Organic Compounds in Paper and Plastic Food Packaging

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Organic Compounds in Paper and Plastic Food Packaging
Li XIE1, a,*, Jiang YU1, b, Lu PEI1, c, Xing ZHOU1, d, Lu REN 1, e
1Institute of Printing and Packaging Engineering, Xi’ an University of Technology, Xi’ an, Shaanxi
710048, China
axnxieli@126.com, byupp@126.com, cpeilu11@126.com, dzhouxing61@163.com,
erenlu123@163.com
*Corresponding author
Keywords: Food Paper Packaging, Plastic Bag, Organic Compound.
Abstract. Additives, printing ink and other chemicals in packaging may influence safety of the food.
Standard solutions of eight organic compounds were prepared. By gas chromatography and mass
spectrometry technology, benzene, isopropyl alcohol, ethyl acetate, ethyl benzene, cyclohexanone,
m/p-Xylene, o-Xylene and butyl acetate in biscuit paper carton and jujube plastic bag were
determined and analyzed. Linear calibration curves of the eight compounds were obtained with
correlation coefficients of more than 0.9827, detection limits were in the range of 0.003-0.009 mg/m2,
recoveries ranged from 84% to 96% with RSD less than 3.8%. The results show that organic
compounds in biscuit paper carton and jujube plastic bag are respectively 0.266 mg/m2 and 0.37
mg/m2. Benzenes in the two packages are respectively 0.167 mg/m2 and 0.289 mg/m2. Content of
benzenes in the gravure printing inks used in the jujube plastic bag is obviously much more than that
in the offset printing inks used in the biscuit paper carton.
Introduction
Plastic is polymer material made from synthetic resin monomer as raw material, adding an
appropriate amount of stabilizers, plasticizers, antioxidant, coloring, pesticides and preservatives in
process [1]. Due to light weight, convenient transportation and sales, good chemical stability, easy
processing, good adornment effect and ideal protection effect, plastic packaging materials are widely
used in food industry. However, there are some problems in terms of health and safety in food plastic
packaging materials. The problems mainly are harmful monomer, oligomers, additives and organic
compounds produced in process. These poisonous and harmful chemical pollutants may dissolute and
migrate from packaging materials, resulting in contamination of food. Eventually, they may cause
harm to people’s physical and mental health.
During manufacturing process of paper packaging materials, there are wax, fluorescent whitening
agent, sizing agent, organic chloride, curing agent, fungicide, organic solvents and surfactant. These
compounds may migrate from materials to food.
There are a lot of harmful solvents such as benzene, toluene, xylene, ethyl acetate, butyl acetate,
isopropyl alcohol, n-propyl acetate and n-butyl acetate in solvent-based printing inks. Among them,
benzene solvents may cause greatest harm to human [2,3].
Scholars in domestic and foreign countries have made some researches on harmful compounds in
food packaging materials [4-13]. In this paper, a gas chromatography and mass spectrometry method
is used to analyze organic compounds in offset printed biscuit paper box and gravure printed jujube
plastic bag in order to manufacture safe and reliable food packaging.
Experiment
Sample Preparation
Biscuit paper box, white cardboard, offset printing ink: yellow ink, magenta ink, cyan ink and black
ink, fountain solution; jujube plastic bag, polyethylene (PE), polyester (PET), gravure printing ink:
International Conference on Material Science and Application (ICMSA 2015)
© 2015. The authors - Published by Atlantis Press
962

yellow ink, magenta ink and cyan ink, binder. These materials were provided by Xi’an ZhiCheng
packaging company. 5 cm×5 cm of packaging materials were clipped in accordance with location of
printing pattern, manually cut into strips with dimensions of 5 cm×0.5 cm. Then these strips were put
into headspace bottles. About 5 mg of printing ink, fountain solution and binder were put into
headspace bottles respectively. The headspace bottles were put into headspace equipment to test.
Chemicals and Standard Solutions
Benzene, isopropyl alcohol, ethyl acetate, ethyl benzene, cyclohexanone, m/p-Xylene, butyl acetate
and o-Xylene, (purity>99%, Tianjin, China) were prepared. Standard solutions of the eight reagents in
methyl alcohol at a series density of standard solution (0.01%, 0.02%, 0.04%, 0.05%, 0.06%, 0.08%,
0.1%) were obtained for external calibration.
Equipment and Chromatographic Conditions
Headspace gas chromatography and mass spectrometry system (Clarus 600, PerkinElmer, USA)
fitted with TurboMass software was used for experiment and data acquisition.
Balance temperature was 85℃, balance time was 40 min. Oven temperature was held at 35 ℃ for 6
min, then raised at 18 ℃/min up to 210 ℃; carrier gas, He (purity>99.999%) at a constant flow rate of
2.0 mL/min.
MS conditions were as follows: ion source temperature, 210 ℃; Interface temperatures, 220 ℃.
Quality scan range: m/z 35-400; ion source voltage, 70eV.
Results and Discussion
Determination of Standard Sample
Standard solutions of 1L were spiked into headspace bottles to test compound under the
experimental conditions. Fig. 1 shows retention time of isopropyl alcohol, ethyl acetate, benzene,
butyl acetate, ethyl benzene, m/p-xylene, o-xylene and cyclohexanone is respectively 1.79 min, 2.51
min, 3.03 min, 6.20 min, 6.86 min, 6.99 min, 7.31 min and 7.39 min. Peak area as vertical coordinate,
quantity concentration of compound as horizontal coordinate, regression equations of the eight
compounds were calculated. Linear calibration curves of the eight compounds were obtained with
correlation coefficients of more than 0.9827, detection limits were in the range of 0.003-0.009 mg/m2,
recoveries ranged from 84% to 96% with RSD less than 3.8%. The results are shown in Table 1.
Tab. 1 Regression equations, correlation coefficients, detection limits and relative standard deviations
of compounds
Compound
Regression
equation
Correlation
coefficient
Detection
limit (mg/m2)
Recovery
(%)
RSD (%)
Isopropyl
alcohol
y=532.45x-784.12
0.9896
0.004
91
2.5
Ethyl acetate
y=267.236x-34.56
0.9937
0.003
89
2.8
Benzene
y=38.74x-3681.4
0.9985
0.005
84
2.6
Butyl acetate
y=86.452x-542.52
0.9939
0.004
90
2.9
Ethylbenzen
e
y=134.257x-236.4
0.9827
0.006
87
3.8
m/p-Xylene
y=89.54x-5413.21
0.9864
0.005
85
3.2
o-Xylene
y=76.255x-453.9
0.9853
0.009
94
3.1
Cyclohexane
y=564.213x-541.8
0.9961
0.004
96
2.7
963

Fig. 1 Chromatogram of standard solution
Organic Compound in Food Packaging and Its Raw Materials
Chromatograms of paper carton and plastic bag are shown in Fig. 2 and Fig. 3. Content of the
compounds was calculated by regression equation. The results are shown in Table 2 and Table 3.
Tab.2 Organic compounds in the paper carton and its raw materials
Sample
Isopropyl
alcohol
Ethyl
acetate
Butyl
acetate
Benzen
e
Ethyl
benzene
m/p-
Xylene
o-
Xylene
Cyclohe
xanone
Amount
White
cardboard
(mg/m2)
0.050
0.047
0.002
0.014
0.045
0.051
0.092
-
0.301
Yellow ink
(mg/kg)
11.256
0.112
0.024
0.127
0.320
0.378
0.750
-
12.967
Magenta ink
(mg/kg)
3.400
0.080
0.026
0.333
0.233
0.260
0.630
-
4.962
Cyan ink
(mg/kg)
10.986
0.290
0.042
1.381
0.769
0.577
2.628
-
16.673
Black ink
(mg/kg)
18.490
0.341
0.095
0.372
1.170
1.006
1.974
-
23.448
Fountain
solution
(mg/kg)
102.237
0.150
0.016
0.073
5.223
1.051
2.441
-
111.191
Paper carton
(mg/m2)
0.055
0.042
0.002
0.011
0.038
0.040
0.078
-
0.266
-：No detected
Table 3 Organic compounds in the jujube plastic bag and its raw materials
Sample
Isopropyl
alcohol
Ethyl
acetate
Butyl
acetate
Benzene
Ethyl
benzene
m/p-
Xylene
o-
Xylene
Cyclohe
xanone
Amount
PET
(mg/m2)
0.042
0.016
0.002
0.007
0.018
0.019
0.020
-
0.124
PE (mg/m2)
0.042
0.018
0.002
0.007
0.019
0.022
0.026
-
0.136
Yellow ink
(mg/kg)
73.284
1637.4
51
37.612
35.235
40.746
33.847
77.493
-
1935.668
Magenta ink
(mg/kg)
141.271
442.16
6
8.737
3.254
0.085
205.37
6
0.067
2531.56
3332.516
Cyan ink
(mg/kg)
45.134
0.178
2.163
90.857
0.258
355.24
0
1348.7
18
-
1842.548
Binder
(mg/kg)
3.411
0.028
0.122
0.017
0.534
0.695
0.860
-
5.667
Plastic bag
(mg/m2)
0.042
0.037
0.002
0.011
0.050
0.056
0.172
-
0.37
-：No detected
Time (min)
Abundance (%)
, 06-Jul-2011 + 20:02:36
1.75 2.75 3.75 4.75 5.75 6.75 7.75 Time
0
100
%
1biaoyangdian25% 1: Scan EI+
TIC
5.28e8
3.03
1.79 2.51
6.99
6.20 6.86 7.39
7.31
50
964

Fig. 2 Chromatogram of paper carton
Fig. 3 Chromatogram of plastic bag
Analysis of Organic Compound in Food Packaging
Table 2 and table 3 show organic compounds in biscuit paper carton and jujube plastic bag are
spectively 0.266 g/m2 and 0.37 g/m2. Benzenes in the two packages are respectively 0.167 mg/m2 and
0.289 mg/m2. Benzenes in yellow, magenta, cyan and black offset printing ink are respectively 1.575
mg/kg, 1.456 mg/kg, 5.355 mg/kg and 4.522 mg/kg. Benzenes in yellow, magenta and cyan gravure
printing ink are respectively 187.321 mg/kg, 208.782 mg/kg and 1795.073 mg/kg. Content of
benzenes in gravure printing ink is obviously much more than that in offset printing ink. In addition,
white cardboard, PET, PE, fountain solution and binder contain different degree of benzenes.
Ways of Reducing Benzenes in Food Packaging
In paper and plastic packaging, benzenes exist in basic material, printing ink, fountain solution and
binder. Therefore, reducing benzenes organic compound mainly lays in the processing of raw
materials and improving production process.
Print Packaging with Water-based Ink. There are not volatile organic solvents in water-based
ink. So, printing with water-based ink can reduce residual toxicity in the printing products and make
printing equipment easy to clean. Moreover, it can reduce fire risk and hazards due to static electricity
and flammable solvents. Water-based ink is “green” printing material.
Print Paper Carton by Waterless Offset Printing Technology. Ink and fountain solution in
traditional offset printing technology contain various organic solvents. Waterless offset printing
technology commonly prints material with soybean oil ink and aromatic-free ink, which have no
impact on human and environment. So, waterless offset printing technology, prints with
non-solvent-based ink instead of fountain solution, make a great contribution to environment
protection.
Abundance (%)
Time (min)
, 13-Jul-2011 + 12:55:38
1.75 2.75 3.75 4.75 5.75 6.75 7.75 Time
0
100
%
hetiandazao 1: Scan EI+
TIC
8.06e7
5.24
1.52
2.06 2.60 3.02 4.05
6.25
6.13
5.51
6.55 6.987.30
50
Abundance (%)
Time (min)
, 12-Jul-2011 + 18:42:35
1.75 2.75 3.75 4.75 5.75 6.75 7.75 Time
0
100
%
zhiheyinwanhou 1: Scan EI+
TIC
1.12e8
5.24
1.77
2.59 3.92
3.03
5.96
6.99
6.19
7.30
50
965

Print Plastic Bag by Flexible Printing Technology. At present, food packaging in China is
mainly printed by gravure technology. Various food packaging bags in supermarket, such as biscuit,
pastry and milk powder packages, are basically printed with chlorinated polypropylene ink. While
flexible printing is a main method of food packaging in Europe and other countries. Flexible printing
is not as good as gravure printing in network performance. But it takes the lead in environment
protection. Flexible printing will gradually replace gravure technology in the future development.
Conclusions
Organic compounds in biscuit paper carton, jujube plastic bag and their raw materials have been
successfully analyzed by gas chromatography and mass spectrometry technology. Effective methods
to reduce benzenes in the food packages have been put forward from the aspect of material and
process.
Acknowledgment
This research was financially supported by the Foundation of Xi’an science and technology plan
project, China (Project No. CXY1433(7)).
References
[1] Y.W. Liao, G.R. Cao, W.C. Xu, Discussion on the food safety issue of the plasticizer in lid gasket,
Packaging Engineering, 29 (2008) 228-231.
[2] Z. Du, F.J Song, Discussion on relationship between hazard classification and health situation in
benzene workers of petro-chemical enterprise, Chinese Journal of Industrial Medicine, 28 (2015)
63-64.
[3] Y.M, Ding, D.J. Gong, M.H. Yang, Investigation on occupational hazard of benzene series in
industrial enterprises in Zhonglou District of ChangZhou City, Occupation and Health, 30 (2014)
2055-2057.
[4] S.H. Zhou, Q.B. Lin, B. Li, Determination of 18 substances in polypropylene food packaging
materials by gas chromatography-mass spectrometry, Packaging and Food Machinery, 33 (2015)
56-62.
[5] Y.N. Jiao, L. Ding, J.Y. Xiao, Simultaneous determination of multiple harmful substances in food
plastic packing materials by gas chromatography-mass spectrometry, Journal of Food Safety and
Quality, 4 (2013) 981-987.
[6] J. Muncke, Hazards of food contact material: food packaging contaminants, Encyclopedia of
Food Safety, 2 (2014) 430-437.
[7] M. Aznar, C. Domeno, C. Nerin, Set-off of non volatile compounds from printing inks in food
packaging materials and the role of lacquers to avoid migration, Dyes and Pigments, 114 (2015)
85-92.
[8] J.J. Zhu, J.E. Hill, Detection of escherichia coli via VOC profiling using secondary electrospray
ionization-mass spectrometry (SESI-MS), Food Microbiology, 34 (2013) 412-417.
[9] P. Trefz, S. Kischkel, D. Hein, Needle trap micro-extraction for VOC analysis: effects of packing
materials and desorption parameters, Journal of Chromatography A, 1219 (2012) 29-38.
[10] F. Biasioli, C. Yeretzian, F. Gaseri, PTR-MS monitoring of VOCs and BVOCs in food science
and technology, Trends in Analytical Chemistry, 30 (2011) 968-977.
966

[11] L. Xie, J. Yu, P.G. Ren, Analysis of volatile organic compounds in printing and plastic
packaging materials of instant noodles by headspace gas chromatography-mass spectrometry,
Chinese Journal of Analytical Chemistry, 39 (2011) 1368-1372.
[12] L. Xie, D.P. Jia, J.H. Ci, Analysis of volatile organic compounds in heatable plastic food
packages, Packaging Engineering, 35 (2014) 34-37.
[13] C.B. Liu, Z.H. Liu, Z.Y. Sun, Analysis of volatile organic compounds in food packing material
by purge & trap-gas chromatography, Modern Scientific Instruments, 4 (2010) 87-89.
967