Method I Direct Drying Method
2 Principle
Utilize the physical properties of the moisture in food to adopt volatilization method to
determine weight loss of the sample drying under 101.3kPa (1 atm) at 101 ℃ ~ 105 ℃,
including hydration moisture, part of crystalization moisture and substances that can
volatize under these conditions. Calculate the moisture content using weighted values
before and after drying.
3 Reagents and Materials
Unless otherwise noted, all the reagents used in this method are analytically purity
3.1 HCl (HCl): top-grade purity
3.2 NaOH (NaOH): top-grade purity.
3.3 HCl solution (6mol/L): Weigh 50mL HCl, dilute with water to 100mL.
3.4 NaOH solution (6mol/L): Weigh 24g NaOH, dissolve in water and dilute to 100mL.
3.5 Sea sand: Wash sea/river sand with water to remove the mud. Firstly boil the sand
with HCl (as prepared 3.3) for 0.5h and thenneutralize with water. Then boil the sand with
NaOH (as prepared 3.4) for 0.5h, neutralize with water and dry under 105℃ for use.