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食品安全国家标准 食品接触材料及制品 苯乙烯和乙苯的测定
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GB 31604.16-2016
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标准编号: GB 31604.16-2016 (GB31604.16-2016)
中文名称: 食品安全国家标准 食品接触材料及制品 苯乙烯和乙苯的测定
英文名称: Method for analysis of hygienic standard of unsaturated polyester resin and glass fibre reinforced plastics used as food containers and packaging materials
行业: 国家标准
中标分类: X09
字数估计: 8,866
发布日期: 2016-10-19
实施日期: 2017-04-19
旧标准 (被替代): GB/T 5009.98-2003部分; GB/T 5009.59-2003部分
标准依据: 国家卫生和计划生育委员会公告2016年第15号
GB 31604.16-2016: 食品安全国家标准 食品接触材料及制品 苯乙烯和乙苯的测定
GB 31604.16-2016 英文名称: Method for analysis of hygienic standard of unsaturated polyester resin and glass fibre reinforced plastics used as food containers and packaging materials
1 范围
本标准规定了食品接触材料及制品中苯乙烯和乙苯含量的气相色谱测定方法。
本标准适用于聚苯乙烯制品、不饱和聚酯树脂及其玻璃钢制品中苯乙烯和乙苯的测定。
2 原理
试样经二硫化碳提取后,进样气相色谱,在色谱柱中苯乙烯、乙苯与内标物正十二烷及其他组分分
离,用氢火焰离子化检测器检测,以内标法定量。
3 试剂和材料
3.1 试剂
二硫化碳(CS2,CAS号:75-15-0):色谱纯。
3.2 标准品
3.2.1 苯乙烯(C8H8,CAS号:100-42-5):纯度大于99.5%,或经国家认证并授予标准物质证书的标准
物质。
3.2.2 乙苯(C8H10,CAS号:100-41-4):纯度大于99.5%,或经国家认证并授予标准物质证书的标准
物质。
3.2.3 正十二烷(C12H26,CAS号:112-40-3):纯度大于99%,或经国家认证并授予标准物质证书的标
准物质。
3.3 标准溶液配制
3.3.1 苯乙烯标准储备液
称取200mg(精确至0.0001g)苯乙烯,用二硫化碳溶解后,定容至10mL,配制成浓度为
20mg/mL的储备液。溶液应于4℃避光密封储存,有效期为1周。
3.3.2 乙苯标准储备液
称取200mg(精确至0.0001g)乙苯,用二硫化碳溶解后,定容至10mL,配制成浓度为20mg/mL
的储备液。应于4℃避光密封储存,有效期为1周。
3.3.3 苯乙烯、乙苯混合中间液
用刻度吸量管分别吸取0.25mL的苯乙烯标准储备液及乙苯标准储备液至预先盛有5mL二硫化
碳的10mL容量瓶中,用二硫化碳稀释、定容,获得苯乙烯、乙苯混合中间液。其中苯乙烯及乙苯浓度
分别为500.0μg/mL、500.0μg/mL。溶液储存条件同3.3.1。
3.3.4 正十二烷内标储备液
称取250mg(精确至0.0001g)正十二烷,用二硫化碳溶解后,定容至10mL,配制成浓度为
25mg/mL的储备液。溶液储存条件同3.3.1。
3.3.5 正十二烷内标中间液
用刻度吸量管吸取0.50mL的正十二烷内标储备液至预先盛有5mL二硫化碳的10mL容量瓶
中,用二硫化碳定容,配制成浓度为1250μg/mL的中间液。溶液储存条件同3.3.1。
3.3.6 苯乙烯、苯乙烯及正十二烷混标工作液
用微量注射器及刻度吸量管分别移取50μL、250μL、500μL、1.0mL、2.5mL、5.0mL苯乙烯与乙
苯混合中间液于6个已加入5mL二硫化碳的25mL容量瓶中,再在每个容量瓶中加入1.0mL正已烷
内标中间液,用二硫化碳定容摇匀,获得工作溶液。苯乙烯及乙苯的浓度均分别为1.0μg/mL、
5.0μg/mL、10.0μg/mL、20.0μg/mL、50.0μg/mL、100.0μg/mL,内标浓度为50μg/mL。溶液储存条
件同3.3.1。
4 仪器和设备
4.1 气相色谱仪:配备氢火焰离子化检测器(FID)。
4.2 分析天平:感量0.0001g。
4.3 超声波清洗机。
4.4 冷冻研磨仪。
4.5 锥形瓶:25mL。
5 分析步骤
5.1 试样处理
可溶于二硫化碳的试样直接称量;不溶于二硫化碳的试样,先使用冷冻研磨仪或剪刀等切割工具将
其破碎成粒径小于1mm×1mm后再称量。切割样品时,不可使其发热变软。
5.2 试样溶液的制备
对于可溶于二硫化碳的试样,称取样品0.5g(精确到0.001g)试样于25mL容量瓶中,移取10mL
二硫化碳于容量瓶中,并加入1.0mL内标中间液。静置直至试样溶解后,用二硫化碳定容至刻度。对
于不溶于二硫化碳的试样,称取样品0.5g(精确到0.001g)试样于25mL锥形瓶中,移取10mL二硫化
碳于锥形瓶中。封盖后用超声波清洗机提取20min,取上层清液于25mL容量瓶中。然后,以同样方
法用10mL二硫化碳重复提取一次,合并两次上层清液于25mL容量瓶中,加入1.0mL内标中间溶液
并定容。若样品浓度超出线性范围,需重新提取,并在加入内标溶液前用二硫化碳适当稀释,使其浓度
处于线性范围内。不加试样,按照同样方法处理获得空白提取液。
5.3 空白溶液的制备
除不加试样外,采用与5.2完全相同的分析步骤、试剂和用量。
5.4 仪器参考条件
5.4.1 色谱柱:固定相为聚乙二醇,柱长30m、内径0.32mm、膜厚0.5μm。
5.4.2 进样口温度:250℃。
5.4.3 柱温:始温50℃下保持恒温1min,以10℃/min速率升温至140℃,再以20℃/min速率升温
至220℃,恒温10min。
5.4.4 进样方式:分流进样,分流比为2∶1。
5.4.5 载气:氮气,纯度大于99.999%,流量1.5mL/min。
5.4.6 检测器:氢火焰离子化检测器。
5.4.7 进样量:1μL。
5.4.8 检测器温度:300℃。
5.4.9 氢气流量:30mL/min,纯度≥99.999%。
5.4.10 空气流量:300mL/min,纯度≥99.999%。
5.5 标准曲线的制作
按照5.4所列条件,将苯乙烯、苯乙烯及正十二烷混标工作液进样气相色谱仪测定。以标准溶液工
作溶液中苯乙烯浓度(或乙苯浓度)为横坐标(单位为微克每毫升μg/mL),以对应苯乙烯峰面积(或乙
苯峰面积)与内标物正十二烷峰面积之比为纵坐标,分别绘制标准曲线。苯乙烯、乙苯及正十二烷标准
溶液的色谱图参见图A.1。
5.6 试样溶液的测定
按照5.4所列条件,将试样溶液、空白溶液进气相色谱仪测定,扣除空白值,得到苯乙烯(或乙苯)峰
6 分析结果的表述
试样中苯乙烯(或乙苯)含量按式(1)计算:
7 精密度
在重复性条件下获得的两次独立测定结果的绝对差值不得超过其算术平均值的10%。
8 其他
苯乙烯及乙苯方法检出限均为20mg/kg;苯乙烯及乙苯方法定量限均为50mg/kg。
GB 31604.16-2016
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National Food Safety Standard -
Food contact materials and articles -
determination of styrene and ethylbenzene
ISSUED ON. OCTOBER 19, 2016
IMPLEMENTED ON. APRIL 19, 2017
Issued by. National Health and Family Planning Commission of the PRC
3. No action is required - Full-copy of this standard will be automatically &
immediately delivered to your EMAIL address in 0~60 minutes.
Table of Contents
1 Scope .. 4
2 Principles ... 4
3 Reagents and materials .. 4
4 Instruments and equipment ... 6
5 Analytical procedures ... 6
6 Analysis results expression ... 8
7 Precision ... 8
8 Others ... 9
Appendix A Gas chromatogram of the standard solution ... 10
Foreword
This Standard replaces “Part 4.4 - Ethylbenzene compounds” of GB/T 5009.98-
2003 “Method for analysis of hygienic standard of unsaturated polyester resin
and glass fibre reinforced plastics used as food containers and packaging
materials”, “Part 6 - Styrene, ethylbenzene, and other volatile components” of
GB/T 5009.59-2003 “Method for analysis of hygienic standard of polystyrene
resin for food packaging”.
As compared with “Part 6 - Styrene, ethylbenzene, and other volatile
components” of GB/T 5009.59-2003, the main changes of this Standard are as
follows.
- CHANGE the Standard’s name to “National Food Safety Standard - Food
contact materials and articles - determination of styrene and ethylbenzene”;
- MODIFY the type of chromatographic column;
- ADD the method for determination of insoluble samples.
National Food Safety Standard -
Food contact materials and articles -
determination of styrene and ethylbenzene
1 Scope
This Standard specifies the gas chromatography method for determination of
styrene and ethylbenzene in food contact materials and articles.
This Standard applies to the determination of styrene and ethylbenzene in
polystyrene products, unsaturated polyester resin, and its glass fiber reinforced
plastic products.
2 Principles
After extracting the sample with carbon disulfide, INJECT the sample into gas
chromatography. Styrene, ethylbenzene, internal standard n-dodecane, and
other components are separated in the chromatographic column. USE
hydrogen flame ionization detector to detect; and USE internal standard method
to quantify.
3 Reagents and materials
3.1 Reagent
Carbon disulfide (CS2, CAS Number. 75-15-0). chromatographically pure.
3.2 Standards
3.2.1 Styrene (C8H8, CAS Number. 100-42-5). The purity shall be greater than
99.5%. Or the reference material certified by the state and awarded a Certificate
of Reference Material.
3.2.2 Ethylbenzene (C8H10, CAS Number. 100-41-4). The purity shall be greater
than 99.5%. Or the reference material certified by the state and awarded a
Certificate of Reference Material.
3.2.3 N-dodecane (C12H26, CAS Number. 112-40-3). The purity shall be greater
than 99%. Or the reference material certified by the state and awarded a
Certificate of Reference Material.
5 mL of carbon disulfide; then ADD 1.0 mL of internal standard intermediate
solution of n-hexane into each volumetric flask; USE carbon disulfide to dilute
them; and SHAKE well to obtain a working solution. The concentration of
styrene and ethylbenzene is 1.0 μg/mL, 5.0 μg/mL, 10.0 μg/mL, 20.0 μg/mL,
50.0 μg/mL, 100.0 μg/mL, respectively. The internal standard concentration is
50 μg/mL. The storage conditions of the solution are the same as those under
4 Instruments and equipment
4.1 Gas chromatograph. Equipped with hydrogen flame ionization detector
(FID).
4.2 Analytical balance. sensitivity is 0.0001 g.
4.3 Ultrasonic cleaning machine.
4.4 Cryogenic lapping instrument.
4.5 Conical flask. 25 mL.
5 Analytical procedures
5.1 Sample processing
samples that are insoluble in carbon disulfide shall be first crushed by cutting
tools such as a cryogenic lapping instrument or scissors, and then weighed
after being smaller than 1 mmX1 mm. When cutting a sample, do not heat or
soften it.
5.2 Preparation of sample solution
For samples that are soluble in carbon disulfide, WEIGH 0.5 g (accurate to
0.001 g) of the sample into a 25 mL volumetric flask; TRANSFER 10 mL of
carbon disulfide to the volumetric flask and ADD 1.0 mL of internal standard
intermediate solution. Let stand until the sample is dissolved, USE carbon
WEIGH 0.5 g (accurate to 0.001 g) of the sample into a 25 mL conical flask and
TRANSFER 10 mL of carbon disulfide to the conical flask. After capping, USE
an ultrasonic cleaning machine to extract for 20 min and TAKE the supernatant
into a 25 mL volumetric flask. Then, by the same method, USE 10 mL of carbon
disulfide to extract again; COMBINE the two supernatants in the 25 mL
volumetric flask; and ADD 1.0 mL of internal standard intermediate solution to
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