TY - JOUR
T1 - Nanoextraction Coupled to Liquid Chromatography Mass Spectrometry Delivers Improved Spatially Resolved Analysis
AU - Lewis, Holly May
AU - Webb, Roger P.
AU - Verbeck, Guido F.
AU - Bunch, Josephine
AU - De Jesus, Janella
AU - Costa, Catia
AU - Palitsin, Vladimir
AU - Swales, John
AU - Goodwin, Richard J.A.
AU - Sears, Patrick
AU - Bailey, Melanie J.
N1 - Funding Information:
This study was possible due to an EPSRC strategic equipment award (EP/P001440/1), an EPSRC sponsored fellowship, EP/R031118/1, as well as the Research Council UK (Doctoral Training Partnership) studentship, EP/R513350/1.
Publisher Copyright:
Copyright © 2019 American Chemical Society.
PY - 2019/12/17
Y1 - 2019/12/17
N2 - Direct analyte-probed nanoextraction (DAPNe) is a technique that allows extraction of drug and endogenous compounds from a discrete location on a tissue sample using a nano capillary filled with solvent. Samples can be extracted from spot diameters as low as 6 μm. Studies previously undertaken by our group have shown that the technique can provide good precision (5%) for analyzing drug molecules in 150 μm diameter areas of homogenized tissue, provided an internal standard is sprayed on to the tissue prior to analysis. However, without an isotopically labeled standard, the repeatability is poor, even after normalization to the spot area or matrix compounds. By application to tissue homogenates spiked with drug compounds, we can demonstrate that it is possible to significantly improve the repeatability of the technique by incorporating a liquid chromatography separation step. Liquid chromatography is a technique for separating compounds prior to mass spectrometry (LC-MS) which enables separation of isomeric compounds that cannot be discriminated using mass spectrometry alone, as well as reducing matrix interferences. Conventionally, LC-MS is carried out on bulk or homogenized samples, which means analysis is essentially an average of the sample and does not take into account discrete areas. This work opens a new opportunity for spatially resolved liquid chromatography mass spectrometry with precision better than 20%.
AB - Direct analyte-probed nanoextraction (DAPNe) is a technique that allows extraction of drug and endogenous compounds from a discrete location on a tissue sample using a nano capillary filled with solvent. Samples can be extracted from spot diameters as low as 6 μm. Studies previously undertaken by our group have shown that the technique can provide good precision (5%) for analyzing drug molecules in 150 μm diameter areas of homogenized tissue, provided an internal standard is sprayed on to the tissue prior to analysis. However, without an isotopically labeled standard, the repeatability is poor, even after normalization to the spot area or matrix compounds. By application to tissue homogenates spiked with drug compounds, we can demonstrate that it is possible to significantly improve the repeatability of the technique by incorporating a liquid chromatography separation step. Liquid chromatography is a technique for separating compounds prior to mass spectrometry (LC-MS) which enables separation of isomeric compounds that cannot be discriminated using mass spectrometry alone, as well as reducing matrix interferences. Conventionally, LC-MS is carried out on bulk or homogenized samples, which means analysis is essentially an average of the sample and does not take into account discrete areas. This work opens a new opportunity for spatially resolved liquid chromatography mass spectrometry with precision better than 20%.
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U2 - 10.1021/acs.analchem.9b02821
DO - 10.1021/acs.analchem.9b02821
M3 - Article
C2 - 31747247
AN - SCOPUS:85076731552
SN - 0003-2700
VL - 91
SP - 15411
EP - 15417
JO - Analytical Chemistry
JF - Analytical Chemistry
IS - 24
ER -