foram®3:
Using Raman Spectroscopy to Discriminate Lipsticks
Lipstick stains are sometimes encountered as physical evidence at crime scenes or from the clothing of a suspect. Conventional methods of analysis of lipsticks include visual comparisons, thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). These techniques are either subjective, destructive or a combination of both.
Constituents of lipstick include a mixture of castor oil, beeswax, carnauba wax and lanolin (typically making up 95% of the lipstick). The remainder consists of soluble and insoluble dyes, pigments and perfumes[1].
Here we present a brief study applying Raman spectroscopy to the discrimination of lipsticks.
The lipstick samples used in this study are listed in Table 1 below.
All spectra were recorded using the FORAM Raman spectrometer (Foster and Freeman Ltd, UK), running at 785 nm. Each spectrum was run on full power (~2.8 mW). Each spectrum consisted of 6 averaged scans. The integration time for each scan was 1 minute or 30 seconds.
All Spectra were baseline corrected using a propriety (Foster and Freeman) fluorescence filter.
| Lipstick Sample | Colour |
| L’Oreal Infallable 304 | Pink |
| Collection 2000 – Blossom | Pink |
| 170 Alarm | Red |
| Double Intrigue – Rose | Pink |
| No.7 – Clover Pink | Pink |
| Classic Sorbet | Pink |
Table 1 Lipsticks used in this study.
Figure 1 shows a range of spectra of the samples used in this study.
Whilst there are some aspects of the spectra that are similar there are clear differences between each of the spectra. Visual comparison of the samples gave a discrimination power of 100%.
It has been shown that using Raman spectroscopy at 685 nm it is possible to discriminate lipsticks, which gave a discrimination power of 100%.
[1] A.M.L. Barker and P.D.B. Clarke, Forensic Science Society, Vol.12, 1972, 449.