Efficiency of GC-MS method in detection of beeswax adulterated with paraffin

Abstract

A b s t r a c tThe efficiency of the gas chromatography -mass detector (GC-MS) technique for the detection of beeswax adulterated with paraffin, was evaluated. For this purpose, beeswax samples with paraffin additions (3, 5, 10, 30, 50%) were analysed. Since not enough is known about paraffin compositions, and since it is difficult to detect paraffin in beeswax, the aim of our research was also to compare the hydrocarbon composition of different types of paraffin. The analysis showed that the types of paraffin available on the market, differ qualitatively and quantitatively as far as their hydrocarbon compositions are concerned. In all kinds of paraffin, we found homologous series of n-alkanes that were much longer than those in beeswax. In beeswax, the amount of added paraffin that is possible to detect, differs and depends on the kind of paraffin used for adulteration. In this study, the minimum estimated percent that was detected using the GC-MS technique, was 3%. The adulteration is indicated by the presence of hydrocarbons containing over 35 carbon atoms in the molecule, and by the higher contents of n-alkanes (C 20 H 42 -C 35 H 72 ), in comparison to the concentration of these compounds determined in pure beeswax. We also presented the results of the quality control of commercial beeswax. Based on our results, it can be stated that beeswax adulteration is currently a problem. Keywords: adulteration, beeswax, detection, efficiency, GC-MS, paraffinResearch Institute of Horticulture, Apiculture Division in Puławy, Kazimierska 2, 24-100 Puławy, Poland INTRODUCTIONThe recent increased interest in the testing of beeswax composition and in the quality assessment of beeswax, is related to the numerous cases of beeswax adulteration. Substances such as ceresin, stearin, natural plant waxes (e.g. Candelilla wax, Carnauba wax), animal waxes and fats (e.g. lanolin, tallow), and mineral waxes (Montan, ozocerite) have been added to beeswax. It is paraffin, though, that is the product most frequently used for beeswax adulteration. Due to having a similar composition and similar physico-chemical properties, the addition of paraffin to beeswax, especially when added in small amounts, is difficult to detect (Bogdanov, 2009;Jimenez et al., 2009;Serra Bonvehi & Ornantes Bermejo, 2012;Maia, Barros, & Nunes, 2013;Svečnjak et al., 2015). The chemical composition of paraffin has not yet been sufficiently analysed. The information found in literature mostly concerned physicochemical properties (Bernal et al., 2005) or concerned the estimated data on the paraffin composition stated by the producers. From these data, it follows that the group of longstraight-chained saturated hydrocarbons (nalkanes) dominate in paraffin. The content of these hydrocarbons is estimated to be at different levels, and even at levels of up to 90%. Depending on the kind of paraffin (in particular the melting point of paraffin), and the purification level of the obtained product, the paraffin can also contain other hydrocarbons (e.g. branched, cyclic, unsa...

Identification and Quantification of Single and Multi‐Adulteration of Beeswax by FTIR‐ATR Spectroscopy

“…The LODs for paraffin (2.3%), stearic acid (1.2%), tallow (0.7%), and carnauba wax (3.1%) were calculated and lower than those estimated by other authors using FTIR‐ATR . The lowest detection limits published for GC‐MS or GC‐FID analysis are in the same range or even higher (paraffin 3%; stearic acid 1%; tallow 3%; carnauba wax 5%). Therefore, FTIR‐ATR spectroscopy is used not only for detection, but also for reliable quantification of beeswax adulteration.…”

“…While no standard method for authentication of beeswax in beekeeping is available, the identification of the hydrocarbons by gas chromatography (GC‐MS, GC‐FID) is recommended by commercial and official laboratories in Germany . Paraffin additives can be identified due to changes in the hydrocarbon level . Interpreting the degree of paraffin adulteration is problematic if the origin of the bees is not known.…”

“…Due to its lipophilic properties, varroacides as well as some pesticides accumulate in the beeswax . Moreover, a rising number of beeswax foundations adulterated with paraffin and/or stearic acid have appeared in the German and International market in the last years . These additives are considerably cheaper than beeswax, but diverse negative effects on bee colonies have been observed.…”

“…published an overview of GC coupled techniques and a detailed description of the methods proposed for standardization of the GC beeswax analysis. For detection of beeswax foundations adulterated with paraffin, intermediates or microcrystalline wax, the hydrocarbon content of the beeswax is usually analyzed by GC . However, natural variations in hydrocarbons, due to bee (sub)species or local conditions (e.g., nutrition of the colony), have to be considered .…”

Standard methods forApis melliferabeeswax research

“…Thermographic analysis of comb and hexagonal cell building (Bauer & Bienefeld, 2013). Methods for honey bee silk research employing various molecular, spectroscopic and chromatographic analytical tools (Campbell et al, 2014;Sutherland et al, 2007Sutherland et al, , 2011Sutherland et al, , 2014Walker, Warden, Trueman, Weisman, & Sutherland, 2013;;Weisman et al, 2010;Wittmer et al, 2011), and ESEM (Zhang, Si, Duan, & Wang, 2010). Method for research on thermal properties of beeswax based on classical melting point determination, determination of the heat of fusion, differential scanning calorimetry (DSC), and thermal conductivity determination (Buchwald et al, 2005;Buchwald, Breed, & Greenberg, 2008;Timbers & Gochnauer, 1982;Timbers, Robertson, & Gochnauer, 1977).…”