Sample preparation analyte/matrix

Several methods are available for the analysis of trichloroethylene in biological media. The method of choice depends on the nature of the sample matrix cost of analysis required precision, accuracy, and detection limit and turnaround time of the method. The main analytical method used to analyze for the presence of trichloroethylene and its metabolites, trichloroethanol and TCA, in biological samples is separation by gas chromatography (GC) combined with detection by mass spectrometry (MS) or electron capture detection (ECD). Trichloroethylene and/or its metabolites have been detected in exhaled air, blood, urine, breast milk, and tissues. Details on sample preparation, analytical method, and sensitivity and accuracy of selected methods are provided in Table 6-1. 

Sample matrix Sample preparation Analytical method Detection limit Accuracy Reference... 

Sample Matrix Sample Preparation Analytical Limit (% Recovery) Reference... 

Samples/ matrix Equipment/sample preparation Analyte Detection limits References... 

Finally, there is the need for proper documentation, which can be in written or electronic forms. These should cover every step of the measurement process. The sample information (source, batch number, date), sample preparation/analytical methodology (measurements at every step of the process, volumes involved, readings of temperature, etc.), calibration curves, instrument outputs, and data analysis (quantitative calculations, statistical analysis) should all be recorded. Additional QC procedures, such as blanks, matrix recovery, and control charts, also need to be a part of the record keeping. Good documentation is vital to prove the validity of data. Analyt-... 

Sample Matrix Biomarker Sample Preparation Analytical Method LOD References... 

Species-specific isotope-dilution techniques can eliminate most of the discussed sources of errors in quantification, provided the isotopically labeled species has the same identity as the analyte, is available in high purity and stability, and the equilibration between the natural species (analyte) and the isotopically labeled species is achieved at the earliest possible stage of sample preparation. Quantification via the isotope ratios can then compensate for analyte losses during sample preparation, for matrix dependent changes in sensitivity, low column recovery, and species transformation, provided there is still a clearly detectable peak of the analyte for accurate measurement of the isotope ratio(s). However,... 

There may be several other reasons for using sample preparation. Analytes are often changed chemically (i.e., are derivatized) to become better suited for analysis or detection. Eurthermore, sample preparation should be robust to provide reproducible samples independent of variations in the sample matrix. 

Authors Target UV ftlters" Type of matrix Sample preparation Analytical technique Remarks ... 

The following experiments introduce students to the importance of sample preparation and methods for extracting analytes from their matrix. Each experiment includes a brief description of the sample and analyte, as well as the method of analysis used to measure the analyte s concentration. 

Before sample preparation, surrogate compounds must be added to the matrix. These are used to evaluate the efficiency of recovery of sample for any analytical method. Surrogate standards are often brominated, fluorinated, or isotopically labeled compounds that are not expected to be present in environmental media. If the surrogates are detected by GC/MS within the specified range, it is... 

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