Saccharomyces cerevisiae, lysate

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 08 May to May 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

GLP study

Qualifier:

according to guideline

Guideline:

EU Method A.4 (Vapour Pressure)

Version / remarks:

EC No. 761/2009

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

Version / remarks:

March 23, 2006

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

effusion method: isothermal thermogravimetry

Key result

Test no.:

#1

Temp.:

>= 120 °C

Vapour pressure:

0.046 Pa

The evaporation rate of the test item (VT) is calculated from the weight loss of the test item at  defined temperatures in a constant stream of nitrogen over periods of time. Linear regression analysis of log VT versus 1/T (1000/T) is performed for the test item and for each reference item. The evaporation rates at 20 °C (VT, 20) are determined from these relationships. The relationship between the values of VT, 20 of the reference items and their known vapour pressures is established as a regression equation. The relationship between evaporation rate and vapour pressure, derived for 20 °C, includes the characteristics of the experimental setup, which are subsequently employed in the calculation of vapour pressure values at other temperatures.

Evaporation rate : VT = ∆m / F x t

VT= evaporation rate [g x cm(-2) xh(-1)]

∆m = weight loss of the test item [g]

F = surface of the sample plate [cm2]

t = elapsed time for the weight loss [h]

Based on the determined evaporation rates the evaporation rate curve is established for each of the reference items as well as for the test item. The evaporation rates at 20 °C  are extrapolated from the curves.

Evaporation rate curve : log Vt = a x 1000/T + b

With a = -2.8731 and b = 3.9806 (R2 = 0.9939)

The evaporation rates at VT 20 °C of the reference items are used to establish a regression line of log PT versus log VT, which characterizes the specific experimental setup. From this regression equation the vapour pressure PT of the test item as a function of temperature is calculated based on the determined evaporation rate.

log Pt = C + D x log Vt

Pt = vapour pressure [Pa]

VT = evaporation rate [g x cm(-2) x h(-1)]

C, D = intercept and slope as constants specific for experimental set up determined from regression curve

C = 4.3781 and D = 1.0022  (R2 = 0.9825)

Inserting the equation for log VT above, the following equation for the temperature dependence of the vapour pressure of the test item is obtained : log Pt = C + D x (a x 1000/T + b)

(where: a = -2.8371, b = 3.9806, C = 4.3781 and D = 1.0022)

With this equation, the following vapour pressure results were obtained:  4.60 x 10-2 Pa at 20 °C.

Conclusions:

The vapour pressure of Saccharomyces cerevisiae lysate is 0.046 Pa at 20°C.

Executive summary:

The vapour pressure of Saccharomyces cerevisiae lysate was determined according to the EU method A.4 and OECD 104 and in compliance with GLP.

The effusion method based on the Isothermal Thermogravimetry was used. The evaporation rates of the test item between 120 °C and 160 °C at ambient pressure and in a constant stream of nitrogen were determined by monitoring the weight loss over the time. These measurements were also performed for the reference substances. The evaporation rates at 20 °C (VT20) were determined and the relationship between the values VT20 of the reference items and their known vapour pressures are used to calculate the vapor pressure of the test item at 20°C.

The vapour pressure of the test item was calculated (mean of three determinations) to be 4.60 x 10-2 Pa at 20 °C.

The vapour pressure study is classified as acceptable, and satisfies the guideline requirements of the EU method A.4 and OECD 104.

Description of key information

The vapour pressure of Saccharomyces cerevisiae lysate was determined to be is 4.60 x 10-2 Pa at 20 °C.

Key value for chemical safety assessment

Vapour pressure:

0.046 Pa

at the temperature of:

20 °C

Additional information

The vapour pressure of Saccharomyces cerevisiae lysate was determined according to the EU method A.4 and OECD 104 and in compliance with GLP.

The effusion method based on the Isothermal Thermogravimetry was used. The evaporation rates of the test item between 120 °C and 160 °C at ambient pressure and in a constant stream of nitrogen were determined by monitoring the weight loss over the time. These measurements were also performed for the reference substances. The evaporation rates at 20 °C (VT20) were determined and the relationship between the values VT20 of the reference items and their known vapour pressures are used to calculate the vapor pressure of the test item at 20°C.

The vapour pressure of the test item was calculated (mean of three determinations) to be 4.60 x 10-2 Pa at 20 °C.