Special instruments for the new national standard food sulfur dioxide (Chinese Pharmacopoeia method for testing traditional Chinese medicine sulfur dioxide): ST109A, ST109B, ST109C, ST109D are all 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-steam distillation, absorbed by hydrogen peroxide solution and oxidized to generate sulfuric acid. The sulfate ions in the solution are separated by ion chromatography column, detected by conductivity detector, and quantified by external standard method.

Steps:

Weigh 10g of solid or semi-fluid sample (accurate to 0.01g), place it in the round-bottom flask D in Figure B.1, add 50mL of water, shake to make it evenly dispersed; connect nitrogen protection and control its flow rate to 1.0 L/min~2.0 L/min. Connect the water vapor distillation bottle A, add 20mL of 3% hydrogen peroxide solution (3.2.1) as the absorption liquid to the absorption bottle H (100mL Nessler colorimetric tube), and insert the lower end of the absorption tube below the surface of the absorption liquid. Quickly add 10mL of hydrochloric acid solution (6mol/L) (3.2.2) along the wall of bottle D, quickly seal it , start distillation, keep bottle A boiling and adjust the distillation fire 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, dilute to the mark with water, shake well, let stand for 1h, and filter with a microporous filter membrane (0.45μm) to obtain the sample solution. Do a blank test in the same way without adding the sample.

19.2.2 Liquid samples

Accurately measure 10mL~50mL of liquid sample or weigh 10g~50g of 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, the market is in urgent need of an automated steam distillation device to replace traditional manual operations, which can greatly simplify the distillation pretreatment process and improve labor efficiency. Jinan Shengtai Technology has launched the ST109 intelligent integrated steam distillation instrument based on the description of the third method of GB5009.34-2022 "Determination of sulfur dioxide in food".

Features:

* A truly integrated design, with an independent steam chamber inside the main unit to automatically generate steam;

* Automatic acid addition setting, each channel can be controlled independently, the acid addition amount can be set, and the acid addition accuracy calibration, pipeline cleaning and other functions can be performed;

* The equipment is equipped with an independent nitrogen flow control valve, flow range: 200-2000ml/min;

* The end point of the distillate can be automatically set and controlled. When the set value is reached, the heating will stop automatically and an audible and visual alarm will sound;