GB/T 13079-2022 English PDF (GBT13079-2022)

Delivery: 3 seconds. Download true-PDF + Invoice.
Get QUOTATION in 1-minute: Click GB/T 13079-2022
Historical versions: GB/T 13079-2022
Preview True-PDF (Reload/Scroll if blank)

GB/T 13079-2022: Determination of total arsenic in feeds
GB/T 13079-2022
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 65.120
CCS B 46
Replacing GB/T 13079-2006
Determination of Total Arsenic in Feeds
ISSUED ON: DECEMBER 30, 2022
IMPLEMENTED ON: JULY 1, 2023
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative References ... 5
3 Terms and Definitions ... 5
4 Silver Salt Method (arbitration method) ... 5
5 Hydride Generation-atomic Fluorescence Spectrometry ... 12
6 Inductively Coupled Plasma Mass Spectrometry ... 18
Appendix A (informative) Microwave Digestion Reference Conditions ... 23
Determination of Total Arsenic in Feeds
1 Scope
This document describes the silver salt method, hydride generation-atomic fluorescence
spectrometry and inductively coupled plasma mass spectrometry for the determination of total
arsenic in feeds.
This document is applicable to the determination of total arsenic in compound feeds,
concentrated feeds, concentrate supplements, additive premixed feeds, feedstuffs and feed
additives.
When the sampling size is 5 g and the constant volume is 50 mL, the detection limit of the silver
salt method is 0.25 mg/kg and the quantitation limit is 0.50 mg/kg; when the sampling size is 5
g, the constant volume is 50 mL and the dilution factor is 20, the detection limit of the hydride
generation-atomic fluorescence spectrometry and inductively coupled plasma mass
spectrometry is 0.02 mg/kg, and the quantitation limit is 0.05 mg/kg.
2 Normative References
The contents of the following documents constitute indispensable clauses of this document
through the normative references in the text. In terms of references with a specified date, only
versions with a specified date are applicable to this document. In terms of references without a
specified date, the latest version (including all the modifications) is applicable to this document.
GB/T 6682 Water for Analytical Laboratory Use - Specification and Test Methods
GB/T 20195 Animal Feed - Preparation of Test Samples
3 Terms and Definitions
This document does not have terms or definitions that need to be defined.
4 Silver Salt Method (arbitration method)
4.1 Principle
After a specimen is treated by acid digestion, direct acid dissolution or dry ashing method, use
potassium iodide and stannous chloride to reduce high-valent arsenic to trivalent arsenic, then,
generate arsine with the new ecological hydrogen produced by zinc particles and acid, which is
absorbed by the silver diethyldithiocarbamate (Ag-DDTC)-triethylamine-chloroform solution
to form a red jelly, whose color shade is proportional to the arsenic content. Use a
spectrophotometer to determine the absorbance and quantitatively compare it with standard
series of solutions.
4.2 Reagents or Materials
WARNING---handle all kinds of strong acids with caution. Dilute and use them in a fume
hood. When using perchloric acid, be careful not to burn it to dryness, and be careful of
explosion.
Unless otherwise specified, use only analytically pure reagents.
4.2.1 Water: GB/T 6682, Grade-2.
4.2.2 Nitric acid.
4.2.3 Hydrochloric acid.
4.2.4 Chloroform.
4.2.5 Magnesium oxide.
4.2.6 Magnesium nitrate.
4.2.7 L-ascorbic acid.
4.2.8 Arsenic-free zinc particles: with a particle size of 3.0 mm  0.2 mm.
4.2.9 Mixed acid solution: nitric acid + perchloric acid + sulfuric acid = 230 + 50 + 30. Mix it
well and store it in a brown reagent bottle.
4.2.10 Hydrochloric acid solution (6 mol/L): measure-take 250 mL of hydrochloric acid (4.2.3),
add 250 mL of water and mix it well.
4.2.11 Magnesium nitrate solution: weigh-take 180 g of magnesium nitrate [Mg (NO3)2  6H2O],
add water to dissolve it, dilute and reach a constant volume of 1,000 mL, and mix it well.
4.2.12 Potassium iodide solution (150 g/L): weigh-take 75 g of potassium iodide, add water to
dissolve it, dilute to 500 mL, mix it well, and store in a brown bottle.
4.2.13 Acidic stannous chloride solution: weigh-take 40 g of stannous chloride (SnCl2  2H2O),
use 100 mL of hydrochloric acid (4.2.3) to dissolve it, then, add a few tin particles, and store in
a brown reagent bottle. The shelf life is 1 week.
4.2.14 Silver diethyldithiocarbamate (Ag-DDTC)-triethylamine-chloroform solution (2.5 g/L):
weigh-take 2.5 g (accurate to 0.0001 g) of Ag-DDTC in a dry beaker, add an appropriate amount
of chloroform. After it is completely dissolved, add 20 mL of triethylamine, use chloroform to
transfer it to a 1,000 mL volumetric flask, reach a constant volume and mix it well; store it in a
brown reagent bottle and in the dark at 2 C ~ 8 C. If there is precipitation, it shall be filtered
before use.
4.2.15 Lead acetate solution (200 g/L): weigh-take 40 g of lead acetate, add water to dissolve
it, dilute to 200 mL and mix it well.
4.2.16 Lead acetate cotton: soak the medical absorbent cotton in the lead acetate solution (4.2.15)
for 1 hour, squeeze out the excess lead acetate solution, make it loose, and naturally dry it, or
dry it at 90 C ~ 100 C, and store in an airtight bottle.
4.2.17 Sodium hydroxide solution (200 g/L): weigh-take 200 g of sodium hydroxide, add 500
mL of water to dissolve it, then, use water to dilute to 1,000 mL and mix it well.
4.2.18 Sulfuric acid solution (6%): measure-take 60 mL of sulfuric acid, slowly add 500 mL of
water. After cooling, use water to dilute to 1,000 mL, and mix it well.
4.2.19 Arsenic standard stock solution (0.1 mg/mL, calculated by arsenic): accurately weigh-
take 0.1320 g (accurate to 0.0001 g) of arsenic trioxide (CAS: 1327-53-3, purity  99.5%) that
has been dried at 100 C for 2 hours, and add 5 mL of sodium hydroxide solution (4.2.17) to
dissolve it, then, add 25 mL of sulfuric acid solution (4.2.18) and transfer to a 1,000 mL
volumetric flask. Use newly boiled and cooled water to reach a constant volume and mix it well.
Store it in a plastic bottle and in the dark at 2 C ~ 8 C. The shelf life is 12 months. Alternatively,
purchase certified reference material of arsenic.
4.2.20 Arsenic standard intermediate solution (1 g/mL): accurately transfer-take 1 mL of
arsenic standard stock solution (4.2.19) into a 100 mL volumetric flask, add 1 mL of
hydrochloric acid solution (4.2.10), use water to reach a constant volume and mix it well. Store
it in a plastic bottle and in the dark at 2 C ~ 8 C. The shelf life is 1 month.
4.3 Instruments and Equipment
4.3.1 Spectrophotometer: with a wavelength accuracy of  2 nm.
4.3.2 Analytical balance: with an accuracy of 0.0001 g.
4.3.3 Electric drying oven: with a temperature control accuracy of  5 C.
4.3.4 Temperature controllable electric heating plate: with a temperature control accuracy of 
5 C.
4.3.5 Muffle furnace: with a temperature control accuracy of  15 C.
4.3.6 Graphite digestion instrument: equipped with matching polytetrafluoroethylene digestion
tube.
4.3.7 Arsine generation and absorption device (see Figure 1): consists of a 125 mL arsenic
reaction bottle with graduations, a 5 mL arsenic absorption tube, and an air guide tube
connecting the arsenic reaction bottle and the arsenic absorption tube. The arsenic reaction
bottle, air guide tube and arsenic absorption tube are connected with ground joints to ensure no
air leakage.
4.5.1 Preparation of specimen solution
4.5.1.1 Mixed acid digestion method
Carry out two tests in parallel. Respectively w...