New national standard food sulfur dioxide ("Chinese Pharmacopoeia" method to detect sulfur dioxide in traditional Chinese medicine) supporting special equipment: ST109A, ST109B, ST109C, ST109D are all standard equipped with automatic reagent addition and automatic nitrogen blowing control function (the first in the country)! ! !
R&D background:
The new national standard GB5009.34-2022 "Determination of Sulfur Dioxide in Food" was promulgated, of which the third method is: ion chromatography.
Method principle:
The sulfite series substances in the sample are converted into sulfur dioxide by acid treatment, which is distilled out with water vapor through nitrogen-filled steam distillation, absorbed by hydrogen oxide solution and oxidized to generate sulfuric acid, and sulfate ions in the solution are separated by ion chromatography column. , Conductivity detector detection, external standard method for quantification.
Steps:
Weigh 10g of solid or semi-fluid sample (accurate to 0.01g), put it in the round-bottom flask D in Figure B.1, add 50mL of water, shake to make the dispersion evenly; switch on nitrogen protection, control its flow rate to 1.0 L/min～2.0 L/min. Connect the steam distillation bottle A, add 20mL of 3% hydrogen peroxide solution (3.2.1) to the absorption bottle H (100mL Nessler colorimetric tube) as the absorption solution, and insert the lower end of the absorption tube below the liquid level of the absorption solution. Quickly add 10 mL of hydrochloric acid solution (6 mol/L) (3.2.2) to bottle D along the bottle wall, quickly seal the plug , start distillation, keep bottle A boiling and adjust the distillation power, so that the outflow rate of the distillate at the end of the absorption tube is about 2mL/min. Distill until the total volume of the solution in bottle H is about 95mL (time 30min ~ 40min), wash the tail pipe with water and transfer it to a 100mL volumetric flask, make up to the mark with water, shake well, leave it for 1h, filter it with a microporous membrane (0.45μm) filtration to obtain the sample solution to be tested. No sample was added, and a blank test was performed in the same manner.
19.2.2 Liquid samples
Accurately measure 10mL~50mL liquid sample or weigh 10g~50g liquid sample (accurate to 0.01g). When the liquid sample is less than 50mL, add water to make up the volume to 50mL. Other operations are the same as 19.2.1.
Therefore, there is an urgent need for an automated steam distillation device in the market to replace the traditional manual operation, which can greatly simplify the distillation pretreatment process and improve labor efficiency. According to the description of the third method of GB5009.34-2022 "Determination of Sulfur Dioxide in Food", Jinan Shengtai Technology specially launched ST109, an intelligent integrated steam distillation apparatus.
Features:
* Real integrated design, the inner cavity of the host is designed with an independent steam chamber, which automatically generates water vapor;
* Automatic acid addition setting, each channel can be independently controlled, and can be set to the acid addition amount, and can perform functions such as acid addition accuracy calibration and pipeline cleaning;
* The equipment is equipped with an independent nitrogen flow control valve, the flow range: 200-2000ml/min;
* The end point of the distillate can be automatically set and controlled automatically. After reaching the set value, the heating can be automatically stopped and an audible and visual alarm will be given;
