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GB/T 5009.94-2003Determination of rare earth elements in plant food (English PDF)

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Issued by

Ministry of Health of the People's Republic of China

Level / Type

National · Recommended

Issue date

January 1, 1970

Implementation date

January 1, 1970

Scope

GB/T 5009.94-2003 (Determination of rare earth elements in plant food) is available as an English-translated PDF.

GB/T 5009.94-2003 — This Chinese standard specifies the inductively coupled plasma mass spectrometry method of rare earth elements in plant foods.

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Document preview — GB/T 5009.94-2003

National Standard of the People's Republic of China

ICS: 67.040
Classification: C 53
Replacing: GB/T 5009.94-2003; GB/T 7630-1987; GB/T 22290-2008; GB/T 23199-2008

Issued by: Ministry of Health of the People's Republic of China

Foreword
3 Reagents and materials
3.1 Reagents
3.2 Reagent preparation
3.3 Standard
3.4 Standard Solution
4 Instruments and equipment
5 Step, Analysis
5.1 Sample Preparation
5.2 Sample Digestion
5.3 Instrument Reference conditions
7 Precision
8 Other

Foreword

This standard replaces GB/T 5009.94-2003 "Determination of rare earths in vegetable foods" and at the same time instead of GB/T 22290-2008 "tea Leaves of rare earth elements by inductively coupled plasma mass spectrometry ", GB/T 23199-2008" tea rare earth elements by inductively coupled Combined plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry, "rare earth oxide wheat GB/T 7630-1987 1 Scope this standard specifies the method of rare earth elements in plant foods measured by inductively coupled plasma mass spectrometry.

This standard applies to grain cereals, legumes, vegetables, fruits, tea and other plant foods scandium (Sc), yttrium (Y), lanthanum (La), Cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), Erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu) measurement.

Principle 2

The sample was treated as sample digestion solution, the sample solution is atomized by a carrier gas is fed into the plasma torch or ICP, after evaporation, Dissociation and ionization of atoms and other processes, converted to positively charged ions, the ion-collection system into the mass spectrometer, the mass spectrometer according to their mass charge Separation ratio. For the mass-to-charge ratio, the signal intensity is proportional to the mass number of the ions into the mass spectrometer, i.e., the concentration of the sample mass and the letter Number proportional to the intensity. Element concentration was determined by measuring the mass of the sample solution in the signal strength.

3 Reagents and materials

3.1 Reagents

Note. Unless otherwise indicated, the reagents used in this method are excellent pure water as a water GB/T 6682 regulations.

3.1.1 nitric acid (HNO3).

3.1.2 argon (Ar). purity argon gas ( > 99.999%) or liquid argon.

3.2 Reagent preparation

Nitric acid solution (5 + 95). 50 mL of nitric acid, dilute with water to 1000 mL.

3.3 Standard

3.3.1 REE stock solution (10 µg/mL) (Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu).

3.3.2 the internal standard stock solution (10 µg/mL) (Rh, In, Re).

3.3.3 instrument tuning stock solution (10 ng/mL) (Li, Co, Ba, Tl).

3.4 Standard Solution

3.4.1 The use of rare earth elements mixed standard solution (100 ng/mL). Take the right amount of Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, the elements Ho, Er, Tm, Yb, Lu single standard or standard stock solution element mixed standard stock solution with a nitric acid solution by Grade diluted to a concentration of 100.0 µg/L using the element mixed standard solution.

3.4.2 standard curve working solution. Apply the solution using standard elements mixed with nitric acid solution formulated at a concentration of 0 µg/L, 0.0500 µg/L, 0.100 µg/L, 0.500 µg/L, 1.00 µg/L, 2.00 µg/L standard series or concentration of 0 µg/L, 1.00 µg/L, 2.00 µg/L, 5.00 µg/L, 10.0 µg/L, 20.0 µg/L standard series, also based on the concentration of rare earth elements in the sample solution appropriate standards regulating the concentration series Range.

3.4.3 an internal standard solution (1 µg/mL). proper amount of internal standard stock solution (10 µg/mL), diluted 10-fold with a solution of nitric acid (595), the concentration of of 1 µg/mL.

3.4.4 instrument tuning use solution (1 ng/mL). instrument tuning take appropriate stock solution was diluted with a solution of nitric acid (595) 10-fold concentration of 1 ng/mL.

4 Instruments and equipment

4.1 Inductively coupled plasma mass spectrometry (ICP-MS).

4.2 Balance. a sense of the amount of 0.1 mg and 1 mg.

4.3 high-pressure sealed microwave digestion system with high pressure teflon digestion tank.

4.4 closed high pressure digestion device with digestion inner tank.

4.5 thermostatic oven (oven).

4.6 50 °C ~ 200 °C temperature heating plate.

5 Step, Analysis

5.1 Sample Preparation

5.1.1 Sample pretreatment

5.1.1.1 dry sample. grain cereals, beans and other edible parts taken by high speed grinding mill, mix and set aside.

5.1.1.2 wet sample. vegetables, fruits and other edible parts taken, washed clean, dry gauze or wipe dry, homogenized by homogenizer, spare.

5.2 Sample Digestion

5.2.1 Microwave Digestion. Weigh 0.2 g ~ 0.5 g (accurate to 0.001 g) at high pressure digestion tank, added 5 mL HNO3, tighten the lid, Place 1 h, according to the microwave digestion instrument's standard operating procedures digestion (digestion conditions see Table A.1). Removed after cooling, slowly open the Lid exhaust, high pressure digestion tank placed on a hot plate temperature, rush acid at 140 °C. Remove and let cool digestion tank, digestive juices will be transferred to 10 mL ~ 25 mL flask with a small amount of water 3 washes tank washings were combined in the flask and dilute to volume, mix standby; while for trial Agent blank.

5.2.2 closed high pressure tank Solution. Weigh sample 0.5 g ~ 1.g (accurate to 0.001 g) in digestion in the tank, added 5 mL of nitric acid immersion overnight. Inside cover cap, tighten stainless steel jacket, put in oven temperature, 140 °C ~ 160 °C holding 4 h ~ 6 h, the natural cooling box to room temperature, slowly unscrew the stainless steel jacket, inside the digestion tank removed and placed on a hot plate temperature, rush acid at 140 °C. Digestion inner tank discharge After cooling, the digest was transferred to a 10 mL ~ 25 mL volumetric flask, with a small amount of water 3 washes tank washings were combined in the flask and is scheduled to volume, mix standby; at the same time as a reagent blank.

5.3 Instrument Reference conditions

5.3.1 The device according to standard operating procedures for commissioning the instrument start, quality calibration, argon gas flow rate and the like. Suitable conditions for selection, including Nebulizer flow rate detector and the ion lens voltage, RF incident power, so that the formation of oxides CeO/Ce 6 expression analysis I-th sample REE contents in accordance with the formula (1).

Where.

- I-th sample rare earth element content in milligrams per kilogram (mg/kg);

- I-th sample solution measured values of rare earth elements, in micrograms per liter (µg/L);

- Sample blank solution in the i-th measured value of rare earth elements, in micrograms per liter (µg/L);

V-- the sample digest volume to volume, in milliliters (mL of);

m-- sample weight in grams (g);

1000-- unit conversion.

The arithmetic mean of the results obtained with the two under the same condition of independent measurement results expressed reservations three significant figures.

If the oxide content analysis results need to be expressed, then see Appendix B, the content of each element multiplied by a conversion factor F.

7 Precision

When samples of scandium, yttrium, lanthanum, cerium, neodymium and other rare earth element content of greater than 10 µg/kg, twice under repeated conditions of independence when the absolute difference between the measurement results shall not exceed 10% of the arithmetic mean of the sample the rare earth element content of less than 10 µg/kg, in the same condition Two independent determination results obtained under the absolute difference may not exceed 20% of the arithmetic mean.

8 Other

The detection limit of this standard. sample 0.5 g, volume 10 mL, measured each rare earth element detection limits (µg/kg) were Sc 0.6, Y 0.3, La 0.4, Ce 0.3, Pr 0.2, Nd 0.2, Sm 0.2, Eu 0.06, Gd 0.1, Tb 0.06, Dy 0.08, Ho 0.03, Er 0.06, Tm 0.03, Yb 0.06, Lu 0.03. The limit of quantitation (µg/kg) were Sc 2.1, Y 1.1, La 1.4, Ce 0.9, Pr 0.7, Nd 0.8, Sm 0.5, Eu 0.2, Gd 0.5, Tb 0.2, Dy 0.3, Ho 0.1, Er 0.2, Tm 0.1, Yb 0.2, Lu 0.1.

Appendix A

Sample measurement reference conditions A.1 microwave digestion reference conditions shown in Table A.1.

Table A.1 microwave digestion Reference conditions

The step of controlling the temperature Heating time min Holding time min A.2 inductively coupled plasma mass spectrometer operating conditions refer to Table A.2.

Table A.2 inductively coupled plasma mass spectrometer operating conditions refer

Instrument Instrument Parameter Value Parameter Value RF power 1350 W Nebulizer salt type Plasma gas flow rate 15 L/min Acquisition mode Spectrum Auxiliary gas flow 1.0 L/min measured 3 points the carrier gas flow rate 1.14 L/min Automatic Detection Spray chamber temperature 2 °C 3 repetitions Appendix B the rare earth element oxide conversion factor Oxides of rare earth elements and common, each element in terms of oxide conversion factor, see Table B.1.

Table B.1 common oxides of rare earth elements and each element is converted to oxide conversion factor

A element atomic weight molecular weight M m M oxide AmOn conversion factor F Sc 44.96 Sc2O3 137.9 2 1.534 Y 88.91 Y2O3 225.8 2 1.270 La 138.9 La2O3 325.8 2 1.173 Ce 140.1 CeO2 172.1 1 1.228 Pr 140.9 Pr6O11 1021.4 6 1.208 Nd 144.2 Nd2O3 336.4 2 1.166 Sm 150.4 Sm2O3 348.8 2 1.160 Eu 152.0 Eu2O3 352.0 2 1.158 Gd 157.3 Gd2O3 362.6 2 1.153 Tb 158.9 Tb4O7 747.6 4 1.176 Dy 162.5 Dy2O3 373.0 2 1.148 Ho 164.9 Ho2O3 377.8 2 1.146 Er 167.3 Er2O3 382.6 2 1.143 Tm 168.9 Tm2O3 385.8 2 1.142 Yb 173.0 Yb2O3 394.0 2 1.139 Lu 175.0 Lu2O3 398.0 2 1.137 Note. Each element in terms of oxide conversion factor F F = M [AmOn]/(m · M [A]) where.

A-- rare earth elements;

M [A] - atomic weight rare earth elements;

M [AmOn] - rare earth oxide molecular weight;

m-- rare earth oxides of rare earth elements in the formula-based mole.

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This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 7 pages — is available in the English PDF.

Referenced standards

Cited by

GB/T 22111-2008Product of geographical indication - Puer tea

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