1 Reagents and equipment
① Ferric chloride (HG3-1085-77). 1% solution, dissolve 1.08% analytically pure blue ferric chloride in water, and dilute to ]00 ml.
② Ammonium thiocyanate (GB 660-78). 2% solution, dissolve ⒉0 g of analytically pure ammonium thiocyanate in water, and dilute to 100 ml.
③Drip bottle. When the dropper is tilted at an angle of 45°, the volume of each drop is 0.06 ml.
④ Petri dish.
⑤ stopwatch.
2 test steps
① Carry out sampling according to the standard method.
②According to the standard method for temperature and humidity treatment.
③ Sample preparation. Cut the sample into a 30 mm × 30 mm paper pattern, at least 10 test pieces. Fold the four sides of the paper pattern to make a boat with a base of about 20 mm×20 mm. Among them, half face up!:, and half face down.
④ Pour an appropriate amount of ammonium thiocyanate solution into the culture tank, then float the boat on the liquid surface of the ammonium thiocyanate solution, and at the same time use a dropper to drop 1 drop of ferric chloride solution into the boat, and start immediately Stop the watch until a red dot appears in the ferric chloride solution and stop the watch. Remember the time is accurate to ls.
Note: During operation, the dropper is inclined at an angle of about 15°, and the nozzle is about 1 cm away from the paper surface. 06ml。 Each turbulent liquid volume is about 0. 06ml.
3 result calculation
The average value of all measured values on the front and back sides. and coefficient of variation.
