Animal matrices

The accuracy and precision of the analytical methods were determined by the average and standard deviation of individual method recoveries of the fortitied-control samples in 50 different matrices (see Tables 1 and 2). These methods were also demonstrated to be very rugged based on the results of accuracy and precision for a variety of crop and animal matrices. 

For animal matrices, homogenize 10 g of a prepared sample with acetonitrile (50mL) for 5min and centrifuge the mixture at 3000rpm for 3 min. Decant the supernatant extract into a measuring cylinder (100-mL) and adjust the volume of the extract to a known value. 

During the period June, 1994, to June, 1996, a monitoring program for analyzing nicarbazin residues in several animal matrices was also carried out... 

Matrix Effect and Recovery For LC-MS/ MS-based methods, the signal suppression or enhancement of the analyte due to the presence of the matrix interferences (matrix effects) in MS/MS detection should be evaluated by comparing the response (peak area) of the analyte and the IS from the extracted blank samples post-fortified with the analyte and the IS with the response of neat solutions with both the analyte and the IS at the same concentrations as above. Matrix effects should be evaluated in one pooled batch of animal matrix or in at least three different batches of human matrix, using three replicates at a minimum of three QC concentrations (e.g., low quality control [LQC], medium quality control [MQC], high quality control [HQC]) with IS at working concentration. The coefficient of variation (CV%) of the matrix effect variability should be <15% at each concentration level and between the three (LQC, MQC, and HQC) concentration levels. 

The recovery of an analyte and the associated IS in an LC-MS/MS assay is the percentage (%) of the LC-MS/ MS response (peak area) obtained from the extracted QC samples (LQC, MQC, and HQC) prepared from one pooled batch of animal matrix or from at least three different batches of human matrix in at least three replicates for each concentration level compared with those... 

Numerous high pressure Hquid chromatographic techniques have been reported for specific sample forms vegetable oHs (55,56), animal feeds (57,58), seta (59,60), plasma (61,62), foods (63,64), and tissues (63). Some of the methods requite a saponification step to remove fats, to release tocopherols from ceHs, and/or to free tocopherols from their esters. AH requite an extraction step to remove the tocopherols from the sample matrix. The methods include both normal and reverse-phase hplc with either uv absorbance or fluorescence detection. AppHcation of supercritical fluid (qv) chromatography has been reported for analysis of tocopherols in marine oHs (65). 

Extracellular matrix The surfaces of animal cells are covered with a flexible and sticky layer of complex carbohydrates, proteins, and lipids. This complex coating is cell-specific, serves in cell-cell recognition and communication, creates cell adhesion, and provides a protective outer layer. 

Succinyl-CoA derived from propionyl-CoA can enter the TCA cycle. Oxidation of succinate to oxaloacetate provides a substrate for glucose synthesis. Thus, although the acetate units produced in /3-oxidation cannot be utilized in glu-coneogenesis by animals, the occasional propionate produced from oxidation of odd-carbon fatty acids can be used for sugar synthesis. Alternatively, succinate introduced to the TCA cycle from odd-carbon fatty acid oxidation may be oxidized to COg. However, all of the 4-carbon intermediates in the TCA cycle are regenerated in the cycle and thus should be viewed as catalytic species. Net consumption of succinyl-CoA thus does not occur directly in the TCA cycle. Rather, the succinyl-CoA generated from /3-oxidation of odd-carbon fatty acids must be converted to pyruvate and then to acetyl-CoA (which is completely oxidized in the TCA cycle). To follow this latter route, succinyl-CoA entering the TCA cycle must be first converted to malate in the usual way, and then transported from the mitochondrial matrix to the cytosol, where it is oxida-... 

In biology, extracellular matrix (ECM) is the extracellular part of animal tissue that usually provides structural support to the cells in addition to performing various other important functions. ECM is the defining feature of connective tissue in animals. ECM includes the interstitial matrix and the basement membrane. 

A safety match head is, essentially, K chlorate in a matrix of animal glue. The striking strip is composed of red P in a similar binder. Use of additives and adjustments in the mfg process results in a safety match which ignites easily when rubbed on the striking surface. The friction and contact of K chlorate crystals with red P results in the ignition of the match head which, in turn, causes the ignition of paraffin impregnated in the match splint... 

Analysis of methyl parathion in sediments, soils, foods, and plant and animal tissues poses problems with extraction from the sample matrix, cleanup of samples, and selective detection. Sediments and soils have been analyzed primarily by GC/ECD or GC/FPD. Food, plant, and animal tissues have been analyzed primarily by GC/thermionic detector or GC/FPD, the recommended methods of the Association of Official Analytical Chemists (AOAC). Various extraction and cleanup methods (AOAC 1984 Belisle and Swineford 1988 Capriel et al. 1986 Kadoum 1968) and separation and detection techniques (Alak and Vo-Dinh 1987 Betowski and Jones 1988 Clark et al. 1985 Gillespie and Walters 1986 Koen and Huber 1970 Stan 1989 Stan and Mrowetz 1983 Udaya and Nanda 1981) have been used in an attempt to simplify sample preparation and improve sensitivity, reliability, and selectivity. A detection limit in the low-ppb range and recoveries of 100% were achieved in soil and plant and animal tissue by Kadoum (1968). GC/ECD analysis following extraction, cleanup, and partitioning with a hexane-acetonitrile system was used. 

The earlier work of Miller (35), Outright (37), and Brady (5) on nonmedicated implants provided an excellent basis for further studies on specific controlled release formulations such as the determination of the biodegradation rates of lactide/glycolide drug-loaded microspheres (38). Those studies were done with l c-iabeled polymers produced from DL-lactic acid and glycolide. The final formulations tested in rats were microspheres loaded with H-labeled steroid and polymer as the matrix. The microspheres were administered intramuscularly and animals were serially sacrificed over a period of about a year. 

S-type lectins P-Galactoside-binding animal lectins with roles In cell-cell and cell-matrix interactions... 

Even though PAHs are commonly determined by GC or HPLC, there are no matrix reference materials for PAHs in urine or serum. A number of reference materials certified for PAHs in animal tissue are available, but they are intended for environmental applications, see Section 3.4. 

The literature includes a number of mis-matches, the following standing as examples for the many The use of bovine liver and other animal tissues for QC in the analysis of hmnan body fluids should not be considered by analysts. The matrix and the levels of trace elements do not match the levels to be analyzed, which may lead to serious errors. An even more severe mis-use was recently reported by Schuhma-cher et al. (1996) for NIST SRM 1577a Bovine Liver, which was used for QC in the analysis of trace elements in plant materials and soil samples in the vicinity of a municipal waste incinerator. Also recently, Cheung and Wong (1997) described how the quality control for the analysis of trace elements in clams (shellfish) and sediments was performed with the same material NIST SRM 1646, Estuarine sediment. Whilst the selected SRM was appropriate for sediments, its usefulness as a QC tool for clams is difficult to prove see also Chapter 8. This inappropriate use is the more mystifying because a broad selection of suitable shellfish RMs from various producers is available. 

Health, Environmental, Quarantine and Other Regulations Many countries have strict regulations designed to protect the ecosystem and agrochemical business. For example any matrix material derived from pork, beef, sheep or horse tissue has to be accompanied with a Veterinary Certificate confirming that the matrix material is free of certain specified diseases before it can be imported into the EU. The Australian import restrictions are even tougher and require the importer to obtain prior permission to import plant and animal materials and products derived from biological materials. To get an import license it is necessary to complete an application, which includes information from the producer about the actual production process used to prepare the matrix ... 

Owing to the complexity of multi-residue methods for products of animal origin, it is not possible to outline a simple scheme however, readers should refer to methods described in two references for detailed guidance (Analytical Methods for Pesticides in Foodstuffs, Dutch method collection and European Norm EN 1528. ) There is no multi-method specifically designed for body fluids and tissues. The latter matrix can be partly covered by methods for products of animal origin. However, an approach published by Frenzel et al may be helpful (method principle whole blood is hemolyzed and then deproteinized. After extraction of the supernatant, the a.i. is determined by GC/MS. The LOQ is in the range 30-200 ag depending on the a.i.). 

These two terms (IDL and IQL) define only the limitations of the instmment. When analyzing real-life samples such as plant or animal tissue or even soil and ground water samples, matrix interference must be taken into consideration in order to define detection limits. This is because these real-life matrices are made up of hundreds (or even thousands) of compounds. These compounds may interfere in several ways in the detection and quantification of the analyte of interest. 

To demonstrate the validity of an analytical method, data regarding working range/ calibration, recovery, repeatability, specificity and LOQ have to be provided for each relevant sample matrix. Most often these data have to be collected from several studies, e.g., from several validation reports of the developer of the method, the independent laboratory validation or the confirmatory method trials. If the intended use of a pesticide is not restricted to one matrix type and if residues are transferred via feedstuffs to animals and finally to foodstuffs of animal origin, up to 30 sets of the quality parameters described above are necessary for each analyte of the residue definition. Table 2 can be used as a checklist to monitor the completeness of required data. 

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