1. Scope
The standards stipulate technical requirements, experiment methods, inspection rules and other requirements on packing, mark, transportation and storage of the food additive -- tertiary butylhydroquinone.
The standards apply to tertiary butylhydroquinone (TBHQ in short) used as antioxidant in the food industry, which is produced with hydroquinone as raw material after alkylation reaction.

2．Standards quoted
Clauses included in the following standards constitute the ones of the standards through being quoted in the standards. When the standards are published, editions shown are valid. All standards will be amended. All parties who use the standards should discuss the possibility of using the latest editions of the following standards.
GB8450-87 Method of determining arsenic in food additives
GB8451-87 Experiment method to find limit amount of heavy metal in food additives
GB617-88 Chemical reagent general method of determining the scope of melting point

3．Constitutional formula、molecule formula、molecule weight
Constitutional formula：
Molecular formula： C₁₀H₁₄O₂
Comparative molecular formula：166.22
4．Technical requirements
4．1 Appearance
White crystal powder with a special odor.
4．2 Physico-chemical index should meet requirements in Table 1.
表1

5. Experiment method
When there is no special requirement, reagents and water used in the standard are pure reagents for analysis and distilled water or water with certain purity.
5. 1 Discrimination
Put several mg samples into 1ml methyl alcohol, add several drops of 25% dimethylamine water solution and the solution turns from pink into red and cannot be deoxidated.
5. 2 Determination of contents of TBHQ, t-Buty1-p-benzoquinone, 2,5-di-t-butylhydroquinone and hydroquinone.
5．2．1 Reagents
-- absolute ethyl alcohol；
-- hydroquinone：standard sample；
-- t-Buty1-p-benzoquinone：standard sample；
--TBHQ：standard sample；
--2,5-di-t-butylhydroquinone：standard sample。
5．2．2 Instruments
a) gas chromatograph with hydrogen flame ionized detecting instrument and automatic integrator；
b) chromatographic column：elastic quartz capillary pole with total theoretical plate number of over 60 thousand. Stationary phase is OV-101（for example, HP—1，30m/0.32mm）. Under operation conditions, 2,5-di-t-butylhydroquinone and TBHQ should reach base line separation.

5．2．3 Operation conditions
a) air current speed：carrier gas is hydrogen, line speed is 30cm/s；
b) temperature：column temperature 220℃，injector 260℃，detecting instrument 260℃；
c) shunting：10：1。
5．2．4 Determination
Weigh 0.2g sample（accurate to 0.0002g）and add 1mL ethyl alcohol to make the sample solution. Inject 0.6μL sample under the above conditions, record it with the integraph, calculate in accordance with the normalizing method and show automatically relevant contents. Before this, standard hydroquinone, t-Buty1-p-benzoquinone, TBHQ and 2,5-di-t-butylhydroquinone should be used to determine the preservation time of corresponding compounds.
5．3 Determination of toluene
5．3．1 Reagent
-- Diethyl phthalate；
--Toluene（analytical reagent）.
5．3．2 Instruments
a) gas chromatograph：the same as 5.2.2a).
b) chromatographic column： 2m long，packed column with 3mm inner diameter， stuffing is FFAP：chromosorb W(80~100 item)is 10：100.
5.3.3 Operation conditions
a) air current speed: carrier gas is hydrogen，40mL/min；
b) temperature：pole temperature 70℃，injector 200℃，detecting instrument 200℃。
5．3．4 Determination
Weigh 2g samples（accurate to 0.0002g）and put them into a 25ml glass bottle with plastic lid. Add 10ml diethyl phthalate. Cover the bottle with the lid and shake up the solution fully. put the bottle onto the bain-marie at 60℃ to keep balance for 20 minutes. Under the above operation conditions, imbibe 2ml gas in the bottle for analysis. Inject 10ml diethyl phthalate each ml of which contains 5μg toluene into another glass bottle as comparison solution. Make analysis under the same important conditions. Calculate with the Intergraph according to external standard method and show the contents of toluene in the sample.
5．4 Determination of arsenic
Carried out according to GB8450.
5．5 Determination of heavy metal
Carried out according to GB8451.
5．6 Determination of melting point
Carried out according to GB617.
6．Inspection rules
6．1 Products should pass the inspection conducted by manufacturers’ quality control departments according to the standards, and be attached with quality certificates before they leave factory or are packed and stored in warehouses.
6．2 Enterprises who use the products can carry out quality inspection according the standards.
6．3 Sampling method：taking products of the same production cycle as a batch, samples should be chosen from 10% of each batch. When the quantity of the batch is small, the minimum of sampling should not be less than three bags. Insert instruments such as a sampling needle into 3/4 depth of each bag chosen and take out the sample that weighs no less than 50g. The total weight of all samples should not be less than 500g. mix the samples quickly and condense them into 250g by means of quartering. Put them into a clean and dry wide-mouth bottle with socket and attach onto the bottle the label which marks the manufacturer’ name, product batch number and the sampling date. Send the bottle to the laboratory for analysis.
6．4 Contents of TBHQ, t-Buty1-p-benzoquinone, 2,5-di-t-butylhydroquinone, hydroquinone、toluene and melting point are must items for inspection. Other indexes are model items for inspection which are under inspection per three months. If there is one index which fails to meet the standards in the inspection, samples should be chosen again from bags whose weight is twice of that last time for reinspection of all items. Even if there is only one index that does not meet the standards in the result of the reinspection, the batch will be considered unqualified.
6．5 All disputes arising from the buyer and the seller in connection to the quality of products may be submitted to quality arbitration organizations.
7．Mark, packing, transportation, storage
7．1 Mark
Package should be marked with the manufacturer’s name, address, the name of the product, trademark, product model, batch number, production date, shelf life, major parameters of the product, net amount, standard number of the product and the words “Food Additive”.
7．2 Packing
Products should be packed in foil bags with vacuum encapsulation. One kg for each bag. Average weight of per 100 bags should not be less than the total of average weights shown of the 100 bags.
7．3 Transportation
Handle with care during transportation. Avoid being effected by damp and heat.
7．4 Storage
Products should be kept in cool and dry places. Avoid piling them with poisonous and harmful substances. Shelf life is 18 months.
VIII Analysis of quality index of TBHQ
1．2,5- DTBHQ and HQ
（1）Instruments adopt gas chromatography equipped with thermal conductivity detecting instrument（such as F and M model 810），stainless steel pole 0.61m(length)×6.35mm（outer diameter），containing 20% silicon SE-30（poidometer） and 80% Diatoport S （60/80 item）。
（2）Operation conditions: the temperature of the pole rises in proper sequence from 100℃（15℃/min）to 270℃. Injection port temperature, 300℃。Carrier gas, helium. Flux 100ml/minute. Bridge electricity, 140mA。Sensitivity (integraph Infotronics CRS-100) is ×1；recorder×2。
（3）Solution
（i）Base solution Weigh accurately 50mg HQ, DTBHQ and methyl benzoate (internal label) respectively. Add them to three 50ml volumetric flasks separately. Shake them up after constant volume with pyridine.
（ii） Standard solution for correction Put 0.50、1.0、2.0 and 3.0ml HQ base solution in four 10ml volumetric flasks respectively. Add 2ml methyl benzoate in each flask. Shake them up after constant volume with pyridine. Make four DTBHQ correction solutions in the same way. Prepare TMS with each solution in the following way. Put one drop of the base solution into a 2ml gas injector, add 250μl N,O-Bistrimethyl silyl caproamide and heat the mix at about 80℃ for 10 minutes. Take 10μl of each standard solution for chromatogram analysis and repeat. Draw a curve with concentration ratio of HQ to internal standard solution as X axis and with response ratio of HQ internal standard as Y axis. Draw the curve of DTBHQ and internal standard solution in the same manner.
（4）Operation Weigh accurately about 1g sample and put it into a 10ml volumetric flask. Add 2ml internal standard solution of methyl benzoate into the flask. Shake them up after constant volume with pyridine. Prepare TMS following the method of the above standard solutions for correction. Inject 10μl samples repeatedly for chromatogram analysis and draw the chromatogram map. Average time for a peak to show up is: methyl benzoate 2.5 minutes; HQ’s TMS 5.5 minutes; TBHQ’s TMS 7.3 minutes; DTBHQ’s TMS 8.4 minutes.
（5）Calculation calculate the area of each peak with automatic integraph or manual trigonometry (repeat once). Calculate again the ratio of HQ and DTBHQ to internal standard. Seek concentration ratio of HQ and DTBHQ to internal standard from correction curve and work out the percentage (A) of HQ and DTBHQ in the sample according to the following formula:

In the formula Y—concentration ratio（X axis in the correction curve）；
I—the percentage of internal standard prepared with the sample（W/V）；
S— weight of the sample, g.
2. Tert-butyl-p-benzoquinone（TBBQ）
（1） Instruments Adopt double light beam infrared spectrophotometer, equipped with 0.4nm liquid test pool with calcium fluoride window.
（2） solution
（i）Preparation of standard solution Weigh accurately 10mg mono-tert-butyl-p-benzoquinone (MTBBQ) reference standard, put it into a 10ml volumetric flask, dissolve it with chloroform before constant volume and shake them up.
（ii）Preparation of sample solution Weigh about 1g sample which has been grinded into powder by high-speed disintegrator. Put it into a 10ml volumetric flask, dissolve it with chloroform before constant volume and shake them up. Filtrate the solution with millipore filter (such as UHWPO 1300) before determination is carried out。
（3）Operation Fill the colorimetric pool with chloroform and fill the sampling pool with standard preparation solution. 1600~1775cm^-1. In the scope of 1612~1750cm^-1 background light, determine the net absorbance (As) of the standard preparation solution at 1659cm-1. Obtain the spectrum of the sample preparation solution in the same way and determine its net absorbance (Au) at 1659cm^-1. The percentage of TBBQ content in the sample is:


In the formula, Ws—weight of MTBBQ with the standard sample as reference: mg;
Wu— weight of the sample: mg.

３．Toluene
I．FAO/WHO method
（１）Instruments　 Use gas chromatography equipped with flame ion detector (such as F and M model 810), connected with a 3.66m×3.18mm stainless steel column (outer diameter) which contains 10% Silicone SE-30 (poidometer), and 90% Diatoport (60/80 item).
（2）Operation conditions Column temperature rises in proper sequence from 70℃ to 280℃, 15℃/min。Injection port temperature 275℃； photronic cell temperature 300℃；the conditions of H2 and O2 are 1.42 Mpa separately.
（3）Solution
（i） Standard solution Prepare the octyl solution containing about 50μg/ml toluene and work out accurate concentration (Cr) shown in percentage.
（ii）Sample solution Weigh about 2g sample accurately, put it into a 10ml volumetric flask, dissolve it with octyl alcohol before constant volume, and shake them up. Work out the percentage (W/V) of accurate concentration (Cs) of the sample solution.
（4）Operation Inject 5ml standard solution into chromatograph and determine the peak height (Hr) of toluene peak. The demurrage of tuloene is 3.3 minutes. Other peaks are invalid in the experiment. Following the same method, use octyl alcohol as blank sample to work out chromatogram of 5μl sample solution and calculate peak height (Hs) of toluene peak. The contents of toluene in the sample should be calculated according to the following formula.


II．QB2395 method
（1）Instruments
Gas chromatogram; the same as II in analysis of contents. Chromatogram column： 2m long, packed column with 3mm inner diameter, stuffing FFAP：chromosorb W（80~100 item） is 10:100。
（2）Operation conditions
Air current speed: carrier gas is hydrogen，40mL/min；
temperature：column temperature 70℃，injector 200℃，detecting instrument 200℃.
（3）Determination Weigh 2g samples（accurate to 0.0002g）and put them into a 25ml glass bottle with plastic lid. Add 10ml diethyl phthalate. Cover the bottle with the lid and shake up the solution fully. put the bottle onto the bain-marie at 60℃ to keep balance for 20 minutes. Under the above operation conditions, imbibe 2ml gas in the bottle for analysis. Inject 10ml diethyl phthalate each ml of which contains 5μg toluene into another glass bottle as comparison solution. Make analysis under the same important conditions. Calculate with the Intergraph according to external standard method and show the contents of toluene in the sample.

Appendix C “Taibang Brand”TBHQ toxicologic experiment

Appendix D inspection data of“Taibang Brand”TBHQ
（Note：attached figure “inspection data”）。