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UDC 668.5
IS0
I N T E R NAT1 O NAL O R GAN I ZATl O N FOR STAN DAR D I ZATl O N
I S O R E C O M M EN DATI O N
R 280
DETERMINATION OF THE REFRACTIVE INDEX
OF ESSENTIAL OILS
1st EDITION
November 1962
COPYRIGHT RESERVED
The copyright of IS0 Recommendations and IS0 Standards
belongs to IS0 Member Bodies. Reproduction of these
documents, in any country, may be authorized therefore only
by the national standards organization of that country, being
a member of ISO.
For each individual country the only valid standard is the national standard of that country.
Printed in Switzerland
Also issued in French and Russian. Copies to be obtained through the national standards organizations.
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BRIEF HISTORY
The IS0 Recommendation R 280, Determination of the Refractive Index of Essential Oils,
was drawn up by Technical Committee ISO/TC 54, Essential Oils, the Secretariat of which is
held by the Repartiçao de Normalizaçao (IGPAI).
Work on this question by the Technical Committee began in 1953 and led, in 1957, to the
adoption of a Draft IS0 Recommendation.
This first Draft IS0 Recommendation (No. 88) was circulated to all the IS0 Member Bodies
for enquiry. As the results of this consultation were not considered satisfactory, the Technical
Committee presented a second Draft IS0 Recommendation, which was circulated to all the
Member Bodies in April 1960 and was approved by the following Member Bodies:
Australia France
New Zealand
Austria Greece Portugal
Belgium Israel Romania
Burma Italy Spain
Canada Japan Sweden
Chile Mexico
United Kingdom
Czechoslovakia Netherlands
U.S.S.R.
Yugoslavia
One Member Body opposed the approval of the Draft: India.
The Draft IS0 Recommendation was then submitted by correspondence to the IS0 Council,
which decided, in November 1962, to accept it as an IS0 RECOMMENDATION.
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ISOlR 280 - I962 (E)
R 280 November 1962
IS0 Recommendation
DETERMINATION OF THE REFRACTIVE INDEX
OF ESSENTIAL OILS
1. SCOPE
This IS0 Recommendation specifies the method to be used in determining the refractive index
of essential oils.
2. DEFINITION
The refractive index of an essential oil means the ratio of the sine of the angle of incidence to
the sine of the angle of refraction, when a ray of light of defined wave length passes from air into
the essential oil kept at a constant temperature.
The wave length is 589.3 2 0.3 nm (nanometre) corresponding with the Dl and D2 lines of the
sodium spectrum.
The reference temperature is 20 OC, except for those oils which are not liquid at this temperature.
In this case, a temperature of 25 OC or 30 OC, depending on the melting point
...