivity of 0.2 ng ml(-1) for juices ind…
Surveillance of pesticide residues in fruits from Valencia during twenty months (2004/05)
2010
Abstract The aim of this study was to investigate the pesticide residues in market fruits (oranges, tangerines, nectarines, peaches and khakis) from one Valencian Cooperative (Spain) and to conduct a monitoring of 32 organophosphorous, organonitrogen and organohalogenated pesticides and nine dithiocarbamate fungicides (DTCFs) usually applied on cultures of this area. Extracts were obtained by an official procedure for routine analysis based on ethyl acetate extraction. Residues of pesticides were determined by gas chromatography with nitrogen phosphorous detector (NPD), electron-capture detector (ECD) and mass spectrometry (MS) detectors. Mean recoveries obtained at fortification levels bet…