New national standard food sulfur dioxide ("Chinese Pharmacopoeia" method to detect sulfur dioxide in traditional Chinese medicine) supporting special instruments: ST109A, ST109B, ST109C, ST109D all series are equipped with automatic reagent addition and automatic nitrogen blowing control functions (the first in the country)! ! !
R & D background:
The new national standard GB5009.34-2022 "Determination of Sulfur Dioxide in Food" was promulgated, and the third method is: ion chromatography.
Principle of the method:
The sulfite series substances in the sample are converted into sulfur dioxide by acid treatment, distilled out with water vapor through nitrogen-filled steam distillation, absorbed by hydrogen oxide solution and oxidized to generate sulfuric acid, and the sulfate ions in the solution are separated by ion chromatography column , Conductivity detector detection, external standard method for quantification.
Steps:
Weigh 10g of a solid or semi-fluid sample (accurate to 0.01g), place it in the round-bottomed flask D in Figure B.1, add 50mL of water, and shake to make the dispersion even; switch on nitrogen protection, and control its flow rate to 1.0 L/min～2.0L/min. Connect the steam distillation bottle A, add 20mL of 3% hydrogen peroxide solution (3.2.1) into the absorption bottle H (100mL Nessler colorimetric tube) as the absorption liquid, and insert the lower end of the absorption tube below the liquid level of the absorption liquid. Quickly add 10mL of hydrochloric acid solution (6mol/L) (3.2.2) to bottle D along the wall of the bottle, quickly close the plug , start distillation, keep bottle A boiling and adjust the distillation firepower, 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 joint tube with water and transfer it to a 100mL volumetric flask, adjust the volume to the mark with water, shake well, let it stand for 1h, filter it with a microporous membrane (0.45μm) to obtain the sample solution to be tested. Do not add sample, do blank test in the same way.
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, an automated steam distillation device is urgently needed 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:
* True integrated design, the inner cavity of the host is designed with an independent steam chamber, which automatically generates water vapor;
* Automatic acid dosing setting, each channel can be independently controlled, can be set to the acid dosing volume, can perform acid dosing accuracy calibration, pipeline cleaning and other functions;
* 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. After reaching the set value, the heating can be automatically stopped and an audible and visual alarm will be given;
