Application of Gas Chromatography with the Mass Detector (GC-MS) Technique for Detection of Beeswax Adulteration with Paraffin

Abstract

A b s t r a c t To detect beeswax adulteration with hydrocarbons of alien origin (e.g. paraffi n), gas chromatography with mass detector (GC-MS) technique was used. The method has been verifi ed here on beeswax samples with different addition (3, 5, 10, 30, and 50%) of paraffi n and validated under the conditions of repeatability and within -laboratory reproducibility. The addition of paraffi n to beeswax can already be detected on the basis of an analysis of the chromatograms. The intensity of individual alkane peaks increased with the increase of the amount of paraffi n added to the beeswax. This increase was the mostly visible for the alkanes with even numbers of carbon atoms in the molecule: C 24 H 50 , C 26 H 54 , C 28 H 58 , C 30 H 62 , C 32 H 66 , and C 34 H 70 . These observations have also been proven by quantitative analysis performed using the internal standard method. Adding paraffi n to beeswax resulted in an increase in the total contents of n-alkanes as well as individual alkanes, and in particular, of the even-numbered alkanes. The addition of paraffi n to beeswax also resulted in the appearance of alkanes containing over 35 carbon atoms in the molecule, which were not detected in beeswax. The method for determination of beeswax hydrocarbons with the GC-MS technique is characterised by satisfactory repeatability and within-laboratory reproducibility. This method can be used for the detection of beeswax adulteration with hydrocarbons of alien origin (e.g. paraffi n).Keywords: adulteration, beeswax, GC-MS, hydrocarbons, n-alkanes, paraffi n.Research Institute of Horticulture, Apiculture Department, Puławy, Poland INTRODUDCTIONDue to the insuffi cient domestic production of beeswax and the lack of obligatory legal regulations concerning beeswax quality, instances of its adulteration are quite frequent. The addition of alien substances such as paraffi n, decreases beeswax quality as well as the quality of the foundation made of such adulterated beeswax. As a consequence, it may no longer be possible to use this product in beekeeping. It may also not be possible to use such a product in some branches of industry, for example, the cosmetic, pharmaceutical, and food industry. The sensory assessment and physico-chemical characterisation are only approximate and do not allow to detect the adulteration of beeswax unambiguously. Beeswax which has paraffi n added, becomes chinawhite and pliable when kneaded with the fi ngers. What is more, the addition of paraffi n causes the beeswax to become smooth and shiny where rubbed (Curyło, 1983). As we mentioned previously (Waś et al., 2014a), a lot of methods so far used for the determination of hydrocarbons in beeswax and for the detection of beeswax adulteration were based on the physico-chemical parameters. These parameters include: melting point, density, solubility, and saponifi cation, acid and ester numbers, and iodine index (Tulloch, 1973;Serra Bonvehi et al., 1989;Serra Bonvehi, 1990;Vit et al., 1992;Poncini et al., 1993). Some interrelations were found be...

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

“…5 and 6% in beeswax obtained from light and dark coloured combs, respectively (Waś, Szczęsna, & Rybak-Chmielewska, 2014b). The higher content of even-numbered alkanes in the paraffin, was reported in our previous work (Waś, Szczęsna, & Rybak-Chmielewska, 2015) as well as by other authors (Jimenez et al, 2009;Serra Bonvehi & Ornantes Bermejo, 2012). Moreover, the content of linear alkanes determined in the current work suggests that besides this group of hydrocarbons, other compounds belonging to other homologous series (e.g.…”

“…The current studies on paraffin composition have shown that those paraffins available on the market, differ not only in physico-chemical properties but also in the qualitative and quantitative composition of the hydrocarbons. In all types of paraffin, the identified homologous series of n-alkanes were much longer (containing over 35 carbon atoms in the molecule) than in beeswax, as was previously reported (Jimenez et al, 2009;Serra Bonvehi & Ornantes Bermejo, 2012;Waś, Szczęsna, & Rybak-Chmielewska, 2015). We did not find hydrocarbons containing below 20 carbon atoms in the molecule as had been mentioned by other authors, that may be included in some paraffin types (Szpyrka, 1999;Jimenez et al, 2004;Serra Bonvehi & Ornantes Bermejo, 2012).…”

“…In the previous work (Waś, Szczęsna, & RybakChmielewska, 2015) we tested just one type of paraffin with the total content of n-alkanes (C 20 H 42 -C 40 H 82 ) amounted to 68.42 g/100 g, and beeswax mixture with different additions (3, 5, 10, 30, 50%) of this type of paraffin. Based on the results obtained for the basic parameters of validation (repeatability, within-laboratory reproducibility, and recovery) presented in previous paper (Waś, Szczęsna, & Rybak-Chmielewska, 2015) we found that the GC-MS method can be used for detection of beeswax adulteration with hydrocarbons of alien origin (e.g. paraffin).…”

“…There are differences in the paraffin composition and its difficult to detect, especially small amounts of paraffin added to beeswax. For these reasons, the studies with beeswaxparaffin mixtures initiated previously (Waś, Szczęsna, & Rybak-Chmielewska, 2015), were extended here to include mixtures with other types of paraffin. Based on the results obtained for beeswax with different additions of varied types of paraffin, we estimated the efficiency of the method for detection of beeswax adulteration with paraffin.…”

“…In the laboratory, virgin beeswax was adulterated with 3, 5, 10, 30, and 50% additions of paraffin LTP 56/25 and PW 573, as was described previously (Waś, Szczęsna, & Rybak-Chmielewska, 2015). These samples were used to evaluate the suitability of the GC-MS method for detecting beeswax adulterated with paraffin, and for estimating the minimum percentage of paraffin that can be detected in beeswax by GC-MS.…”