Next Article in Journal
Rethinking the Combination of Proton Exchanger Inhibitors in Cancer Therapy
Previous Article in Journal / Special Issue
Dynamics of Monoterpene Formation in Spike Lavender Plants
Article Menu
Issue 1 (March) cover image

Export Article

Open AccessArticle
Metabolites 2018, 8(1), 1; doi:10.3390/metabo8010001

Methanol Generates Numerous Artifacts during Sample Extraction and Storage of Extracts in Metabolomics Research

Center for Analytical Chemistry, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad-Lorenz-Straße 20, 3430 Tulln, Austria
These authors contributed equally to this work.
*
Author to whom correspondence should be addressed.
Received: 31 October 2017 / Revised: 15 December 2017 / Accepted: 18 December 2017 / Published: 22 December 2017
(This article belongs to the Special Issue Isotope Guided Metabolomics and Flux Analysis)
View Full-Text   |   Download PDF [2143 KB, uploaded 22 December 2017]   |  

Abstract

Many metabolomics studies use mixtures of (acidified) methanol and water for sample extraction. In the present study, we investigated if the extraction with methanol can result in artifacts. To this end, wheat leaves were extracted with mixtures of native and deuterium-labeled methanol and water, with or without 0.1% formic acid. Subsequently, the extracts were analyzed immediately or after storage at 10 °C, −20 °C or −80 °C with an HPLC-HESI-QExactive HF-Orbitrap instrument. Our results showed that 88 (8%) of the >1100 detected compounds were derived from the reaction with methanol and either formed during sample extraction or short-term storage. Artifacts were found for various substance classes such as flavonoids, carotenoids, tetrapyrrols, fatty acids and other carboxylic acids that are typically investigated in metabolomics studies. 58 of 88 artifacts were common between the two tested extraction variants. Remarkably, 34 of 73 (acidified extraction solvent) and 33 of 73 (non-acidified extraction solvent) artifacts were formed de novo as none of these meth(ox)ylated metabolites were found after extraction of native leaf samples with CD3OH/H2O. Moreover, sample extracts stored at 10 °C for several days, as can typically be the case during longer measurement sequences, led to an increase in both the number and abundance of methylated artifacts. In contrast, frozen sample extracts were relatively stable during a storage period of one week. Our study shows that caution has to be exercised if methanol is used as the extraction solvent as the detected metabolites might be artifacts rather than natural constituents of the biological system. In addition, we recommend storing sample extracts in deep freezers immediately after extraction until measurement. View Full-Text
Keywords: untargeted metabolomics; stable isotopic labeling (SIL); acidification; sample storage; plant metabolomics untargeted metabolomics; stable isotopic labeling (SIL); acidification; sample storage; plant metabolomics
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

Supplementary material

Share & Cite This Article

MDPI and ACS Style

Sauerschnig, C.; Doppler, M.; Bueschl, C.; Schuhmacher, R. Methanol Generates Numerous Artifacts during Sample Extraction and Storage of Extracts in Metabolomics Research. Metabolites 2018, 8, 1.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Metabolites EISSN 2218-1989 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top