ISO 7358 pdf free download

ISO 7358-2021 pdf free download.Essential oils of bergamot, lemon, bitter orange and lime, fully or partially reduced in bergapten- Determination of bergapten content by high-performance liquid chromatography (HPLC).
Add chloroform (5.3.1.1. approximately 8 ml) and shake carefully to dissolve the coumarin.
It can be necessary to prepare several dilutions of the test solution to obtain a chromatogram with comparable peak areas for bergapten and coumarin because the bergapten content in the essential oils is unknown (fully or partially reduced in bergapten). Choose the volume of the volumetric flask, the quantities of cournarin and the volume of chloroform so as to meet this requirement.
Using the same HPLC operating conditions established in 8.2.1.1.1. inject a suitable amount of the test solution so as to remain within the detector sensitivity range.
Measure the peak areas of the chromatogram.
Measure and record the peak areas of the chromatogram corresponding to bergapten (AJ and coumarin
(A ).
8.2.1.2 External standard method
Follow the procedure for the external standard method as specified in ISO 8432.
8.2.2 HPLC In reversed phase
8.2.2.1 Preparation of the reference solutions for calibration
8.2.2.1.1 General
For each calibration, use the stock solutions of bergapten and coumarin to prepare the standard solution. Store the standard solution in a cool place at 4 °C.
8.2.2.1.2 Stock solutions
As accurately as possible weigh 50 mg of bergapten into a 100 ml flask and make up to volume with the dilution solvent. Homogenize the solution then leave it for 3 mm in the ultrasonic bath to get stock solution. This stock solution contains almost exactly 500 mg/I of bergapten.
As accurately as possible weigh 50 mg of coumarin into a 50 ml flask and make up to volume with the elution solvent. Homogenize the solution then leave it for 3 mm in the ultrasonic bath to get stock solution. This solution contains almost exactly 1 000 mg/I of coumarin.
8.2.2.1.3 Working solutions
Using the stock solutions, prepare a standard range of eight calibration points for bergapten concentration: 1 mg/I. 2,5 mg/I, 5 mg/I, 10 mg/I, 25 mg/I, 50 mg/I, 100 mg/I and 200 mg/l.
— 1 mg/I standard solution: into a 50 ml flask, transfer 100 il of bergapten stock solution and 5 ml of coumarin stock solution then make up to volume with the dilution solvent.
— 2,5 mg/I standard solution: into a 50 ml flask, transfer 250 il of bergapten stock solution and 5 ml of coumarin stock solution then make up to volume with the dilution solvent.
— 5 mg/I standard solution: into a 50 ml flask, transfer 500 uI of hergapten stock solution and 5 ml of coumarin stock solution then make up to volume with the dilution solvent.
— 10 mg/I standard solution: into a 50 ml flask, transfer 1 ml of bergapten stock solution and 5 ml of coumarin stock solution then make up to volume with the dilution solvent.
— 25 mg/I standard solution: into a 50 ml flask, transfer 2,5 ml of bergapten stock solution and 5 ml of coumarin stock solution then make up to volume with the dilution solvent.
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Iso 7358:2021(E)
— 50 mg/I standard solution: into a 50 ml flask, transfer S ml of bergapten stock solution and 5 ml of coumarin stock solution then make up to volume with the dilution solvent.
— 100 mg/I standard solution: into a 50 ml flask, transfer 10 ml of bergapten stock solution and 5 ml of coumarin stock solution then make up to volume with the dilution solvent.
— 200 mg/I standard solution: Into a 50 ml flask, transfer 20 ml of bergapten stock solution and S ml of coumarin stock solution then make up to volume with the dilution solvent.
Homogenize each prepared standard solution by stirring then pass through a 0,45 Im PTFE filter into a vial before injection in the H PLC.
8.2.2.2 Preparation of citrus essential oils samples
To determine the content of citrus essential oils with the standard range created previously (8.2.2.1.3), it is necessary to dilute the samples before injection in the HPLC.
Into a 10 ml flask, accurately weigh 0,3 g of essential oil of bergamot and 1 ml of coumarin stock solution (8.2.2.1,2). Make up to volume with the dilution solvent (5.3.2.4).
For the essential oils with low bergapten content, adapt the test portion. For example, in a 10-mI flask, weigh accurately about 4 g of bergamot essential oil partially reduced in bergapten and weigh accurately about 1 ml of coumarin stock solution. Fill to volume with dilution solvent (5..12A).
Homogenize each prepared sample by stirring then pass through a 0,45 lIm PTFE filter into a vial before injection in the HPLC.
8.2.2.3 Determination by HPLC and internal standardization of bergapten content in essential
oils of bergamot
The HPLC experimental conditions are:
— Injection volume: 10 uI.
— Oven temperature: 25 °C.
— Eluent flow rate: I mI/mm.
— UV detection conditions: diode-array LJV detection system, wavelengin = i2 nm.ISO 7358 pdf download.