Laser ablation electrospray ionization high‐resolution mass spectrometry for regulatory screening of domoic acid in shellfish

Abstract

RationaleDomoic acid (DA) is a potent neurotoxin that accumulates in shellfish. Routine testing involves homogenization, extraction and chromatographic analysis, with a run time of up to 30 min. Improving throughput using ambient ionization for direct analysis of DA in tissue would result in significant time savings for regulatory testing labs.MethodsWe assess the suitability of laser ablation electrospray ionization high‐resolution mass spectrometry (LAESI‐HRMS) for high‐throughput screening or quantitation of DA in a variety of shellfish matrices. The method was first optimized for use with HRMS detection. Challenges such as tissue sub‐sampling, isobaric interferences and method calibration were considered and practical solutions developed. Samples included 189 real shellfish samples previously analyzed by regulatory labs as well as mussel matrix certified reference materials.ResultsDomoic acid was selectively analyzed directly from shellfish tissue homogenates with a run time of 12 s. The limits of detection were between 0.24 and 1.6 mg DA kg−1 tissue, similar to those of LC/UV methods. The precision was between 27 and 44% relative standard deviation (RSD), making the technique more suited to screening than direct quantitation. LAESI‐MS showed good agreement with LC/UV and LC/MS and was capable of identifying samples above and below 5 mg DA kg−1 wet shellfish tissue, one quarter of the regulatory limit.ConclusionsThese findings demonstrate the suitability of LAESI‐MS for routine, high‐throughput screening of DA. This approach could result in significant time savings for regulatory labs carrying out shellfish safety testing on thousands of samples annually. © 2016 The Authors. Rapid Communications in Mass Spectrometry Published by John Wiley & Sons Ltd.

Metabolomic profiling of wild‐type and mutant soybean root nodules using laser‐ablation electrospray ionization mass spectrometry reveals altered metabolism

“…Successful relative quantitation of antibiotics in the presence of microbial metabolite gradients and an agar gel matrix was demonstrated (Li et al, 2016). Absolute quantitation of a neurotoxin in over 180 shellfish samples by LAESI-MS was demonstrated against regulatory laboratory results and certified reference materials (Beach et al, 2016).…”

Mass spectrometry based high-throughput bioanalysis of low molecular weight compounds: are we ready to support personalized medicine?

“…(D) Ionized analytes going through the mass spectrometer. (E) Example of differential breath analysis from Berchtold [ 75 ], reused with permission. On top, normal breath, and on bottom, breath spectrum after eating a chewing gum …”

Rapid quantitative screening of cyanobacteria for production of anatoxins using direct analysis in real time high‐resolution mass spectrometry

“…A number of different direct ionization techniques have been used to analyze phycotoxins. Recently, LAESI was used to quantitate domoic acid directly from shellfish homogenates 26,27 . In addition, condensed‐phase membrane introduction MS has been used to measure total microcystins in simulated algal blooms 28 .…”