166
D. K. Pandey et al.
the person from the sample was taken, sample dilution, and sample age [165]. In
this analysis, they found that after drying the blood, the scattering peaks at 1155
and 1511 cm
−1 vanishes, and this band was not present in a sample that was stored
for more than a week. Certainly, this research demonstrates the ability of Raman
spectroscopy for blood analysis, both in the laboratory and at the crime scene. Zou
et al. showed the ability of Raman spectroscopy to classify an unknown material
that may be human blood or semen without the use of chemical reagents [166]. In
this study, they found that Raman scattering peaks at 2907 and 2968 cm
−1 is due to
the presence of semen, while peaks at 1057 cm
−1 are only found in human semen
and peaks at 1082 and 1165 cm
−1 are unique to blood spectra. In combination with
the multivariate data analysis, Lednev and the group used Raman spectroscopy to
construct a statistical method that accurately identified the race of all 18 semen donors
[167]. Results from this research indicate that Raman spectroscopy may be a valuable
resource for forensic investigators. Al-Hetlani et al. recorded Raman spectra of the
dry traces of oral fluid with advanced statistical tools to distinguish between smoker
and non-smoker donors (differing gender, age, and race) [168]. Casey et al. recently
showed the results of Raman spectroscopy, combined with chemometric analysis,
which specifically discriminates between body fluids and a range of environmental
interfaces (EIs) [169]. Shaine et al. reported 785 nm of excited SERS spectra of dried
bloodstains and the analysis of these spectra indicates that this blood signature can be
classified with 100% specificity and sensitivity concerning other body fluid’s SERS
spectra [170]. All these latest studies indicate that Raman spectroscopy can be very
useful in the scene of crime investigations where identification of body fluids along
with the various EIs is most relevant.
4.3.2 Document Examination
Forensic inspection of the questioned documents may include the examination of
many factors including signatures, the handwriting of individuals, dating and changes
made in a document, determining the sources, and counterfeit documents [171].
Buzzini and Suzuki presented a comprehensive overview of forensic applications of
Raman spectroscopy and looked specifically at the study of ink and paint evidence of
pigments and dyes [172]. Using Raman spectroscopy, Lee et al. identified ballpoint
pen inks (black and blue) based on a visual analysis of their spectra and identified
major marker bands [173]. Such bands have been matched for the spectra of various
types of pen inks. This technique enabled blue ink to be segregated with 94% accuracy
and 95% for the black ink. Further, Mohamad Asri et al. reported that the integration
of chemometrics with Raman spectroscopy could enhance the descriptions of the
various pen inks. [174, 175]. The methodology of principal component analysis
(PCA) enables the grouping of blue and red ballpoint pen inks by type [175]. In
another piece of work, Raman and Fourier transform infrared (FTIR) spectroscopy,
together with PCA and Pearson’s product-moment correlation coefficients (PPMC),
enabled the classification of unidentified ink [174]. Borba et al. employed another
chemometric approach where multivariate curve resolution alternating least squares
D. K. Pandey et al.
the person from the sample was taken, sample dilution, and sample age [165]. In
this analysis, they found that after drying the blood, the scattering peaks at 1155
and 1511 cm
−1 vanishes, and this band was not present in a sample that was stored
for more than a week. Certainly, this research demonstrates the ability of Raman
spectroscopy for blood analysis, both in the laboratory and at the crime scene. Zou
et al. showed the ability of Raman spectroscopy to classify an unknown material
that may be human blood or semen without the use of chemical reagents [166]. In
this study, they found that Raman scattering peaks at 2907 and 2968 cm
−1 is due to
the presence of semen, while peaks at 1057 cm
−1 are only found in human semen
and peaks at 1082 and 1165 cm
−1 are unique to blood spectra. In combination with
the multivariate data analysis, Lednev and the group used Raman spectroscopy to
construct a statistical method that accurately identified the race of all 18 semen donors
[167]. Results from this research indicate that Raman spectroscopy may be a valuable
resource for forensic investigators. Al-Hetlani et al. recorded Raman spectra of the
dry traces of oral fluid with advanced statistical tools to distinguish between smoker
and non-smoker donors (differing gender, age, and race) [168]. Casey et al. recently
showed the results of Raman spectroscopy, combined with chemometric analysis,
which specifically discriminates between body fluids and a range of environmental
interfaces (EIs) [169]. Shaine et al. reported 785 nm of excited SERS spectra of dried
bloodstains and the analysis of these spectra indicates that this blood signature can be
classified with 100% specificity and sensitivity concerning other body fluid’s SERS
spectra [170]. All these latest studies indicate that Raman spectroscopy can be very
useful in the scene of crime investigations where identification of body fluids along
with the various EIs is most relevant.
4.3.2 Document Examination
Forensic inspection of the questioned documents may include the examination of
many factors including signatures, the handwriting of individuals, dating and changes
made in a document, determining the sources, and counterfeit documents [171].
Buzzini and Suzuki presented a comprehensive overview of forensic applications of
Raman spectroscopy and looked specifically at the study of ink and paint evidence of
pigments and dyes [172]. Using Raman spectroscopy, Lee et al. identified ballpoint
pen inks (black and blue) based on a visual analysis of their spectra and identified
major marker bands [173]. Such bands have been matched for the spectra of various
types of pen inks. This technique enabled blue ink to be segregated with 94% accuracy
and 95% for the black ink. Further, Mohamad Asri et al. reported that the integration
of chemometrics with Raman spectroscopy could enhance the descriptions of the
various pen inks. [174, 175]. The methodology of principal component analysis
(PCA) enables the grouping of blue and red ballpoint pen inks by type [175]. In
another piece of work, Raman and Fourier transform infrared (FTIR) spectroscopy,
together with PCA and Pearson’s product-moment correlation coefficients (PPMC),
enabled the classification of unidentified ink [174]. Borba et al. employed another
chemometric approach where multivariate curve resolution alternating least squares