Forensic electrochemical presumptive blood test based on the voltammetric behaviour of methylene blue and whole blood

Abstract

The ability to identify the presence of blood residues is important in a number of fields, such as in the forensic and archaeological sciences. A number of tests presently exist; however, these suffer drawbacks, such as difficulties with the interpretation of positive results and interferences from common chemicals and reagents. In this present study, for the first time, we demonstrate the possibility of applying an electrochemical technique as a semi-quantitative presumptive test for the detection of blood residues. Our method is based on the cyclic voltammetric behaviour of the methylene blue mediated detection of haemoglobin present in blood residues. Initial studies investigated the voltammetric behaviour of methylene blue and the possibility of using it for the mediated detection of haemoglobin. Using this approach, it was shown to be possible to detect haemoglobin and hence the presence of blood. We have shown the possibility of successfully identifying the presence of whole blood residues recovered from cloth gaining a coefficient of variation of 5.3%. Our method was shown to overcome many of the commonly reported interferences and interpretation issues. The results demonstrate that the developed method could be successfully used for the detection of blood residues in such samples requiring only simple dilution of the sample.