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食品安全国家标准 食品中多种磷酸盐的测定
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GB 5009.256-2016
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标准编号: GB 5009.256-2016 (GB5009.256-2016)
中文名称: 食品安全国家标准 食品中多种磷酸盐的测定
英文名称: National Standard of Food Safety -- Determination of Phosphates in Foods
行业: 国家标准
中标分类: X09
字数估计: 8,836
发布日期: 2016-08-31
实施日期: 2017-03-01
标准依据: 国家卫生和计划生育委员会公告2016年第11号
GB 5009.256-2016: 食品安全国家标准 食品中多种磷酸盐的测定
GB 5009.256-2016 英文名称: National Standard of Food Safety -- Determination of Phosphates in Foods
中华人民共和国国家标准
1 范围
本标准规定了食品中多种磷酸盐的测定方法。
本标准适用于食品中磷酸盐、焦磷酸盐、六偏磷酸盐、三偏磷酸盐、三聚磷酸盐的测定。
5 分析步骤
5.1 试样制备
5.1.1 鱼、肉类及其制品:取500g鱼、肉或其制品的可食部分,捣碎混匀。冷冻保存。
5.1.2 蔬菜、水果:取可食部分500g,洗净、晾干、切碎、混匀,用组织搅拌机制成匀浆备用。
5.1.3 奶粉、乳制品饮料或饮料类:通过反复摇晃和颠倒容器使样品充分混匀直到使样品均一化。
5.1.4 固体油脂、脂肪等样品:取500g的样品研磨成均匀的泥浆状。为避免水分损失,研磨过程中应避免产生过多的热量。
5.1.5 杂粮、小麦粉及其制品、果冻、巧克力、糖果、膨化食品、熟制坚果与籽类:取500g可食部分用食物粉碎机搅匀备用。
5.1.6 调味料:粉末状调味料通过反复摇晃和颠倒容器使样品充分混匀;固体大颗粒状调味料取500g
用食物粉碎机搅匀备用。
5.1.7 谷类和淀粉类甜品、米粉、婴幼儿配方食品及辅助食品:通过反复摇晃和颠倒容器使样品充分混匀直到使样品均一化。
注:在试样制备过程中,应防止样品受到污染。
5.2 样品前处理
5.2.1 样品的提取
5.2.1.1 蔬菜、水果、果冻、巧克力及糖果、杂粮、小麦粉及其制品、奶粉、乳制品饮料或饮料类:称取
2.5g(精确至0.001g,可适当调整试样的取样量)试样,用50mmol/L氢氧化钠溶液洗入50mL比色管
中混匀定容至刻度,80℃超声提取30min,每隔5min振摇一次,保持固定相完全分散。冷却至室温
后,溶液经滤纸过滤;取滤液于4℃下,8000r/min离心10min,取上清液备用。
5.2.1.2 膨化食品、熟制坚果与籽类、谷类和淀粉类甜品、米粉、婴幼儿配方食品及辅助食品:称取2.5g
(精确至0.001g,可适当调整试样的取样量)试样,用50mmol/L氢氧化钠溶液洗入25mL比色管中混
匀定容至刻度,80℃超声提取30min,每隔5min振摇一次,保持固定相完全分散。冷却至室温后,溶
液经滤纸过滤;取滤液于4℃下,8000r/min离心10min,取上清液备用。
5.2.1.3 油脂、脂肪、调味料:称取1g(精确至0.001g,可适当调整试样的取样量)试样,用50mmol/L
氢氧化钠溶液洗入50mL比色管中混匀定容至刻度,80℃超声提取30min,每隔5min振摇一次,保持
固定相完全分散。冷却至室温后,溶液经滤纸过滤;取滤液于4℃下,8000r/min离心10min,取水相清液备用。
5.2.1.4 鱼、肉类及其制品:称取2.5g(精确至0.001g,可适当调整试样的取样量)试样,用50mmol/L
氢氧化钠溶液洗入100mL比色管中混匀定容至刻度,80℃超声提取30min,每隔5min振摇一次,保
持固定相完全分散。冷却至室温后,溶液经滤纸过滤;取滤液于4℃下,8000r/min离心10min,取上清液备用。
5.2.2 样品的净化
取5.2.1中处理完成后的上清液约15mL,通过0.45μm水性滤膜针头过滤器、OnGuardⅡRP,弃
去前面3mL(如果氯离子大于100mg/L,则需要依次通过针头过滤器、OnGuardⅡ RP、Ag柱和
Na柱,弃去前7mL),收集后面洗脱液待测。测定前应根据样品含量对待测液进行适当稀释。
固相萃取柱使用前需进行活化,如使用OnGuardⅡ RP柱(1.0mL)、OnGuardⅡ Ag柱(1.0mL)
和OnGuardⅡ Na柱(1.0mL),其活化过程为:OnGuardⅡ RP柱(1.0mL)使用前依次用10mL甲
醇、15mL水通过,静置活化30min。OnGuardⅡ Ag柱(1.0mL)和 OnGuardⅡ Na柱(1.0mL)用10mL水通过,静置活化30min。
5.3 参考色谱条件
5.3.1 色谱柱:氢氧化物选择性,可兼容梯度洗脱的高容量阴离子交换柱,如DionexIonpacAS11-HC
4mm×250mm(带IonpacAG11-HC型保护柱4mm×50mm),或性能相当的离子色谱柱。
5.3.2 淋洗液:氢氧化钾溶液,梯度淋洗时间及氢氧化钾浓度见表2;流速1.0mL/min。
5.3.3 抑制器:连续自动再生膜阴离子抑制器或等效抑制装置。
5.3.4 检测器:电导检测器。
5.3.5 柱温箱:柱温箱温度为30℃。
5.3.6 进样体积:100μL(可根据试样中被测离子含量进行调整)。
5.4 标准曲线的制作
将标准系列工作液从低浓度到高浓度依次进样,测定相应的电导检测器的信号值,得到各浓度标准
溶液的色谱图。以标准工作液的浓度(mg/L)为横坐标,以峰面积(μs)或峰高为纵坐标,绘制标准曲线,
并计算线性回归方程。参考色谱图及保留时间见附录B。
5.5 试样溶液的测定
将试样溶液在相同工作条件下注入离子色谱仪中,记录色谱图,以保留时间定性,测定样品的峰面
积(μs)或峰高,根据标准曲线得到待测液中被测组份的浓度。
5.6 空白试验空白试验系指除不加试样外,采用完全相同的分析步骤、试剂和用量,进行平行操作。
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算术平均值的15%。
8 其他
本标准的检出限和定量限如下:
a) 膨化食品、熟制坚果与籽类谷类和淀粉类甜品、米粉、婴幼儿配方食品及辅助食品:取样2.5g,
定容50mL,测定前再稀释2.5倍,测定各多聚磷酸根的检出限分别为正磷酸根1.5mg/kg,焦
磷酸根1.4mg/kg,三聚磷酸根1.5mg/kg,三偏磷酸根1.6mg/kg,六偏磷酸根4.8mg/kg,定
量限分别为正磷酸根5.0mg/kg,焦磷酸根5.0mg/kg,三聚磷酸根5.0mg/kg,三偏磷酸根5.0mg/kg,六偏磷酸根15mg/kg。
b) 蔬菜、水果、果冻、巧克力及糖果、杂粮、小麦粉及其制品、奶粉、乳制品饮料或饮料类:取样
2.5g,定容50mL,测定前再稀释5倍,测定各多聚磷酸根的检出限分别为正磷酸根3.0mg/kg,
焦磷酸根2.8mg/kg,三聚磷酸根3.0mg/kg,三偏磷酸根3.2mg/kg,六偏磷酸根9.6mg/kg,
定量限分别为正磷酸根10mg/kg,焦磷酸根10mg/kg,三聚磷酸根10mg/kg,三偏磷酸根10mg/kg,六偏磷酸根30mg/kg。
c) 油脂、脂肪、调味料:取样1.0g,定容50mL,鱼、肉类 取样2.5g,定容100mL,测定前再稀释
2.5倍,测定各多聚磷酸根的检出限分别为正磷酸根6.0mg/kg,焦磷酸根5.6mg/kg,三聚磷
酸根6.0mg/kg,三偏磷酸根6.4mg/kg,六偏磷酸根19.2mg/kg,定量限分别为正磷酸根
20mg/kg,焦磷酸根20mg/kg,三聚磷酸根20mg/kg,三偏磷酸根20mg/kg,六偏磷酸根60mg/kg。
附 录 A
聚磷酸根的换算系数
聚磷酸根换算为正磷酸根的换算系数见表A.1。
GB 5009.256-2016
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National Standard of Food Safety -
Determination of Phosphates in Foods
ISSUED ON. AUGUST 31, 2016
IMPLEMENTED ON. MARCH 01, 2017
Issued by. National Health and Family Planning Commission of PRC
Table of Contents
1 Scope ... 3
2 Principle ... 3
3 Reagents and Materials ... 3
4 Apparatus ... 5
5 Analytical Procedures ... 5
6 Expression of Analytical Results ... 9
7 Precision ... 9
8 Others ... 9
Appendix A Conversion Factor of Polyphosphate Radical ... 11
Appendix B Five Different Phosphate Radical Standard Ion Chromatograms 12
National Standard of Food Safety -
Determination of Phosphates in Foods
1 Scope
This Standard specifies the determination of phosphates in foods.
This Standard is applicable to the determination of phosphate, pyrophosphate,
hexametaphosphate, trimetaphosphate, and tripolyphosphate in foods.
2 Principle
The specimen sampling shall adopt the corresponding method to extract and purify;
take the potassium hydroxide solution as the eluent; separated by anion exchange
column and detected by conductivity detector. Qualitative with retention time, and
quantified by external standard method.
3 Reagents and Materials
Unless otherwise stated, the reagents used in this method are all guarantee reagents;
while water is Level-I water as specified in GB/T 6682.
3.1 Reagents
3.1.1 Sodium hydroxide (NaOH).
3.1.2 Potassium hydroxide (KOH).
3.1.3 Methanol (CH3OH) chromatographically pure.
3.2 Reagent preparation
3.2.1 Sodium hydroxide (10mmol/L). take 0.4g of sodium hydroxide; dissolve into
water; dilute and make constant volume of 1000mL.
3.2.2 Sodium hydroxide (50mmol/L). take 2.0g of sodium hydroxide; dissolve into
water; dilute and make constant volume of 1000mL.
3.3 Standard substance
5.2.1.3 Oil, fat, sauces. take 1g (accurate to 0.001g, the sampling quantity of the
specimen can be adjusted properly) of specimen; use 50mmol/L sodium hydroxide
solution to wash into 50mL colorimetric tube; mix evenly and make constant volume to
the scale; perform ultrasonic extraction at 80°C for 30min; shake once every 5min;
keep the stationary phase completely dispersed. After cooling to the room temperature,
the solution was filtered through filter paper; take filtrate at 4°C, centrifuge at 8000r/min
for 10min; take the supernatant for later-use.
5.2.1.4 Fish, meat and its products. take 2.5g (accurate to 0.001g, the sampling
quantity of the specimen can be adjusted properly) of specimen; use 50mmol/L sodium
hydroxide solution to wash into 100mL colorimetric tube; mix evenly and make
constant volume to the scale; perform ultrasonic extraction at 80°C for 30min; shake
once every 5min; keep the stationary phase completely dispersed. After cooling to the
room temperature, the solution was filtered through filter paper; take filtrate at 4°C,
centrifuge at 8000r/min for 10min; take the supernatant for later-use.
5.2.2 Sample purification
Take approximately 15mL of supernatant after treatment in 5.2.1; pass through a
0.45µm aqueous membrane needle filter; OnGuard II RP; discharge the first 3mL (if
the chloride ion is greater than 100mg/L, then successively pass through needle filter,
OnGuard II RP, Ag column and Na column, discharge the first 7mL); collect the back
eluent to be tested. Appropriately dilute the to-be-tested solution as per the sample
content before measurement.
The solid phase extraction column needs to be activated before use; e.g. when using
OnGuard II RP column (1.0mL), OnGuard II Ag column (1.0mL) and OnGuard II Na
column (1.0mL), their activation processes are as follows. before use, the OnGuard II
RP column (1.0mL) shall successively be passed through by 10mL of methanol and
15mL of water; stand and activate for 30min. For OnGuard II Ag column (1.0mL) and
and activate for 30min.
5.3 Reference chromatographic conditions
5.3.1 Chromatographic column. the selection of hydroxide can be compatible with
the gradient elution high volume anion exchange column, such as Dionex lonpac AS11-
HC 4mm×250mm (with Ionpac AG11-HC type guard column 4mm×50mm), or ion
chromatographic column with equivalent functions.
5.3.2 Eluent. potassium hydroxide solution; the gradient elution time and potassium
hydroxide concentration can refer to Table 2, flow rate of 1.0mL/min.
for trimetaphosphate radical, 4.8mg/kg for hexametaphosphate radical, respectively;
for pyrophosphate radical, 5.0mg/kg for tripolyphosphate radical, 5.0mg/kg for
trimetaphosphate radical, 15mg/kg for hexametaphosphate radical, respectively.
b) Vegetables, fruits, jellies, chocolate and candies, miscellaneous grains, wheat flour
and products, milk powder, dairy beverages or beverages. take 2.5g of sample; make
constant volume of 50mL; dilute 5 times before test; the detection limits for various
polyphosphate radicals are tested as follows. 3.0mg/kg for phosphate radical,
2.8mg/kg for pyrophosphate radical, 3.0mg/kg for tripolyphosphate radical, 3.2mg/kg
for trimetaphosphate radical, 9.6mg/kg for hexametaphosphate radical, respectively;
while their quantitative limits are as follows. 10mg/kg for phosphate radical, 10mg/kg
trimetaphosphate radical, 30mg/kg for hexametaphosphate radical, respectively.
c) Oils, fats, sauces. take 1.0g of sample; make constant volume of 50mL; take 2.5g
of fish and meat samples; make constant volume of 100mL; dilute 2.5 times before
test; the detection limits for various polyphosphate radicals are tested as follows.
6.0mg/kg for phosphate radical, 5.6mg/kg for pyrophosphate radical, 6.0mg/kg for
tripolyphosphate radical, 6.4mg/kg for trimetaphosphate radical, 19.2mg/kg for
hexametaphosphate radical, respectively; while their quantitative limits are as follows.
20mg/kg for phosphate radical, 20mg/kg for pyrophosphate radical, 20mg/kg for
tripolyphosphate radical, 20mg/kg for trimetaphosphate radical, 60mg/kg for
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