Quality control methods for

Neutral red R. C.I. 50040; C.I. Basic red; C
15
H
17
ClN
4
. A suitable commercially 
available reagent. 
 
Nitric acid, fuming, R. HNO
3
. 
A suitable commercially available reagent. 
 
Nitric acid (∼1000 g/l) TS. d ∼ 1.41. 
A suitable commercially available reagent. 
Nitric acid (∼750 g/l) TS. 
Procedure. Dilute 750ml of nitric acid (∼1000g/l) TS with sufficient water to 
produce 1000ml (approximately 12mol/l). 
Nitric acid (∼500g/l) TS. 
Procedure. Dilute 500ml of nitric acid (∼1000 g/l) TS with sufficient water to 
produce 1000 ml (approximately 8 mol/l). 

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Quality control methods for medicinal plant materials 
Nitric acid (∼225 g/l) TS. 
Procedure. Dilute 225 ml of nitric acid (∼10008/l) TS with sufficient water to 
produce 1000 ml (approximately 3.5mol/l). 
Nitro-chromic acid TS. 
Procedure. Mix equal volumes of nitric acid (∼225g/l) TS and chromic acid TS. 
Nitrogen R. N
2
. 
A suitable commercially available reagent. 
Ox bile, dehydrated, R. Dehydrated, purified fresh bile.
A suitable commercially available reagent. 
Pancreatic digest of casein R. 
A suitable commercially available reagent. 
Pancreatic digest of gelatin R. 
A suitable commercially available reagent. 
Papaic digest of soybean meal R. 
A suitable commercially available reagent. 
 
Paraffin, liquid, R. 
A suitable commercially available reagent. 
Peptone, dried, R. A variety of peptones are available from casein, meat, beef or 
a mixture of these. 
A suitable commercially available reagent.