Persistence of transferred fragrance on fabrics for forensic reconstruction applications

It has recently been established that volatile organic compounds (VOCs) successfully transfer between clothing even with a short contact of 10 s, highlighting the potential to use VOCs in forensic reconstruction scenarios, such as sexual assault cases. The mid and low volatility compounds transferred in greater amounts than high volatility compounds. This study presents empirical data addressing the persistence of transferred VOCs on clothing for the first time. A series of experiments were carried out to determine the persistence of VOCs on clothing for time periods of up 4 weeks, on natural and synthetic fibres, and at three different environmental temperatures. The data indicate that the highest VOC amounts are generally obtained for shorter persistence times of up to 1 d. Whilst high volatility compounds were not recovered in sufficient amounts to allow quantification, the four other transferred VOCs were successfully quantified for persistence times of up to 4 weeks. The persistence for mid-volatility compounds follows decay curve trends in line with those previously obtained for fibres, glass and pollen. When comparing the persistence of VOCs on a natural and a synthetic fibre, for a persistence time of 1 h, the transferred VOCs were retained on a natural fibre in higher amounts than on a synthetic fibre. However, for longer persistence times the concentration of VOCs was similar between the two fabrics. Lastly, lower environmental temperatures resulted in higher recoveries for most VOCs, especially for short persistence times. These findings demonstrate that optimal recovery of VOCs from clothing occurs when the fabric is kept at cooler temperatures and analysed soon after the fragrance transfer occurred, although VOC recovery was possible at higher temperatures and after longer persistence times. Given the transfer and persistence characteristics of VOCs from fragrance, there is potential for fragrance to be used as a form of trace in forensic reconstruction approaches

Development of a HS-SPME/GC-MS method for the analysis of volatile organic compounds from fabrics for forensic reconstruction applications.

An analytical method for the determination of trace amounts of volatile organic compounds (VOCs) relevant to the cosmetics industry was optimised, validated and employed for the analysis of commercial perfumes. The method used a combination of headspace solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS). In addition to fibre type, three different HS-SPME extraction conditions were investigated simultaneously, namely incubation time, extraction time and extraction temperature, using a central composite design in order to determine the optimal conditions for the extraction of VOCs of interest. The main figures of merit of the proposed method (calibration range, limits of detection and quantification, trueness and precision) were evaluated for six different VOCs in both natural and synthetic fibres in order to validate it and verify its capability for the proposed application. The validated method was applied for the analysis of traces of commercial perfumes from fabrics, and the VOCs of interest were successfully quantified. This simple, highly sensitive, and robust method has the potential to represent a powerful approach for forensic reconstructions where perfumes have transferred between individuals, such as during assaults and sexual assaults

Estimated Exposure Risks from Carcinogenic Nitrosamines in Urban Airborne Particulate Matter

Organic nitrogen (ON) compounds are present in atmospheric particulate matter (PM), but compared to their inorganic, hydrocarbon and oxygenated counterparts, they are difficult to characterize due to their complex chemical composition. Nitrosamines are a class of ON compounds known to be highly carcinogenic, and include species formed from nicotine degradation, but there are no detailed estimates of their abundance in ambient air. We use a highly sensitive analytical method, which is capable of separating over 700 ON compounds, to determine daily variability in nicotine, and 8 non specific and 4 tobacco specific nitrosamines in ambient PM from central London over two periods in winter and summer. The average total nitrosamine concentration was 5.2 ng m-3, substantially exceeding a current public recommendation of 0.3 ng m-3 on a daily basis. The lifetime cancer risk from nitrosamines in urban PM exceeded the U.S. Environmental Protection Agency guideline of 1 excess cancer cases per 1 million population exposed after 1 hour of exposure to observed concentrations per day over the duration of an adult lifetime. A clear relationship between ambient nitrosamines and total PM2.5 was observed with 1.2 ng m-3 ± 2.6 ng m-3 (total nitrosamine) per 10 µg m-3 PM2.5