Mass imaging of ketamine in a single scalp hair by MALDI-FTMS

Abstract

Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) coupled with mass spectrometry imaging (MSI) is a rapidly emerging technology that produces distribution maps of small pharmaceutical molecules in situ in tissue sections. Segmental hair analysis provides useful information regarding the state and history of drug use. A preliminary MALDI-Fourier transform ion cyclotron resonance (FTICR)-MSI method was developed for direct identification and imaging of ketamine in hair samples. After decontamination, the scalp hair samples from ketamine users were scraped gently and were fixed onto a stainless steel MALDI plate using double-sided adhesive tape. A Bruker 9.4 T solariX FTICR mass spectrometer with continuous accumulation of selected ions function was used in the positive ion mode. Four single hairs from the same drug abuser were analyzed. Three of four single hairs demonstrated ketamine spatial distribution, while only traces of ketamine were identified in the other one. The platform could provide detection power of ketamine down to the 7.7 ng/mg level in hair. MALDI-FTICR-MSI demonstrated the drug distribution over the whole hair length with higher spatial resolution compared with the traditional LC-MS/MS method after scissor cutting. Greater caution is needed in the interpretation of a single hair result because of the considerable variations in the growth rate and sample collection.

MALDI Imaging Mass Spectrometry Spatially Maps Age-Related Deamidation and Truncation of Human Lens Aquaporin-0

“…Images were acquired using a Smartbeam II 2kHz Nd:YAG (355 nm) laser using the small laser setting (estimated spot size~60 lm). Continuous accumulation of selected ions (CASI) 43 imaging also was used to achieve better sensitivity for lowabundance species. For CASI images, a narrow mass range around the signal of interest was selected (1475-3000 for m/z 2550) with a Q1 mass of 2555 and an isolation window of m/z 20.…”

Analysis of Antiretrovirals in Single Hair Strands for Evaluation of Drug Adherence with Infrared-Matrix-Assisted Laser Desorption Electrospray Ionization Mass Spectrometry Imaging

“…9 MSI analysis of hair strands using UV lasers, with depth penetration on the order tens of nanometers, 54 typically includes preprocessing steps to facilitate probing analytes localized within the cortex either through solvent extraction 25 or by longitudinally sectioning 27 and abraiding 28 individual strands to expose the cortex directly. These methods add both labor and time to the analysis process, while also introducing the potential for sample contamination 28 and analyte delocalization 25 that may compromise the temporal record of drug use. Given the greater penetration depth (micrometers) of IR lasers into biological samples, 54 we sought to develop an IR-MALDESI analysis method for hair that did not require sample manipulation.…”

Applications of MALDI Mass Spectrometry in Clinical Chemistry

“…amine (45 ). The analysis does require that the hair sample be cryogenically sliced to expose the pulp center, and thereafter chronological information is available.…”