QIMRBerghofer - Lipid quality score assessment against targeted plasma lipidomics data

Rapid assessment of lipidomics sample purity and quantity using attenuated total reflectance Fourier-transform infrared spectroscopy
  • Organism: Homo sapiens
  • Instrument: 6470A Triple Quadrupole LC/MS
  • SpikeIn: No
  • Keywords: lipidomics, lipids, phospholipids, sphingolipids, triglycerides, exosomes, FTIR, mass spectrometry, extracellular vesicles, chemical contaminants
  • Lab head: Michelle Hill Submitter: Thomas Stoll
Lipidomics is a rapidly growing technique in life science, biomedical research and biotechnology, with liquid chromatography-mass spectrometry (LC-MS) as the prevailing analytical method. Unlike other omics, quality assessment processes for lipidomic samples is not routinely carried out due to lack of accepted and validated methods. We investigated Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy (ATR-FTIR) as a rapid, sample-conserving method for assessment of lipid extract sample quality and quantity prior to LC-MS. FTIR spectra of pure lipid standards are characterized by CH-stretching (3,000 – 2,800 cm-1) and C=O (1,760 – 1,710 cm-1) vibrations which are quantitative in the range 40 – 3000 ng, with a limit of detection of 12 ng. While biphasic lipid extracts show similar spectra to pure lipids, monophasic extracts with metabolite contamination exhibit complex spectra which interferes with quantification by CH-stretching. Surprisingly, the widely used method of local baseline subtraction in FTIR spectral processing led to incorrect quantification. To facilitate sample quality screening, we used a spectral library of common contaminants to develop the Lipid Quality (LiQ) score, using a ratio of peak heights between CH-stretching vibrations maxima (2,922 cm-1) and the collective vibrations from amide/amine (1,645 cm-1), CH-stretching minima (2,888 cm-1) and sugar moieties (mix of COH and CO, 1,034 cm-1). Finally, we applied the method to a set of human plasma lipid extracts (n=107). Exclusion of poor-quality samples (n=25) based on LiQ score improved the correlation between the FTIR-calculated total lipid quantity and total intensity of LC-MS. With low sample (1 mL) and time (<5 minutes) requirements, ATR-FTIR spectroscopy with the LiQ score is an effective tool to support routine sample quality assessment in lipidomics
Created on 5/25/22, 7:56 AM
Clustergrammer Heatmap
191129GA_FTIR-Lipids_Plasma_dMRM_2022-05-25_10-58-12.sky.zip2022-05-25 07:55:58170266266266108