Stability and Recovery of Palytoxin and Ovatoxin‑a

TL;DR

This study examines how to best handle and preserve palytoxin and ovatoxin-a, marine toxins that can degrade during analysis, to improve their measurement and use in research.

Contribution

The study identifies optimal conditions for preserving palytoxin and ovatoxin-a during analysis to reduce degradation and improve recovery.

Findings

Palytoxin and ovatoxin-a degrade significantly when dried in glass vials with high aqueous solutions.

Using polypropylene vials and adding BSA and PBS reduces degradation and improves recovery.

Maintaining the toxins in solutions with >50% organic solvent and pH 5–8 minimizes losses.

Abstract

Palytoxin and ovatoxins
belong to a class of marine toxins identified
in soft corals and microalgae, Palythoa spp. and Ostreopsis spp., respectively.
Several documented events have resulted in human exposure to aerosolized
toxins that led to significant respiratory distress. It has been reported
that processing of samples containing palytoxin and ovatoxin during
analysis can lead to significant analyte recovery issues due to a
variety of parameters. In this study, systematically designed experiments,
monitored by LC–MS/MS, were used to evaluate palytoxin and
ovatoxin-a stability and recovery, and the effects of pH, solvent
composition, and vial contact surface. Significant losses of palytoxin
and ovatoxin-a were observed when drying highly aqueous solutions
in glass, which were reduced with the use of a polypropylene contact
surface and the addition of bovine serum albumin and phosphate-buffered
saline. The results showed that palytoxin analogues should be maintained
in solutions containing greater than 50% organic solvent, such as
methanol, and in a pH range of 5–8 in order to minimize losses
or degradation. The recovery of ovatoxin-a was lower than for palytoxin
in several experiments, indicating that the structural differences
between these analogues may affect solubility or stability. This work
provides insight into palytoxin and ovatoxin-a handling, and will
help improve analytical measurements, handling during toxicology studies,
and minimize losses during isolation protocols for the development
of reference materials.

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