GHEP-ISFG proficiency test 2011: Paper challenge on evaluation of mitochondrial DNA results.

The GHEP-ISFG Working Group performed a collaborative exercise to monitor the current practice of mitochondrial (mt)DNA reporting. The participating laboratories were invited to evaluate a hypothetical case example and assess the statistical significance of a match between the haplotypes of a case (hair) sample and a suspect. A total of 31 forensic laboratories participated of which all but one used the EMPOP database. Nevertheless, we observed a tenfold range of reported LR values (32-333.4), which was mainly due to the selection of different reference datasets in EMPOP but also due to different applied formulae. The results suggest the need for more standardization as well as additional research to harmonize the reporting of mtDNA evidence.

Electroanalytical determination and fractionation of copper in wine.

Eight different bottled wines (six red wines and two white ones) were studied for copper determination and fractionation. For this purpose, copper determination by square wave voltammetry (SWV) and potentiometry (PSA) stripping analysis using Hg electrodes (drop and film, respectively) were carried out. Two direct procedures for the determination of total copper in wine are proposed; in both cases, drastic treatment of samples is not necessary, the procedures are very fast (estimated time to carry out an analysis is <10 min) and require no deaeration. Fractionating treatment consists of various HCl additions followed by the addition of ethylenediamine. Precision (RSD < 3%) and accuracy (recovery > 98%) data justify that both methods proposed are valid for total copper determination in wine. The wines studied displayed similar behaviors regarding fractionation: the percentages of total copper fractionated in each step are statistically similar: differences are lower than 2 S.