Specialized instrument for the new national standard sulfur dioxide in food (method for determining sulfur dioxide in Chinese Pharmacopoeia) prepared for use: ST109AST109BBST109CST109D full-series standard automatic reagent addition test, automatic nitrogen blowing control function (the first of its kind in the country)!!!
R&D background:
With the promulgation of the new national standard GB5009.34-2022 “Determination of Sulfur Dioxide in Food”, the determination methods for sulfur dioxide in food and for sulfur dioxide in Chinese medicinal materials in the Chinese Pharmacopoeia are largely consistent. Jinan Shengtai Technology, based on the new national standard and the Pharmacopoeia methods, has jointly developed four dedicated testing instruments: ST109A、ST109B、ST109C、ST109D. Among them, ST109A is the first fully automatic dedicated testing instrument in China.
It fully complies with the new national standard for sulfur dioxide in food and the 2016 and 2020 editions of the Chinese Pharmacopoeia methods.
Product Features:
* Heating method: automatic far-infrared ceramic heating tube management system, automatic anti-dry-burn technology;
* Cooling method: compressor cooling cycle for temperature reduction, fast cooling speed;
* Condenser tube design: semi-hidden clamp-free national-standard dedicated reflux condenser tube;
* Control system: automatic temperature rise technology, micro-boiling and full-boiling heating modes can be set; automatic timing 0-999min;
* Reagent addition: high-precision reagent injection pump can automatically complete reagent addition, no manual operation required;
* Nitrogen control: high-quality nitrogen average distribution system, automatically adjusts nitrogen flow rate, not a common rotameter flowmeter;
* Titration system: automatic titration using sodium hydroxide standard solution;
* Endpoint recognition: automatically recognizes the titration endpoint and automatically calculates the test results.
Comparison of new and old national standard testing methods for the determination of sulfur dioxide in food (Method 1) |
| GB5009.34-2016 | GB5009.34-2022 (New National Standard) |
| Detection methods | Titration method | The titration method has been revised to: acid-base titration method, with the second method adding spectrophotometry and the third method adding ion chromatography. |
| Scope of testing | This standard specifies methods for determining total sulfur dioxide in foods such as fruit preserves, dried vegetables, rice flour products, noodles, sugar, edible fungi, and wine. | Method 1 is the acid-base titration method, applicable to the determination of sulfur dioxide in food; Method 2 is the spectrophotometric method, and the direct extraction method is applicable to the determination of sulfur dioxide in colorless samples without fat and without color interference in the extraction solution, such as white sugar and white sugar products, starch and starch products, and fresh wet noodle products; the nitrogen blowing distillation extraction method is applicable to the determination of sulfur dioxide in colored samples such as grape wine and brown sugar; Method 3 is the ion chromatography method, applicable to the determination of sulfur dioxide in food. |
| Sample preparation | 5 g of homogenized sample (accurate to 0.001 g, the sampling amount can be determined according to the content level); for liquid samples, directly pipette 5.00 mL to 10.00 mL of sample; add 250 mL of water; add 10 mL of hydrochloric acid. | Take 20 g to 100 g of solid or semi-solid sample (accurate to 0.01 g, the sampling amount can be determined according to the content level); take 20 mL(g) to 200 mL(g) of liquid sample; add 20-500 mL of water; add 10 mL of 6 mol/L hydrochloric acid. |
| Whether to enrich by nitrogen blowing | No | Nitrogen blowing enrichment, flow rate: 1.0-2.0 L/min |
| Absorption solution | 25 mL lead acetate absorption solution | 50 mL 3% hydrogen peroxide solution (Method 1) |
| Distillation method | Collect 200 mL of distillate, then distill for 1 minute, and rinse the insertion tube of the absorption solution device with a small amount of distilled water. | Heat the solution in the flask to boiling and maintain gentle boiling for 1.5 h. |
| Titration method | Add 10 mL of hydrochloric acid and 1 mL of starch indicator solution to the titration flask in sequence. After shaking well, titrate with sodium thiosulfate standard solution until the solution turns blue and does not fade within 30 s. At the same time, perform a blank test. | After cooling the absorption solution, shake well. Add 3 drops of 2.5 mg/mL methyl red and methylene blue mixed indicator solution to the absorption solution, and titrate with sodium hydroxide standard solution (0.01 mol/L) until the solution turns yellow and does not fade within 20 seconds. Perform a blank test at the same time. |
| Detection limit and quantitation limit | When 5 g solid sample is taken, the method's detection limit (LOD) is 3.0 mg/kg and the quantitation limit is 10.0 mg/kg; when 10 mL liquid sample is taken, the method's detection limit (LOD) is 1.5 mg/L and the quantitation limit is 5.0 mg/L. | When 0.01 mol/L sodium hydroxide titrant is used, and the solid or semi-solid sample mass is 35 g, the detection limit is 1 mg/kg and the quantitation limit is 10 mg/kg; when the liquid sample amount is 50 mL(g), the detection limit is 1 mg/L (mg/kg) and the quantitation limit is 6 mg/L (mg/kg). |
| Product recommended models | ST106-1RW (distillation pretreatment), ST106K2 (fully automatic, can directly output test results.) | Full ST109 series (A is six-digit, fully automatic model, directly output test results; B is six-digit; C is eight-digit, high cost-performance model; D is ion chromatography water vapor distillation dedicated machine), the full series is equipped with automatic acid addition and nitrogen control device (A uses digital inlet nitrogen controller, other models use rotameter). The full series is compatible with testing sulfur dioxide in Chinese medicine and Chinese medicinal materials. |