a study of the quality of a local herbal tea and volatiles of parinari ...

3.4 Preparation of chemicals and reagents
3.4.1 Sodium hydrogen carbonate (aq) solution (2.5 %, m/v)
Sodium hydrogen carbonate (NaHCO3) (2.5 g), placed in a 100 ml volumetric flask and
made up to mark with triple distilled water.
3.4.2 Saturated aqueous oxalic acid solution
Oxalic acid (10 g) was weighed and placed in a 100ml volumetric flask. The solution was
made up to the mark with triple distilled water and stored at room temperature.
3.4.3 Methanol solution (60 %, m/v)
Methanol (60 ml) was diluted to 100 mL with triple distilled water and shaken thoroughly
to ensure homogeneity of the solution. From this solution the following methanol
solutions were prepare as follows:
Solution 1: Thirty millilitres of methanol (60 %, m/v) were mixed with triple distilled
water (16 mL) in a 100 ml Schott bottle.
Solution 2 was made by adding 30 ml of 60% Methanol to 12 ml of triple distilled water
and 4 ml of oxalic acid in 100 ml Schott bottle.
3.5 Determination of moisture content of F. ancylantha and Lipton control teas
Moisture was determined using the (ISO Tea determination loss in mass at 103 0 C: 1980)
method. Determination of moisture content was done in duplicate. Crucibles were dried
in the oven overnight at 103 0 C, cooled in a desiccator and weighed to at least 0.001 g.
Tea sample (5 g) was placed in each crucible in duplicate. Crucibles and tea leaves were
placed in the oven for 12 hours at 103 0 C, cooled in a desiccator and accurately weighed.
The percentage of moisture content of the teas was calculated by subtracting the loss in
mass of the tea leaves after drying and expressing it as a percentage of the initial mass.
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