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食品安全国家标准 食品中铜的测定
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GB 5009.13-2017
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标准编号: GB 5009.13-2017 (GB5009.13-2017)
中文名称: 食品安全国家标准 食品中铜的测定
英文名称: National food safety standard -- Determination of copper in foods
行业: 国家标准
中标分类: X09
字数估计: 12,163
发布日期: 2017-04-06
实施日期: 2017-10-06
旧标准 (被替代): GB/T 23375-2009部分; GB/T 9695.22-2009; GB/T 14609-2008部分; GB/T 5009.13-2003; GB/T 18932.12-2002部分; GB 5413.21-2010部分; NY/T 1201-2006部分
标准依据: State Health and Family Planning Commission Notice No. 5 of 2017
GB 5009.13-2017: 食品安全国家标准 食品中铜的测定
GB 5009.13-2017 英文名称: National food safety standard -- Determination of copper in foods
1 范围
本标准规定了食品中铜含量测定的石墨炉和火焰原子吸收光谱法、电感耦合等离子体质谱法和电
感耦合等离子体发射光谱法。
本标准适用于各类食品中铜含量的测定。
第一法 石墨炉原子吸收光谱法
2 原理
试样消解处理后,经石墨炉原子化,在324.8nm处测定吸光度。在一定浓度范围内铜的吸光度值
与铜含量成正比,与标准系列比较定量。
3 试剂和材料
除非另有说明,本方法所用试剂均为优级纯,水为GB/T 6682规定的二级水。
3.1 试剂
3.1.1 硝酸(HNO3)。
3.1.2 高氯酸(HClO4)。
3.1.3 磷酸二氢铵(NH4H2PO4)。
3.1.4 硝酸钯[Pd(NO3)2]。
3.2 试剂配制
3.2.1 硝酸溶液(5+95):量取50mL硝酸,缓慢加入到950mL水中,混匀。
3.2.2 硝酸溶液(1+1):量取250mL硝酸,缓慢加入到250mL水中,混匀。
3.2.3 磷酸二氢铵-硝酸钯溶液:称取0.02g硝酸钯,加少量硝酸溶液(1+1)溶解后,再加入2g磷酸二
氢铵,溶解后用硝酸溶液(5+95)定容至100mL,混匀。
3.3 标准品
五水硫酸铜(CuSO4·5H2O,CAS号:7758-99-8):纯度 >99.99%,或经国家认证并授予标准物质
证书的一定浓度的铜标准溶液。
3.4 标准溶液配制
3.4.1 铜标准储备液(1000mg/L):准确称取3.9289g(精确至0.0001g)五水硫酸铜,用少量硝酸溶
液(1+1)溶解,移入1000mL容量瓶,加水至刻度,混匀。
3.4.2 铜标准中间液(1.00mg/L):准确吸取铜标准储备液(1000mg/L)1.00mL于1000mL容量瓶
中,加硝酸溶液(5+95)至刻度,混匀。
3.4.3 铜标准系列溶液:分别吸取铜标准中间液(1.00mg/L)0mL、0.500mL、1.00mL、2.00mL、
3.00mL和4.00mL于100mL容量瓶中,加硝酸溶液(5+95)至刻度,混匀。此铜标准系列溶液的质量
浓度分别为0μg/L、5.00μg/L、10.0μg/L、20.0μg/L、30.0μg/L和40.0μg/L。
注:可根据仪器的灵敏度及样品中铜的实际含量确定标准系列溶液中铜元素的质量浓度。
4 仪器和设备
注:所有玻璃器皿及聚四氟乙烯消解内罐均需硝酸(1+5)浸泡过夜,用自来水反复冲洗,最后用水冲洗干净。
4.1 原子吸收光谱仪:配石墨炉原子化器,附铜空心阴极灯。
4.2 分析天平:感量0.1mg和1mg。
4.3 可调式电热炉。
4.4 可调式电热板。
4.5 微波消解系统:配聚四氟乙烯消解内罐。
4.6 压力消解罐:配聚四氟乙烯消解内罐。
4.7 恒温干燥箱。
4.8 马弗炉。
5 分析步骤
5.1 试样制备
注:在采样和试样制备过程中,应避免试样污染。
5.1.1 粮食、豆类样品
样品去除杂物后,粉碎,储于塑料瓶中。
5.1.2 蔬菜、水果、鱼类、肉类等样品
样品用水洗净,晾干,取可食部分,制成匀浆,储于塑料瓶中。
5.1.3 饮料、酒、醋、酱油、食用植物油、液态乳等液体样品
将样品摇匀。
5.2 试样前处理
5.2.1 湿法消解
称取固体试样0.2g~3g(精确至0.001g)或准确移取液体试样0.500mL~5.00mL于带刻度消化
管中,加入10mL硝酸、0.5mL高氯酸,在可调式电热炉上消解(参考条件:120℃/0.5h~1h、升至
180℃/2h~4h、升至200℃~220℃)。若消化液呈棕褐色,再加少量硝酸,消解至冒白烟,消化液呈
无色透明或略带黄色,取出消化管,冷却后用水定容至10mL,混匀备用。同时做试剂空白试验。亦可
采用锥形瓶,于可调式电热板上,按上述操作方法进行湿法消解。
5.2.2 微波消解
称取固体试样0.2g~0.8g(精确至0.001g)或准确移取液体试样0.500mL~3.00mL于微波消解
罐中,加入5mL硝酸,按照微波消解的操作步骤消解试样,消解条件参考A.1。冷却后取出消解罐,在
电热板上于140℃~160℃赶酸至1mL左右。消解罐放冷后,将消化液转移至10mL容量瓶中,用少
量水洗涤消解罐2次~3次,合并洗涤液于容量瓶中,用水定容至刻度,混匀备用。同时做试剂空白
试验。
5.2.3 压力罐消解
称取固体试样0.2g~1g(精确至0.001g)或准确移取液体试样0.500mL~5.00mL于消解内罐
中,加入5mL硝酸。盖好内盖,旋紧不锈钢外套,放入恒温干燥箱,于140℃~160℃下保持4h~5h。
冷却后缓慢旋松外罐,取出消解内罐,放在可调式电热板上于140℃~160℃赶酸至1mL左右。冷却
后将消化液转移至10mL容量瓶中,用少量水洗涤内罐和内盖2次~3次,合并洗涤液于容量瓶中并用
水定容至刻度,混匀备用。同时做试剂空白试验。
5.2.4 干法灰化
称取固体试样0.5g~5g(精确至0.001g)或准确移取液体试样0.500mL~10.0mL于坩埚中,小
火加热,炭化至无烟,转移至马弗炉中,于550℃灰化3h~4h。冷却,取出,对于灰化不彻底的试样,加
数滴硝酸,小火加热,小心蒸干,再转入550℃马弗炉中,继续灰化1h~2h,至试样呈白灰状,冷却,取
出,用适量硝酸溶液(1+1)溶解并用水定容至10mL。同时做试剂空白试验。
5.3 测定
5.3.1 仪器参考条件
根据各自仪器性能调至最佳状态。参考条件见附录B。
按质量浓度由低到高的顺序分别将10μL铜标准系列溶液和5μL磷酸二氢铵-硝酸钯溶液(可根
据所使用的仪器确定最佳进样量)同时注入石墨炉,原子化后测其吸光度值,以质量浓度为横坐标,吸光
度值为纵坐标,制作标准曲线。
5.3.3 试样溶液的测定
与测定标准溶液相同的实验条件下,将10μL空白溶液或试样溶液与5μL磷酸二氢铵-硝酸钯溶
液(可根据所使用的仪器确定最佳进样量)同时注入石墨炉,注入石墨管,原子化后测其吸光度值,与标
准系列比较定量。
6 分析结果的表述
试样中铜的含量按式(1)计算。
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算术平均值的20%。
8 其他
当称样量为0.5g(或0.5mL),定容体积为10mL时,方法的检出限为0.02mg/kg(或0.02mg/L),定
量限为0.05mg/kg(或0.05mg/L)。
9 原理
试样消解处理后,经火焰原子化,在324.8nm处测定吸光度。在一定浓度范围内铜的吸光度值与
铜含量成正比,与标准系列比较定量。
10 试剂和材料
除非另有规定,本方法所用试剂均为优级纯,水为GB/T 6682规定的二级水。
10.1.1 硝酸(HNO3)。
10.1.2 高氯酸(HClO4)。
10.2 试剂配制
10.2.1 硝酸溶液(5+95):量取50mL硝酸,缓慢加入到950mL水中,混匀。
10.2.2 硝酸溶液(1+1):量取250mL硝酸,缓慢加入到250mL水中,混匀。
10.3 标准品
五水硫酸铜(CuSO4·5H2O,CAS号:7758-99-8):纯度 >99.99%,或经国家认证并授予标准物质
证书的一定浓度的铜标准溶液。
10.4 标准溶液配制
液(1+1)溶解,移入1000mL容量瓶,加水至刻度,混匀。
10.4.2 铜标准中间液(10.0mg/L):准确吸取铜标准储备液(1000mg/L)1.00mL于100mL容量瓶
中,加硝酸溶液(5+95)至刻度,混匀。
10.4.3 铜标准系列溶液:分别吸取铜标准中间液(10.0mg/L)0mL、1.00mL、2.00mL、4.00mL、
8.00mL和10.0mL于100mL容量瓶中,加硝酸溶液(5+95)至刻度,混匀。此铜标准系列溶液的质量
浓度分别为0mg/L、0.100mg/L、0.200mg/L、0.400mg/L、0.800mg/L和1.00mg/L。
注:可根据仪器的灵敏度及样品中铜的实际含量确定标准系列溶液中铜元素的质量浓度。
11 仪器设备
注:所有玻璃器皿及聚四氟乙烯消解内罐均需硝酸(1+5)浸泡过夜,用自来水反复冲洗,最后用水冲洗干净。
11.2 分析天平:感量0.1mg和1mg。
11.3 可调式电热炉。
11.4 可调式电热板。
11.5 微波消解系统:配聚四氟乙烯消解内罐。
11.6 压力消解罐:配聚四氟乙烯消解内罐。
11.7 恒温干燥箱。
11.8 马弗炉。
12 分析步骤
12.1 试样制备
12.2 试样前处理
同5.2。
12.3 测定
12.3.1 仪器测试条件
根据各自仪器性能调至最佳状态。参考条件见附录C。
12.3.2 标准曲线的制作
将铜标准系列溶液按质量浓度由低到高的顺序分别导入火焰原子化器,原子化后测其吸光度值,以
质量浓度为横坐标,吸光度值为纵坐标,制作标准曲线。
12.3.3 试样测定
其吸光度值,与标准系列比较定量。
GB 5009.13-2017
GB
NATIONAL STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
National food safety standard -
Determination of copper in foods
ISSUED ON. APRIL 06, 2017
IMPLEMENTED ON. OCTOBER 06, 2017
Issued by. National Health and Family Planning Commission of the PRC;
China Food and Drug Administration.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Principle... 4
3 Reagents and materials ... 4
4 Instruments and equipment ... 5
5 Analytical procedures ... 6
6 Presentation of analytical results ... 8
7 Precision... 9
8 Others ... 9
9 Principle... 9
10 Reagents and materials... 10
11 Instruments and equipment ... 11
12 Analytical procedures ... 11
13 Presentation of analytical results ... 12
14 Precision ... 13
15 Others ... 13
Appendix A Microwave digestion temperature rising program ... 14
Appendix B Instrument reference conditions of graphite furnace atomic
absorption spectrometry ... 15
Appendix C Flame atomic absorption spectrometry instrument reference
conditions ... 16
Foreword
This standard replaces GB/T 5009.13-2003 “Determination of copper in food”,
GB 5413.21-2010 “National food safety standard - Determination of calcium,
iron, zinc, sodium, potassium, magnesium, copper and manganese in foods for
infants and young children, milk and milk products”, GB/T 23375-2009
“Determination of copper, iron, zinc, calcium, magnesium and phosphorus
content in vegetables and derived products”, GB/T 9695.22-2009 “Meat and
meat products - Determination of copper content”, GB/T 14609-2008
“Inspection of grain and oils—Determination of copper, iron, manganese, zinc,
calcium, magnesium in cereals and derived products by atomic absorption and
flame spectrophotometry”, GB/T 18932.12-2002 “Method for the determination
of potassium, sodium, calcium, magnesium, zinc, iron, copper, manganese,
chromium, lead, cadmium contents in honey - Atomic absorption spectrometry”,
and NY/T 1201-2006 “Determination of copper iron and zinc content in
vegetables and derived products”.
As compared with GB/T 5009.13-2003, the main changes of this standard are
as follows.
- CHANGE the standard name into “National food safety standard -
Determination of copper in foods”;
- In the pretreatment method, ADD the wet digestion, pressure tank
digestion, and microwave digestion;
- RETAIN the graphite furnace atomic absorption spectrometry method as
the first method, using the ammonium dihydrogen phosphate-palladium
nitrate solution as a matrix modifier; RETAIN the flame atomic absorption
spectrometry method as the second method; and DELETE the
diethyldithiocarbamate colorimetric method
- ADD the inductively coupled plasma mass spectrometry method as the
third method;
- ADD the inductively coupled plasma emission spectrometry method as the
fourth method;
- ADD the microwave digestion temperature rising program, graphite
furnace atomic absorption spectrometry and flame atomic absorption
spectrometry instrument reference conditions as the appendixes.
National food safety standard -
Determination of copper in foods
1 Scope
This standard specifies the determination of copper content in food by graphite
furnace and flame atomic absorption spectrometry, inductively coupled plasma
spectrometry.
This standard applies to the determination of copper in all types of foods.
Method 1. Graphite furnace atomic absorption spectrometry
2 Principle
After digestion, the sample is atomized in graphite furnace AND the
absorbance is measured at 324.8 nm. In a certain concentration range, the
copper absorbance value is proportional to the copper content, AND it is
compared with the standard series for quantitative.
3 Reagents and materials
pure AND the water is the level II water as specified in GB/T 6682.
3.1 Reagents
3.1.1 Nitric acid (HNO3).
3.1.2 Perchloric acid (HClO4).
3.1.3 Ammonium dihydrogen phosphate (NH4H2PO4).
3.1.4 Palladium nitrate [Pd(NO3)2].
3.2 Reagent preparation
3.2.1 Nitric acid solution (5 + 95). MEASURE 50 mL of nitric acid; slowly ADD it
into 950 mL of water; MIX it uniformly.
into 250 mL of water; MIX it uniformly.
3.2.3 Ammonium dihydrogen phosphate-palladium nitrate solution. WEIGH
0.02 g of palladium nitrate; ADD a small amount of nitric acid solution (1 + 1) to
dissolve it; ADD 2 g of ammonium dihydrogen phosphate; after dissolving,
USE the nitric acid solution (5 + 95) to make its volume reach to 100 mL; MIX it
uniformly.
3.3 Standard substance
Copper sulfate pentahydrate (CuSO4 • 5H2O, CAS No.. 7758-99-8). purity >
99.99%, OR the copper standard solution of a certain concentration certified
3.4 Standard solution preparation
3.4.1 Standard copper stock solution (1000 mg/L). Accurately WEIGH 3.9289 g
(accurate to 0.0001 g) of copper sulfate pentahydrate; USE a small amount of
nitric acid (1 + 1) to dissolve it; TRANSFER t into a 1000 mL volumetric flask;
ADD water to the mark; MIX it uniformly.
3.4.2 Copper standard intermediate solution (1.00 mg/L). Accurately PIPETTE
1.00 mL of copper standard stock solution (1000 mg/L) into a 1000 mL
volumetric flask; ADD nitric acid solution (5 + 95) to the mark; MIX it uniformly.
3.4.3 Copper standard series solution. respectively PIPETTE 0 mL, 0.500 mL,
solution (1.00 mg/L) into a 100 mL volumetric flask; ADD nitric acid solution (5
+ 95) to the mark; MIX it uniformly. The concentration of this copper standard
series solution is 0 μg/L, 5.00 μg/L, 10.0 μg/L, 20.0 μg/L, 30.0 μg/L and 40.0
μg/L, respectively.
Note. It may be based on the sensitivity of the instrument and the actual
content of copper in the sample to determine the mass concentration of the
copper element in the standard series solution.
4 Instruments and equipment
Note. All glassware and Teflon digestion inner tanks must be soaked in nitric
with water.
4.1 Atomic absorption spectrometer. with graphite furnace atomizer and
copper hollow cathode lamp.
4.2 Analytical balance. sensitivity of 0.1 mg and 1 mg.
4.3 Adjustable electric furnace.
4.4 Adjustable heating plate.
4.5 Microwave digestion system. with polytetrafluoroethylene digestion inner
tank.
4.6 Pressure digestion tank. with polytetrafluoroethylene digestion inner tank.
4.8 Muffle furnace.
5 Analytical procedures
5.1 Sample preparation
Note. Sample contamination shall be avoided during sampling and sample
preparation.
5.1.1 Food and beans samples
After removing of debris, the sample is crushed and stored in a plastic bottle.
5.1.2 Vegetables, fruits, fish, meat and other samples
The sample is washed with water and dried naturally, AND the edible part is
5.1.3 Drinks, wine, vinegar, soy sauce, edible vegetable oil, liquid milk
and other liquid samples
SHAKE the sample uniformly.
5.2 Sample preparation
5.2.1 Wet digestion
WEIGH 0.2 g ~ 3 g (accurate to 0.001 g) of solid sample or accurately
PIPETTE 0.500 mL ~ 5.00 mL of liquid sample into in the graduated digestion
tube; ADD 10 mL of nitric acid and 0.5 mL of perchloric acid; MAKE it digested
on the adjustable electric furnace (reference conditions. 120 °C / 0.5 h ~ 1 h;
220 °C). If the digestion solution is in tan, ADD a small amount of nitric acid to
digest it until white smoke is produced and the digestion solution is in colorless
transparent or slightly yellow; TAKE the digestion tube out; COOL it down, USE
water to make its volume reach to 10 mL; MIX it uniformly to prepare for use.
Meanwhile MAKE the reagent blank test. It may also use the conical flask; and
PERFORM wet digestion on the adjustable heating plate in accordance with
the aforementioned operation procedures.
5.2.2 Microwave digestion...
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