Raman spectroscopic signature of semen and its potential application to forensic body fluid identification, this paper was recently published in FSI and is an update on the ones from last year (
Raman spectroscopy offers great potential for the nondestructive confirmatory identification of body fluids and
Analysis of body fluids for forensic purposes: From laboratory testing to non-destructive rapid confirmatory identification at a crime scene). This study, more indepth than the previous ones and focussing on semen, identified three key indicating components of interest from a raman spectrum that can be used to identify a semen sample. However, there were several contributing species (shown in the spectrum below) that made up the three components namely:
Tyrosine (peaks in green)
Albumin (peaks in blue)
Choline (peak in yellow)
Spermine phosphate hexahydrate (peaks in purple)
The potential for being able to identify dried semen on tapings using a confocal approach, would appear to be possible, particularly useful for old (cold) cases where the items of clothing may no longer be available.
One slight concern was the strength of the laser used to obtain the data in the paper. 115mW seems like a lot for a biological sample which you would not wish to heat. No attempt was made to assess the impact of the technique on any DNA process after analysis so its not a validation of the process for forensic use, but its a step in the right direction.
