Detection of lithium in scalp hair by time-of-flight secondary ion mass spectrometry with high energy (MeV) primary ions

Abstract

The application of MeV-SIMS is presented for the detection and mapping of lithium in chemically unprocessed, longitudinally sectioned scalp hair.

Ion Beam, Synchrotron Radiation, and Related Techniques in Biomedicine: Elemental Profiling of Hair

“…Since hair sample measurements is normally 1 hour, the hair chemical environment and morphology should remain unchanged. Scanning electron micrograph images further confirmed that the morphology of the analyzed samples remained unaltered after 1 hour of measurement with MeV-SIMS [53]. With particle-induced X-ray emission, however, a clear change in the sample's physical appearance can be noted when measuring for a longer time frame.…”

“…Another example includes the use of ion beam or synchrotron radiation analysis in epidemiological and etiological studies assessing exposure to toxic metals in vulnerable populations [14]. A recent exploratory study also pointed to the use of MeV-SIMS for the detection and mapping of the micronutrient lithium and its isotopes in longitudinally sectioned hair [53]. Lithium is an important psychopharmaceutical in the psychiatric community, and since it is quite challenging detecting the low Z element lithium that is present at trace levels in biological tissues, such analysis may find important application in monitoring medication adherence among psychiatric patients using hair.…”

“…The technique further allows for mass spectra to be extracted from an image region and vice versa to display the distribution of a secondary ion within the tissue. Interestingly, the technique is also able to analyze isotopic composition of light elements in a matrix such as hair [53]. The reader is, however, strongly recommended to first familiarize themselves with the experimental setup and a range of available detectors, the mechanism involved in secondary ion formation and the effect of the matrix composition on yield, as well as data processing and multivariate statistics deployed in SIMS before tackling this robust and challenging technique.…”

“…A single hair is laid in a groove of fitting depth, secured, and sectioned longitudinally with a stainless steel razor blade (Figure 1). The sectioned hair may be mounted on a silicon wafer with carbon tape (Figure 2) in the case of SIMS at MeV energies [53]. Alternatively, the hair may also be mounted intact in special holders, allowing analyses along the length of a hair.…”

Stigmatic imaging of secondary ions in MeV-SIMS spectrometry by linear Time-of-Flight mass spectrometer and the TimePix detector

“…As the samples should be prepared very thin (3-5 μm) to enable the penetration of the swift primary ions to the CEM detector, the continuous primary mode MeV-SIMS is not applicable on specific materials, i.e. human hair [29].…”