Abstract
In many crime scenes, detectives find minute lipsticks, pieces of clothes blood strain, cigarette butts among others materials. The traditional techniques such as thin layer chromatography, visible-absorption spectroscopy may not incriminate the victim. These techniques may make some crimes to go unsolved because of inadequate evidence at the crime scene or due to inadequate technology. The recent scientific developments in analytical methods and changes in technology have enabled scientist to begin detecting evidence from cosmetic smear, which were useless in the past. A basic analysis of the inorganic and organic constituents of the cosmetic smears helps in classifying the product used by the victim. The depth analysis conducted on the said lipstick or cosmetic smear would enable law enforcers to adduce evidence of the crime.
Introduction
The recent development in crime detection enables the law enforcement officers to collect information as well as chemicals used the suspects. At crimes scene or in victim’s house, the detectives may find lipstick used by the crime victim (Blackledge, 2007:8-12). The modern analytical methods enable the detection team to analyze the constituents of the chemicals in the lipstick and the traces of smear extracted from the victims lips of eyelashes.
Since the existing forensic labs do not contain national database of lipstick manufacturers, the lipstick found with the suspect and the other one found at the crime scene enables the forensic officers to compare the chemical components of the lipsticks. If detected that the victim had a contact with the lipstick found at the crime scene it would serve as circumstantial evidence (Severcan and Haris, 2012:365-372). In forensic studies, comparison of chemicals found in the lipstick and body extract are critical in proving the innocence of the victim.
Methods
The methods applied in lipstick analysis may be destructive or non-destructive. Both methods detect the chemical constituents in lipstick samples.
FTIR-ART Use Lipstick Analysis
In this method, ART machine radiates infrared light to the chemical samples of the lipstick to reveal the composition of the chemical constituents in samples (Wheeler and Wilson, 2011:226-248). The machine enables the person conducting the experiment to control the depth of light penetration in order to reveal specific information. The sample lipstick tested was 4000-650cm-1 at 4cm-1 and we collected background air. Finally, we controlled the light penetration to reveal the chemical components.
Result: all peaks are similar to the lipstick in positive control, which means that they are the same lipstick. Black means no peak. This result means that lipstick did not have any contamination.
MSP used: Lipstick Analysis
MSP method uses microspectrophotometer to analyze the microscopic chemical samples. In this experiment, collected white background of pure substance, spectrum of sample focused on three different areas, and we took three different reading. Take the chromaticity values. The result of the experiment revealed various colors of the samples taken.
Table3: MSP colorimetric data the average of the X,Y,Z values.
Destructive methods
UV-Vis Spectrophotometry
This is a destructive method because the chemicals used in the experiment undergo chemical change. We used 2ml of chloroform; extracted strains of samples marked in different tubes, took a negative control, took 3ml of the extracted sample, and recorded the observation on the spectra. We compared the result with the lipsticks sample. The result detected was similar to the lipstick chemicals indicating positive control.
Thin Layer Chromatography
In this method, we used the following chemicals 15ml of isoamyl alcohol, 15ml of acetone, 7.5 ml of deionized water and 15 drops of 6M ammonium hydroxide. We mixed the chemicals with samples of the lipstick. We also set negative and positive for the experiment. We placed the drops of the mixed sample extract on the TLC plate. Finally, we placed TLC plate on the solvent breaker before subjecting the plate to the UV light (Mayo, Miller, and Hannah, 2004:470-482). We calculated the result using the Rf values.
GC-MS Lipstick Analysis
This experiment used 2ml of chloroform. We extracted stains of each fabric into different marked tubes. We carried ultra-sonification of the samples for a period of 5 minutes. After this, we transferred each sample into individual eppendorf tube. The experiment centrifuged the each of samples at highest speed for 5 minutes and transferred the clean solvent layer into GC vial then sealed it. Lastly, the experiment added blank of 1 ml chloroform.
Results and Discussions
The observation made on FTIR-ART experiment shows that forensic experts can compare the chemical composition of lipstick found at the crime scene and samples extracted from the crime victim. When the result of the experiment is black, the investigation would be negative because it does not reveal any contamination between the samples compared (Salvador and Chisvert, 2007:149-152).
This method is useful when detectives are able to trace victim’s lipstick at the crime scene. The result received in the MSP experiment revealed that detective is able to extract sample chemicals from the victim’s cloth as observed in the denim experiment. The positive control set for the experiment enables the scientist conducting the study to observe the changes in behavior of the chemical samples (Chisum, and Turvey, 2011:98-102). It is also observable from the result that lipstick positive control gave an impressive result as opposed to denim and towel samples.
The result of the thin layer chromatography indicated that chemical sample of the lipstick could be detected. However, it is not as effective as FTIR-ART. A similar experiment can be done on chemical extract got from the victim in order to detect any relationship between the lipstick got at the crime scene and the forensic results. One can detect chemicals used in manufacture of the lipstick using this method. The UV-Vis Spectrophotometry revealed the chemical composition of the samples tested. It is apparent that the method enables one to detect microscopic chemicals extracted from the victim.
In conclusion, the destructive and the non-destructive lipstick analysis methods can enable crime detectives to tract a victim of a given crime. The suitability of the lipstick analysis methods will depend on samples found at the crime scene. While methods such as thin layer chromatography would not reveal satisfactory results, the UV-Vis Spectrophotometry and FTIR-ART can reveal accurate chemical composition of the samples. The addition methods used in the analysis are vital for further comparison.
Bibliography
Blackledge, D. R. (2007) Forensic Analysis on the Cutting Edge: New Methods for Trace Evidence Analysis. New Jersey: John Wiley & Sons.
Chisum, J. W. and Turvey, E. B. (2011) Crime Reconstruction. Salt Lake City: Academic Press.
Mayo, W. D., Miller, A. F. and Hannah, W. R. (2004) Course Notes on the Interpretation of Infrared and Raman Spectra. New Jersey: John Wiley& Sons.
Salvador, A. and Chisvert, A. (2007) Analysis of Cosmetic Products. New York: Elsevier.
Severcan, F. and Haris, I.P. (2012) Vibrational Spectroscopy in Diagnosis and Screening. New York: IOS Press.
Wheeler, B. and Wilson, J. L. (2011) Practical Forensic Microscopy: A Laboratory Manual. New jersey: John Wiley & Sons.