A rapid analytical method for hair analysis using ambient pressure ion mobility mass spectrometry with electrospray ionization (ESI-IMMS)

Analysis of hair is often applied to assess drug abuse history, exposure to environmental and industrial pollutants, heavy metals, gestational drug exposure and various other screening purposes. This manuscript reports the application of ambient pressure ion mobility spectrometry mass spectrometry (IMMS) with electrospray ionization (ESI) source as a rapid analytical tool for hair analysis. The study demonstrated that ion mobility spectrometry (IMS) as a pre-separation technique prior to analysis by mass spectrometry (MS) provides detection and determination of compounds of interest present in hair at nano-molar concentration level. After extraction of analytes from hair, the ESI-IMMS method of analysis does not require the derivatization or sample treatment that is often required for other separation methods such as gas chromatography. One advantage of IMS over chromatography separation is that resolving powers are similar to those in GC and much greater than those possible by liquid chromatography. In addition, separation speed is faster than both gas and liquid chromatographic methods. Four of the nine hair samples anonymously donated by customers at a local hair salon tested positive for caffeine and two of the four samples that tested positive for caffeine also tested positive for nicotine. A positive response based on mass analysis for methamphetamine was obtained for one of the hair samples. Further investigation using the mobility data demonstrated that the response was a false positive and that it may have occurred from the use of a hair gel. This article reports the potential of IMMS as an analytical technique for rapid and routine screening of hair samples, cosmetics, and pharmaceuticals.