Ion chromatography coupled to Q-Orbitrap for the analysis of formic and oxalic acid in beehive matrices: a field study

Icíar Beraza Gómez,Łukasz Rajski,Amadeo R Fernández-Alba,María José Gómez Ramos,Florencia Jesús,José Manuel Flores

doi:10.1007/s00216-022-03882-2

Icíar Beraza Gómez, Łukasz Rajski + Show 4 more

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https://doi.org/10.1007/s00216-022-03882-2

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Abstract

There is an increasing concern about the use of synthetic acaricides to fight the ectoparasitic mite Varroa destructor. Natural products such as formic acid (FA) and oxalic acid (OA) have emerged as a possible alternative control strategy. However, given the difficulty of analysing these highly polar compounds and the lack of robust and reliable methods, there are very few studies of the concentration and distribution of these natural acaricides in the beehive compartments. We present a reliable and simple analytical methodology, based on sample extraction with modified quick polar pesticide (QuPPe) methods followed by ion chromatography coupled to a quadrupole Orbitrap mass analyser for the analysis of FA and OA in honeybees, honey, beeswax, and beebread. The developed methods have been used in a field study for the evaluation of the presence and distribution of FA and OA in the beehive products, as well as in adult bees and bee brood samples, before, during, and up to 3 months after the application of the treatments by the beekeeper. Beebread and honey samples presented the highest concentration levels of OA and FA, respectively, mainly due to their natural presence. As expected, the organic acids showed low persistence in wax after the treatments. The natural acaricides were found in adult and developing bees at concentration levels below the reported LD50 in all the cases; however, residue levels of OA in larvae during the treatment application were very close to the reported LD50.Graphical abstract

Highlights

The western honeybee Apis mellifera ranks among the most important pollinators worldwide [1]
It has been reported a variety of methods for oxalic acid (OA) separation and detection, including spectrophotometry, hydrophilic interaction liquid chromatographic (HILIC), ion chromatography, chemiluminescence, and enzymatic methods based on oxalate oxidase and oxalate decarboxylase [28]
We present a new approach for the analysis of these compounds in beekeeping matrices, based on ion chromatography coupled to high-resolution mass spectrometry

Summary

Introduction

The western honeybee Apis mellifera ranks among the most important pollinators worldwide [1]. They do not seem to be toxic for humans, their possible effects on the quality of the products could be a reason of important concern; it has been demonstrated a change in the taste of honey due to the presence of thymol [16, 18] Organic acids such as FA (formic acid) and OA (oxalic acid) are the naturally occurring chemicals most used by beekeepers to fight the mite V. destructor. While accumulation in wax is unlikely due to the hydrophilic character of organic acids, residual contamination may occur in honey [5, 24] These organic acaricides have relatively low toxicity to bees, but excessive use by beekeepers can potentially lead to the weakening of the bee colony [25]. Ion chromatography with conductometric detection was used for the analysis of FA in bee honey [21]

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