Quality control methods for

1. General notices 
General considerations 
The metric system is used throughout the text. All temperatures are expressed in 
degrees Celsius (°C). 
Tests are normally carried out at room temperature (between 15 and 25°C, or up 
to 30°C in some climatic zones), unless otherwise indicated. 
Any glassware used in the tests should be of suitable quality. Graduated and 
volumetric vessels should be calibrated at room temperature. 
When a water-bath is referred to in the text, a bath containing boiling water 
(about 100°C) is to be used, unless a specific water temperature is given. 
Unless otherwise specified, all solutions indicated in the tests are prepared with 
distilled or demineralized water of adequate purity. 
Reagents and solutions 
Reagents and solutions used must conform to the requirements specified in 
section 22 "Reagents and solutions", and are designated as follows: reagent, R; 
test solution, TS; volumetric solution, VS. 
Precision of measurement 
Quantities and volumes 
The quantities and volumes of the materials and reagents used in the tests must 
be measured with adequate precision, which is indicated in the following way: 
A value of: 20.0 means not less than 19.5 and not more than 20.5 
2.0 means not less than 1.95 and not more than 2.05 
0.20 means not less than 0.195 and not more than 0.205. 
Temperature 
Temperature measurement is indicated in a manner similar to that given for 
quantities and volumes. 
Storage conditions given in general terms refer to the following equivalent 
temperatures: 
In a refrigerator 
0-6 °C 
Cold or cool 6-15 °C 
Room temperature 15-25 °C, 
or up to 30°C depending on climatic zones. 

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Quality control methods for medicinal plant materials 
pH values 
Precision in the measurement of pH values is indicated in a manner similar to 
that for quantities and volumes.