Quality control methods for

Sodium hydroxide (0.5 mol/l) VS. Sodium hydroxide R dissolved in water to 
produce a solution containing 20.00g of NaOH in 1000 ml. 
Method of standardization. Ascertain the exact concentration of the solution 
following the method described under sodium hydroxide (1 mol/l) VS. 
Sodium hydroxide (0.1 mol/l) VS. Sodium hydroxide R dissolved in water to 
produce a solution containing 4.001 g of NaOH in 1000 ml. 
Method of standardization. Ascertain the exact concentration of the solution 
following the method described under sodium hydroxide (1 mol/l) VS. 
Sodium hydroxide (0.05 mol/l) VS. Sodium hydroxide R, dissolved in water to 
produce a solution containing 2.000g of NaOH in 1000ml. 
Method of standardization. Ascertain the exact concentration of the solution 
following the method described under sodium hydroxide (1 mol/l) VS. 
Sodium hydroxide (0.02 mol/l), carbonate-free, VS. Sodium hydroxide R, 
dissolved in water to produce a solution containing 0.8001 g of NaOH in 1000 
ml.
Method of standardization. Ascertain the exact concentration of the solution 
following the method described under sodium hydroxide (1 mol/l) VS. 
Sodium hydroxide, methanolic TS. 
Procedure. Dissolve 2.5 g of sodium hydroxide R in 10ml of carbon-dioxide-free 
water R. Add 1 ml of propylene glycol R and dilute to 100 ml with methanol R. 
Sodium hypochlorite TS. Containing 100-140g of available chlorine per litre. 
Description. A yellowish liquid; odour of chlorine. 
A suitable commercially available reagent. 
Sodium metabisulfite R. Na
2
O
5
S
2
. 
A suitable commercially available reagent. 
Sodium metabisulfite (150 g/l) TS. A solution of sodium metabisulfite R 
containing about 150g of Na
2
O
5
S
2
per litre. 

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Quality control methods for medicinal plant materials