Journal of Chromatography B, 879 (2011) 2897–2901 Contents lists available at SciVerse ScienceDirect Journal of Chromatography B j ourna l ho me page: www.elsevier.com/locate/chromb Analysis of cantharidin in false blister beetles (Coleoptera: Oedemeridae) by headspace solid-phase microextraction and gas chromatography–mass spectrometry Ali Mehdinia a,∗ , Mina Asiabi b , Ali Jabbari b , S. Mohammad Abtahi c a Department of Marine Living Resources, Iranian National Institute for Oceanography, Tehran, Iran b Department of Chemistry, K.N. Toosi University of Technology, Tehran, Iran c Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran a r t i c l e i n f o Article history: Received 13 December 2010 Accepted 13 August 2011 Available online 22 August 2011 Keywords: Solid-phase microextraction Cantharidin False blister beetle Oedemeridae a b s t r a c t A headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography–mass spectrom- etry (GC–MS) method was developed to determine a type of terpenoid named as cantharidin in the false blister beetles, family Oedemeridae. The experimental parameters for HS-SPME method were optimized. Six commercial fibers for HS-SPME method development were tested and the divinylben- zene/carboxene/polydimethylsiloxane fiber was selected to provide the best detection of analyzed compound. The calibration curve showed linearity in the range of 0.1–50 g mL -1 , correlation coeffi- cient (R 2 = 0.992), limit of detection (0.01 ng mL -1 ) and quantitation (0.04 ng mL -1 ) were obtained for the proposed method. The relative standard deviations of intra-day and inter-day assays were 7.8 and 3.4%, respectively. The recovery values, obtained after spiking the beetle samples by three concentration levels of standard solution, were higher than 87%. The results indicated the successful application of the proposed method on the analysis of cantharidin from the false blister beetles. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Biological samples, such as plasma, whole blood, urine and tis- sue are exceedingly complex mixtures that contain hundreds or thousands of components including salts, proteins, cells and exoge- nous and endogenous small organic molecules. Determination of selected analytes of interest in such a complex matrix cannot usually be performed without appropriate sample preparation prior to the analysis, even when using powerful modern ana- lytical instrumentation, such as liquid chromatography–tandem mass spectrometry (LC–MS/MS) [1]. Although solvent extraction of biological materials may be effective for obtaining an apprecia- ble fraction of natural products present in biological tissue, the headspace analysis provides a more representative sampling of volatile organic compounds (VOCs). Solid-phase microextraction (SPME), introduced by Pawliszyn and co-workers [2,3], is a fast, simple, easy to prepare, inexpen- sive and solvent free extraction technique [4,5]. Recently, SPME has been widely adopted as a reliable and rapid alternative tech- nique giving similar qualitative and quantitative results to those obtained by conventional solvent-extraction methods. Headspace- ∗ Corresponding author. Tel.: +98 21 66944873; fax: +98 21 66944869. E-mail addresses: mehdinia@inio.ac.ir, mehdi 3848@yahoo.com (A. Mehdinia). SPME (HS-SPME) has a great potential in the analysis of VOCs emissions [6–11]. VOCs of insects can be used as a chemical defense mechanism against predator species. By improving the extraction procedure of the analytes from insect’s matrix, it may be possi- ble to apply HS-SPME for the detection of very small amounts of VOCs that may be present in the insects. The first report of SPME being used to analyze the released compounds from the insects (i.e. pheromones), by using of polydimethylsiloxane (PDMS) fiber, was appeared in 1995 [12]. Cantharidin or 2,3-dimethyl-7-oxabicyclo [1,2,2] heptane-2,3- dicarboxylic anhydride (Fig. 1) is a monoterpene anhydride molecule which release from the false blister beetles during defense. Its mode of action is the inhibition effect on protein- phospatase 2A (PP2A), an enzyme that operates in the metabolism of glycogen [13,14]. Cantharidin can cause severe skin blisters espe- cially when the insects discharge it from their junctions as a defense system or when they are crushed on the body. Only two families of beetles have been recognized as cantharidin producer in ani- mal kingdom heretofore. These are Meloidae and Oedemeridae that are known as blister beetles and false blister beetles, respectively [15]. Furthermore, cantharidin has important antitumor proper- ties and has been used as an anticancer agent for the treatment of hepatoma and oesophageal carcinoma. Recently, cantharidin has also been used typically (0.7%) in the treatment of warts [16,17]. 1570-0232/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.jchromb.2011.08.020