Abstract : The volatile components in the inks of different case skins were extracted by solid-phase microextraction (SPME), analyzed by GC/MS, and quantified by GC. Several typical cigarette case skins were compared and analyzed. The best sampling conditions were compared with the sampling effects of three different types of fiber heads, and the identified major components were analyzed.
Key words: solid-phase microextraction; GC/MS; GC; cartridge; ink; volatile
With the increasingly fierce competition in the tobacco industry, improving the quality of decoration of cigarette products has become an important means for manufacturers to increase their product competitiveness. At the same time, the side effect is that if the ink of the packaging material is not handled properly, there will be a large amount of odor and even harmful residual substances entering the cigarette, which will affect the inherent quality of the cigarette and even endanger the health of the human body. In order to understand the current situation of cigarette packaging materials at home and abroad, we used solid-phase microextraction combined with GC-MS to detect and analyze a large number of packaging materials at home and abroad, and studied and improved the sampling conditions of SPME . This article will describe how to use the SPME-GC-MS method to detect the volatile components of packaging materials from the characteristics of the fiber head , sample dosage, equilibrium temperature and equilibrium time, and several representative cigarettes. The packaging materials were compared and analyzed to provide an important reference for the quality control of packaging materials.
2. Experimental part
2.1 Materials and Instruments
Materials: Domestic cigarette packaging materials with different grades, and imported cigarette packaging materials such as â€œ555â€, â€œMarlboroâ€ and â€œMILD SEVENâ€;
Instruments: Solid-phase microextraction handle and 100um polydimethylsiloxane (PDMS), 65um ethylene glycol-divinylbenzene copolymer (CW-DVB) and weak polar PDMS/DVB extraction fiber head (both For the United States Supelco products);
Agilent 5973N GC/MS.
Agilent 6890 Gas Chromatograph with FID Detector.
2.2 SPME sampling conditions
Sampling bottles are sealed with a Teflon-lined silicone rubber mat and equilibrated at 100Â°C for more than 2 hours to fully remove the volatile components in the bottles; aging the solid-phase microextraction fiber heads according to the corresponding aging conditions, and then clipping About 0.5 grams of the sample on different parts of the packaging material was loaded in a special SPME sampling bottle, and the SPME fiber head was inserted into the headspace at 100Â°C for 15 minutes and then equilibrated at 40Â°C for 15 minutes.
2.3 GC/MS Analysis
HP-5MS quartz capillary column; carrier gas high-purity He; carrier gas flow 1.0ml/min; inlet temperature 250 Â°C; program temperature: 40 Â°C, hold 2min, to 3.5 Â°C / min to 250 Â°C, hold 10min; Splitless injection without splitting time 3 min; liner using Supelco glass liner with 0.75 mm ID, desorption time 5 min; injection volume 1 ul; GC/MS transmission line temperature 280 Â°C, mass scan range 35-400 u, EI ion Source temperature 230Â°C, quadrupole temperature 150Â°C, EI ionization energy 70ev. The collected mass spectra were retrieved using the WILY library.
2.4 GC Analysis
HP-5 quartz capillary column; carrier gas high purity hydrogen; carrier gas flow 1.0ml/min; inlet temperature 250Â°C; program temperature: 40Â°C, hold 2min, rise to 250Â°C with 3.5Â°C/min, hold for 10min; Sample injection, without split time 3 min; detector temperature 300 Â°C; liner using 0.75mm diameter Supelco glass liner, desorption time of 5min; injection volume 1ul.
Because the CW/DVB fiber coating is not cross-linked, the coating is very fragile and easily damaged. Therefore, special attention must be paid when using the CW/DVB fiber coating. Do not touch the sample or other objects, especially check the presence of septum fragments in the liner. To prevent damage to the fiber head coating due to friction during the injection process.
3. Results and discussion
3.1 Comparison of Three Extraction Fiber Heads
Using 100umPDMS, 65umPDMS/DVB, and 65umCW/DVB fiber heads, headspace sampling of sample 1 was performed according to the sampling conditions in 2.2. The GC chromatograms obtained with the three fiber heads are shown in Fig. 1, Fig. 2, and Fig. 3, respectively. Show:
The experimental results show that non-polar 100um PDMS fiber heads are useful for non-polar, weakly polar, or lipophilic components such as alkanes, limonenes, higher fatty acids and their esters, alkaloids, ketones, triacetin, and menthol. High sampling sensitivity because they are easily adsorbed by non-polar liquid film; 65um CW-DVB fiber tip has higher sensitivity to polar compounds such as lower fatty acids, aromatic acids, alcohols, glycols, aromatic alcohols, phenols, miscellaneous Cyclic compounds, they all have strong polarity, some compounds are also very water-soluble and easily adsorbed by polar liquid membranes; 65um PDMS/DVB is a weakly polar fiber head, for polar and non-polar groups The points have strong adsorption, but the selectivity is poor, there are many peaks in the spectrum, and there are many interference components. Many of the analyzed components such as paraffins do not have much value in the quality monitoring of packaging materials. Since some of the benzene derivatives and alcohols are the polar compounds we are analyzing, the spectrum obtained by using CW/DVB fiber heads has a stable baseline, few interference components, and important components in the composition can be identified. The CW/DVB fiber tip method can be basically identified using the components that can be identified from the PDMS fiber tip, but differs only in the peak strength and the PDMS fiber tip acquires significantly less information than the CW. /DVB fiber head, PDMS/DVB fiber head is not suitable because of its poor selectivity. Therefore, based on the above analysis, we decided to use a 65um CW/DVB fiber head for sampling.
3.2 Selection of equilibrium time and equilibrium temperature
In the experiment, we first sampled in the headspace at 100Â°C for 15 minutes, then sampled at 40Â°C for 15 minutes, and sampled at 100Â°C. The volatile components in the sample could be volatilized and adsorbed by the fiber head. The temperature was too high. Will damage the fiber head; too low, some volatile substances can not be completely volatile, affecting the adsorption effect. The equilibration at 100Â°C for 15 min is to achieve a sufficient balance between the volatile material and the fiber head; sampling at 40Â°C for 15 min is to allow the volatile substances, especially the low-boiling substances, to reach the balance of adsorption and desorption on the fiber head at low temperature. Finally, the gas-sample-fiber heads are balanced to achieve the best adsorption effect. When equilibrated directly at room temperature, the adsorption effect of the fiber head is affected, and it is difficult to obtain the best results.
3.3 sample analysis
In this experiment, we conducted a comparative analysis of dozens of representative cigarette packaging materials and illustrated them by the following representative cigarettes of three different grades. Sample 2 was an imported famous brand cigarette â€œ555â€ and sample 3 For domestically produced high-grade cigarettes, sample 4 is domestically produced mid-range cigarettes:
From the experimental results, we found that the peaks in the spectra of foreign brand cigarette packs were mainly generated from tobacco, mouth sticks, flavors and fragrances, the volatile components of the paper itself, and the volatile components in the packaging glue adsorbed on the packaging materials. The low content is basically harmless and will not have any impact on the aroma of cigarettes. In domestic cigarettes, the box skins of some high-end branded cigarettes are similar to those of foreign brand cigarettes, but some high-end domestic cigarette boxes contain some Factors that affect the internal quality of cigarettes or harmful to the human body can be divided into three major categories: one is benzene and toluene, naphthalene and other benzene derivatives, which are harmful to humans, the second is the two phenyl Ketones and other aldehyde and ketone compounds, although they do not have a strong odor, react with some components of cigarettes (such as propylene glycol) to generate substances with strong odors, which adversely affect the inherent quality of cigarettes. Classes are substances that have very strong odors themselves, such as succinic acid dimethyl fat, benzoic acid methyl ester, glutaric acid dimethyl fat, p-methoxy phenol, etc. Gas adversely affected, resulting aroma of discomfort and even cause odor. There are many kinds of these components, and the content is also high. They mainly come from the ink on the packaging material and the organic solvent used. Based on the above analysis, it can be seen that compared with the imported brand cigarettes, the domestic famous brand cigarettes have a large gap with the foreign well-known brands in terms of the safety and usability of the packaging materials, apart from the difference in the quality of the cigarette products. With China's accession to the WTO, in order to resist the offensive of imported cigarettes, in addition to making a fuss about improving the quality of cigarette products, we must also make greater efforts to improve the safety of cigarette-related products, especially packaging materials. Otherwise, we will The competition is in a disadvantageous position. At the same time, it is hoped that the relevant departments will formulate relevant standards for the safety of cigarette packaging materials as soon as possible, and promote the industryâ€™s attention to the safety of packaging materials so as to increase the competitiveness of the entire industry.
China Chromatography Network
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