Quality control methods for

Determination by gas chromatography 
A capillary gas chromatograph with an ECD is used for the measurement. 
Helium R is used as the carrier gas and a mixture of argon R and methane R 
(95:5) as an auxiliary gas for the detection. 
First separation system 
Use a vitreous silica column, 30 m long with an internal diameter of 0.25 mm, 
packed with a chemically bound phase of 5% phenyl, 95% methyl-polysiloxane. 
Use the following temperature programme: 
- 
heat at 60°C for 0.5 minutes; 
- 
increase the temperature at a rate of 30°C per minute to 160°C and 
maintain this temperature for 2 minutes; 
- 
increase the temperature at a rate of 2°C per minute to 250°C and 
maintain this temperature for 5 minutes. 
Use a "split/split-free" injector to inject the sample solution and maintain the 
injection port at a temperature of 240°C. Inject a volume of 1 µl at a rate of 30 
seconds ("split-free"). The detector temperature should be 300°C. 
Second separation system 
Use a vitreous silica column, 15 m long with an internal diameter of 0.25 mm, 
packed with a chemically bound phase of 7% cyanopropyl, 7% phenyl, 86% 
methyl-polysiloxane. Use the following temperature programme: 
- 
heat at 60°C for 0.2 minutes; 
- 
increase the temperature at a rate of 30°C per minute to 180°C and
maintain this temperature for 1 minute; 
- 
increase the temperature at a rate of 2°C per minute to 250°C and
maintain this temperature for 5 minutes. 
Use an on-column injector to inject a volume of 1 µl of the sample solution. The 
detector temperature should be 300°C. 
Use the "external standard" method for the qualitative and quantitative 
evaluation of the organochlorine pesticides in the test solutions with reference 
solutions of the following pesticides: α-, β-, γ- and δ-hexachlorocyclohexane 
(HCH); hexachlorobenzene; quintozene; aldrin; dieldrin; endrin; α- and β-
endosulfan; endosulfan sulfate; heptachlor, heptachlorepoxide; camphechlor;
TDE, DDE and DDT (both o,p'- and p,p'-isomers); methoxychlor. 
Measure the peak height of the pesticides obtained in the chromatograms and 
calculate the concentration of the residues in mg/kg using the following 
formula: 
r
r
t
h
w
x
w
h  x10

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Quality control methods for medicinal plant materials 
where h
t 
= peak height obtained for the test solution in mm,
w = quantity of sample in the purified extract (g), 
w
r
= quantity of pesticide in ng in the reference solution injected,
h
r
= peak height obtained for the reference solution in mm.