Gum of Cistus ladaniferus (Cistaceae) obtained from stems and leaves by extraction with alkaline solution

Boiling point

Link to relevant study record(s)

Reference

Endpoint:

boiling point

Type of information:

experimental study

Adequacy of study:

key study

Study period:

May 22 to July 04, 2014

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Justification for type of information:

The study was conducted according to an internationally recognised method, and under GLP.
Restrictions apply considering the difficulty to interprete the result obtained for such complex substance and to determine the initial boiling point & temperature of decomposition of the substance. The substance is considered to be adequately characterised. Therefore a validation with restrictions applies.

Qualifier:

according to guideline

Guideline:

OECD Guideline 103 (Boiling point/boiling range)

Version / remarks:

dated 27. Jul. 1995

Deviations:

yes

Remarks:

A Cottrell vessel with three openings and an additional thermometer in the sample was used instead of a vessel with two openings. It allows to detect the temperature of the substance in the Cottrell vessel.

Qualifier:

according to guideline

Guideline:

EU Method A.2 (Boiling Temperature)

Version / remarks:

dated 31. May 2008

Deviations:

yes

Remarks:

A Cottrell vessel with three openings and an additional thermometer in the sample was used instead of a vessel with two openings. It allows to detect the temperature of the substance in the Cottrell vessel.

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Remarks:

inspected on 29 and 30 November 2010 / signed on 11 April 2011

Type of method:

dynamic method

Key result

Decomposition:

ambiguous

Remarks on result:

other: No defined boiling point of the test item could be determined using dynamic method.

Two experiments were performed using the dynamic method and the following observations were made:

 

Boiling in the vessel and formation of a colourless condensate were observed at a sample temperature of approx. 130 °C. This might be due to higher volatile components of the test item or to decomposition of the substance. However, the Cottrell pump didn’t pump. No boiling indicated by pumping Cottrell pump was observed up to 203 °C (first determination, at 100156 Pa) resp. 220.8 °C (second determination, at 99579 Pa) while the temperature measured in the sample was 360 °C (first determination) resp. 380 °C (second determination).

The thermometer in the Cottrell pump showed a much lower temperature than the temperature in the sample. If a liquid boils, the measured temperatures of the thermometers should be similar. Therefore, the temperature difference between the thermometers is considered as a sign of decomposition. The change in appearance and odour of the test item after cooling down are additional signs of decomposition of the test item during the experiment.

Finally no initial boiling point of the test item could be determined using the dynamic method andinitial temperature of decomposition of the test item is not clearly determined.

No observations were made which might cause doubts on the validity of the study outcome. Therefore, the result of the study is considered valid.

Conclusions:

No clear initial boiling point of the test item could be determined using the dynamic method. In addition, signs of decomposition were observed when the substance is heated up to 380°C.

Executive summary:

A study was conduted to determine the initial boiling point of the test substance under GLP according to EU Method A.2 and OECD 103 following the dynamic method.

Two experiments were conducted but no clear initial boiling point of the test item could be determined using this method. In addition, signs of decomposition were observed when the substance is heated up to 380°C : a colourless condensate observed at a sample temperature of approximately 130°C might be due to the higher volatile components of the test item (minor part of the substance) or to the decomposition of the subtance. In addition, a significant difference was observed between the sample temperature and the temperature of the Cottrell pump when a boiling is detected. Finally after cooling down, the test item appeared deep black and the odour had changed to burned sugar, which indicated decomposition during the experiment.

Description of key information

No clear initial boiling point of the test item could be determined using the dynamic method.

In addition, signs of decomposition were observed when the substance is heated up to 380°C.

Additional information

A reliable experimental study, conducted according to a recognized OECD/EC, following the dynamic method and under GLP, is available. It is considered as a key study. However, no clear initial boiling point or initial decomposition temperature could be determined using the dynamic method. Considering the complex nature of the substance, no key value is retained for this endpoint.