Extract obtained from the shell of Theobroma cacao (Malvaceae) by co-extraction with ethanol and propylene glycol

Melting point / freezing point

Administrative data

Endpoint:

melting point/freezing point

Remarks:

Modulated DSC

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

other: internal determination

Title:

Unnamed

Year:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: Modulated DSC SOP

Version / remarks:

see attached details

Deviations:

no

Principles of method if other than guideline:

The theory supporting modulated DSC can be easily understood by comparing it to conventional DSC. In conventional DSC, the difference in heat flow between a sample and an inert reference is measured as a function of time and temperature as both the sample and reference are subjected to a controlled environment of time, temperature, and pressure. The most common instrument design for making those DSC measurements is the heat flux design shown in Figure 1. In this design, a metallic disk (made of constantan alloy) is the primary means of heat transfer to and from the sample and reference. The sample, contained in a metal pan, and the reference (an empty pan) sit on raised platforms formed in the constantan disc. As heat is transferred through the disc, the differential heat flow to the sample and reference is measured by area thermocouples formed by the junction of the constantan disc and CHROMEL®* wafers which cover the underside of the platforms. These thermocouples are connected in series and measure the differential heat flow using the thermal equivalent of Ohm’s Law, , where = heat flow, ∆T = the temperature difference between reference and sample and RD = the thermal resistance of the constantan disc. CHROMEL®* and ALUMEL®* wires attached to the CHROMEL®* wafers form thermocouples which directly measure sample temperature. Purge gas is admitted to the sample chamber through an orifice in the heating block before entering the sample chamber. The result is a uniform, stable thermal environment which assures better baseline flatness and sensitivity (signal-to-noise) than alternative DSC designs. In conventional DSC, the temperature regime seen by the sample and reference is linear heating or cooling at rates from as fast as 100°C/minute to rates as slow as 0°C/minute (isothermal).
Modulated DSC is a technique which also measures the difference in heat flow between a sample and an inert reference as a function of time and temperature. In addition, the same “heat flux” cell design is used. However, in MDSC a different heating profile (temperature regime) is applied to the sample and reference. Specifically, a sinusoidal modulation (oscillation) is overlaid on the conventional linear heating or cooling ramp to yield a profile in which the average sample temperature continuously changes with time but not in a linear fashion. The solid line in Figure 2 shows the profile for a MDSC heating experiment. The net effect of imposing this more complex heating profile on the sample is the same as if two experiments were run simultaneously on the material - one experiment at the traditional linear (average) heating rate [dashed line in Figure 2] and one at a sinusoidal (instantaneous) heating rate [dashed-dot line in Figure 2]. The actual rates for these two simultaneous experiments is dependent on three operator-selectable variables:

GLP compliance:

no

Other quality assurance:

other: according to instruction guidelines

Type of method:

differential scanning calorimetry

Test material

Test material information

Constituent 1

Reference substance name:

Extract obtained from the shell of Theobroma cacao (Malvaceae) by co-extraction with ethanol and propylene glycol

EC Number:

948-055-8

Molecular formula:

not applicable as it is a UVCB

IUPAC Name:

Extract obtained from the shell of Theobroma cacao (Malvaceae) by co-extraction with ethanol and propylene glycol

Test material form:

liquid: viscous

Details on test material:

- Physical appearance: dark brown to black viscous liquid
- Storage conditions: in refrigerator (2-8°C) protected from light

Results and discussion

Melting / freezing point

Key result

Melting / freezing pt.:

-74 °C

Decomposition:

no

Sublimation:

no

Applicant's summary and conclusion

Executive summary:

Freezing/melting point accurately determined