Residue levels, analytical methodology

Gros M, Petrovic M, Barcelo D (2006) Development of a multi-residue analytical methodology based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for screening and trace level determination of pharmaceuticals in surface and wastewaters. Talanta 70 678-690... 

Analytical methodology—This section should refer to the specific analytical method(s) to be used for the specific products, cleaning agents, and equipment for the protocol being evaluated. Many companies choose to have the detailed analytical methodology described in a separate report and reference only the report number in the actual protocol. There are certain parameters that should be included in the actual protocol, however. For example, the sensitivity of the analytical method, expressed either as the LOD or LOQ, should be included in the protocol since it will be necessary that the sensitivity of the analytical method be below the acceptance criteria for the residues so that a result of none detected can be interpreted, ft must be remembered that none detected does not mean that there was no residue present, but only that the level of residue was below the limit of detection of the analytical method. 

In order to establish a tolerance, the Agency must be able to predict the level of residue that will occur. The data used for this purpose includes data on metabolism, analytical methodology, and the results of field trials conducted to determine the actual level of residue anticipated (1). 

Analytical methodology used to determine the level of residue likely to occur must be suitable for enforcing the tolerances. That is, the methodology must (1) be capable of determining all components of the residue as specified in the tolerance 2) be of adequate specificity and sensitivity ... 

A large number of analytical methodologies aiming the detection of pesticide residues in VOO at very low concentration levels are being published nowadays. Among them, GC remains the most extensively used technique in routine laboratories for the analysis of these analytes in VOO it is usually employed in combination with ECD, NPD, and EPD. However, the relatively low sensitivity needed for some pesticides and the difficulties in confirmation of results due to the complexity of the matrix under study force to use GC-MS. With the use of GC-MS/MS techniques, simultaneous determination and confirmation of pesticide residues has been obtained in one analytical run this improves the analytical accuracy and shortens the analytical time [112,113],... 

In this chapter, the main analytical techniques and the methods currently employed in industrial and research laboratories for the analysis of important classes of additives are reviewed. The use of both gas chromatographic and liquid chromatographic methods coupled with mass spectrometry features prominently. Such methodology enables the sensitive and specific detection of many types of organic additives in polymeric materials to parts per billion (jig/kg) levels. Much of the development of these methods has been undertaken as part of research into the migration or extraction of species from food-contact and medical materials [5-7], This chapter also includes some discussion on the analysis of residual monomers and solvents. 

The results have shown that we have developed a sensitive and specific ELISA assay for the analysis of clomazone residues from soil samples. The procedures have demonstrated good recovery of clomazone from soil, and excellent correlation of the ELISA test results with standard GLC methodology. In addition, the results of the ELISA tests demonstrate good correlation between the observed soil levels of clomazone, and crop injury when the bioassay is performed under controlled, greenhouse conditions. This assay could, therefore, be used as a more rapid and convenient analytical method over the standard GLC technique after further validation. 

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