Migration Analytical determination

The EU limit of the overall migration is 10 mg/dm or 60 mg/kg. Because olive oil is a severe solvent compared with most fatty foods, a reduction factor ranging from 2-5 may be applied depending on the food. Chocolate has, for example, a reduction factor of 5, which means that the value obtained for the overall migration into simulant D must be divided by 5 before checking it against the limit (Directive 85/572/EEC). Eurthermore, it should be kept in mind that analytical error in the determination of the overall migration was determined by the EU as 2 mg/dm or 12 mg/kg for the aqueous food simulants (A, B and C), whilst the error is 3 mg/dm or 20 mg/kg for the fatty food simulant (D). 

Restrictions for the residual amount of a component instead of a specific migration limit are set by the legislator in cases where specific migration of a component is difficult to obtain (for example, because the component is very volatile) or impossible to determine directly (for example, if the component is very reactive and would react with the food simulant). There are two ways to determine the residual content, by worst-case calculation or by analytical determination. The generic approach is shown in Eig. 5.3. 

As concluded by Menzinger et CE will only fully augment chromatographic techniques in the routine determination of pesticide residues when software becomes capable of compensating for the intrinsic variability in analyte migration times. This... 

Applications Radiotracer measurements, which combine high sensitivity and specificity with poor spatial resolution, have been used for migration testing. For example, studies have been made on HDPE, PP and HIPS to determine effects of manufacturing conditions on migration of AOs from plastic products into a test fat [443]. Labelled antioxidant was determined radio-analytically after 10 days at 40 °C. Acosta and Sas-tre [444] have used radioactive tracer methods for the determination of styrene ethyl acrylate in a styrene ethyl acrylate copolymer. 

Two hundred and fifty three till (C-horizon) samples were collected and analyzed to detemine suitable analytical methods to delineate till geochemical signatures that reflect Zn-Pb-Ag mineralization and to determine possible pathways of element migration from the bedrock to till. Results of a study conducted at the Mount Fronsac North deposit are discussed here. 

The precision of the assay for nonreduced samples was demonstrated by the evaluation of six independent sample preparations on a single day (repeatability) and the analysis of independent sample preparations on three separate days by two different analysts (intermediate precision). The RSD values for the migration time were 0.9%. The RSD values for peak area percent of the main peak and the minor peaks in the profile were 0.6 and 12.6%, respectively. The higher variability observed with the minor peaks was determined to be primarily related to the sample heating during preparation for the analysis. These results demonstrate that the use of uncoated fused-silica capillaries in combination with a sieving matrix can provide adequate precision and analyte recovery. 

For high reproducibility of migration times and peak areas the sample matrix should be identical for all samples analyzed together. While this is challenging for forensic applications where analytes in whole blood or urine are determined, this requirement can be fulfilled easily in pharmaceutical analysis. After sample preparation of the drug product, the sample matrix is similar in most cases. The composition of blood or urine depends on its source. Thus, the changing sample matrix has more impact on the quality of the CE analysis. 

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