Determination of the fungicide vinclozolin in honey and bee larvae by solid-phase and solvent extraction with gas chromatography and electron-capture and mass spectrometric detection

Multiresidue method for trace pesticide analysis in honeybee wax comb by GC-QqQ-MS

The aim of this analytical study is to develop an improved multi-residue methodology of high sensitivity and expanded scope for pesticide residue analysis in honeybee wax combs. The method was validated for 160 pesticide residues (including acaricides, insecticides, fungicides and herbicides) gas chromatography amenable and covering a wide variety of polarity and chemical structure. This method of analysis applied gas chromatography coupled to a triple quadrupole mass spectrometer for the quantitative analysis of pesticide residues. The extraction procedure applied was based QuEChERs method allowing acceptable recoveries for most of the pesticides (98%), within the range 60-120% with an associated precision (RSD) <20%, at concentration levels of MQL of 10µgkg^-1 for all pesticides with the exception of 3,5-dichloroaniline and chlordane (20µgkg^-1). The expanded uncertainty of the results was ±35% on average (coverage factor k=2 for a confidence level of 95%). The chromatographic multi-residue method was applied to determine levels of pesticide residues in 50 honeybee wax comb samples randomly collected from different apiaries in Spain. A total of 32 pesticide residues (14 insecticides/acaricides, 10 insecticides, 6 fungicides and 2 herbicides) were detected in the samples. The highest pesticide concentrations were found for those with insecticide-acaricide activity like acrinathrin, chlorfenvinphos, coumaphos and fluvalinate-tau, some of them are mainly applied in apiculture for controlling the honeybee parasite Varroa destructor. The total load of pesticide residues ranged from 69 to 1000µgkg^-1 for 40% of the analysed samples, 22% contained pesticide residues in the ranges of 1000-2000µgkg^-1, 24% between 2000 and 5000µgkg^-1 and 14% of the samples contained residues between 5000 and 9557µgkg^-1.

Analytical methods for pesticide residue determination in bee products

Monitoring pesticide residues in honey, wax, and bees helps to assess the potential risk of these products to consumer health and gives information on the pesticide treatments that have been used on the field crops surrounding the hives. The present review seeks to discuss the basic principles and recent developments in pesticide analysis in bee products and their application in monitoring programs. Consideration is given to extraction, cleanup, chromatographic separation, and detection techniques.

Determination of rotenone residues in raw honey by solid-phase extraction and high-performance liquid chromatography

A method for determining residues of the insecticide rotenone in raw-honey by high-performance liquid chromatography (HPLC) is described. To extract the residues, organic solvents such as ethyl acetate, n-hexane/dichloromethane and solid-phase extraction with octadecylsilane cartridges or Florisil packed columns were tested. Determination was carried out by reversed-phase HPLC using acetonitrile-buffer phosphate (pH 7) (60:40, v/v) as mobile phase and detection at 210 nm. Although the data showed that the two extraction methods were able to isolate the pesticide residues, the extraction on octadecylsilane cartridges was preferred due to its simplicity and higher recovery. Recoveries depended strongly on the fortification level for the two extraction procedures. Practical determination limits of 0.015 mg/kg were obtained. In the analysis of honeys, from beehives treated with rotenone at therapeutical doses for 1 month, residual amounts below 0.2 mg/kg were found.

Solid-phase microextraction applied to the analysis of pesticide residues in honey using gas chromatography with electron-capture detection

The possibilities of using solid-phase microextraction to determine residues of pesticides in honey have been examined. For this purpose, three types of fiber have been assayed: polyacrylate of 85 microns thickness, and polydimethylsiloxane of 7 and 100 microns thickness. They have been applied to the extraction of 21 pesticides of different chemical families. The effects of the temperature, extraction time and ionic strength on the microextraction have been studied, proposing the most adequate for each fiber. Under optimized conditions, precision, intervals of linearity and detection limits were evaluated.

Gas chromatography with electron-capture and nitrogen-phosphorus detection in the analysis of pesticides in honey after elution from a Florisil column. Influence of the honey matrix on the quantitative results

A modified procedure to extract pesticides from honey samples that involves loading the honey onto a Florisil packed column and subsequently eluting it with an n-hexane-dichloromethane mixture is proposed. Anomalous high gas chromatographic responses and subsequently very high recoveries for the pesticides in the extracts were obtained by a conventional calibration with pesticide solutions in organic solvent. This effect was attributed to the honey matrix and can be circumvented by using spiked honey extracts as calibration standards.