Glycine hydrochloride

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 2017-08-28 to 2017-09-15

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.4 (Vapour Pressure)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

effusion method: Knudsen cell

Key result

Temp.:

20 °C

Vapour pressure:

0.003 Pa

Temp.:

25 °C

Vapour pressure:

0.005 Pa

Observations

60°C: At the first measurement of experiment 3, all cells were slightly contaminated. Therefore, the cells were meticulously cleaned and weighed. This weight was used as initial weight for the subsequent measurements. To avoid bias, this measurement was not used for calculations.

75°C: At the third measurement of experiment 4, all cells were slightly contaminated. Therefore, the cells were meticulously cleaned and weighed. This weight was used as initial weight for the subsequent measurements. To avoid bias, this measurement was not used for calculations.

Calculation results

The calculation results of experiment 2-4 (nominal temperature 45, 60 and 75°C) are given in the tables below and on the following pages. The calculation results of experiment 1 and 5 are no reproducible results, therefore the results are not showed.

Table 2: Calculation results experiment 2

Experiment	2
Real Temperature in K	318.2
Real Temperature in °C	45.0
Date of Measurement	01.09.2017 07:55					02.09.2017 07:15			03.09.2017 12:46
Elapsed Time in s	73200					81000			102360
Parameter	Weight loss	to be used		Vapour pressure		Weight loss	to be used	Vapour pressure	Weight loss	to be used	Vapour pressure
Unit	g	yes/no		Pa		g	yes/no	Pa	g	yes/no	Pa
Knudsen-cell 1	0.00270	yes		1.99E-02		0.00337	yes	2.25E-02	0.00381	yes	2.01E-02
Knudsen-cell 2	0.00234	yes		1.73E-02		0.00291	yes	1.94E-02	0.00362	yes	1.91E-02
Knudsen-cell 3	0.00237	yes		1.75E-02		0.00293	yes	1.96E-02	0.00364	yes	1.92E-02
Knudsen-cell 4	0.00271	yes		2.00E-02		0.00358	yes	2.39E-02	0.00412	yes	2.18E-02
Mean		yes		1.87E-02			yes	2.13E-02		yes	2.01E-02
Standard deviation:				1.50E-03				2.22E-03			1.22E-03
Mean of measured values:				2.003E-02
Standard deviation:				1.328E-03		RSD:	6.6%

Table 3: Calculation result experiment 3

Experiment

3

Real Temperature in K

333.2

Real Temperature in °C

60.0

Date of Measurement

04.09.2017 11:45

05.09.2017 09:15

*

06.09.2017 11:50

Elapsed Time in s

78900

73200

To be corrected

84900

Parameter

Weight loss

to be used

Vapour pressure

Weight loss

to be used

Vapour pressure

Weight loss

to be used

Vapour pressure

Weight loss

to be used

Vapour pressure

Unit

g

yes/no

Pa

g

yes/no

Pa

g

yes/no

Pa

g

yes/no

Pa

Knudsen-cell 1

0.02468

yes

1.73E-01

0.00707

yes

5.34E-02

0.05090

no

-

0.00510

yes

3.32E-02

Knudsen-cell 2

0.02269

yes

1.59E-01

0.00624

yes

4.72E-02

0.03582

no

-

0.00623

yes

4.06E-02

Knudsen-cell 3

0.02352

yes

1.65E-01

0.00673

yes

5.09E-02

0.03982

no

-

0.00667

yes

4.35E-02

Knudsen-cell 4

0.02553

yes

1.79E-01

0.00692

yes

5.23E-02

0.05448

no

-

0.00494

yes

3.22E-02

Mean

no

yes

5.10E-02

no

yes

3.74E-02

Standard deviation:

2.73E-03

5.52E-03

Mean of measured values:

4.417E-02

Standard deviation:

9.597E-03

RSD:

21.7%

*The cells were weighed, because the sensor of the thermometer was broken.

If “no” is stated in the respective column: measurement was not considered for the calculation of the mean.

Table 4: Calculation results experiment 4

Experiment	4
Real Temperature in K	348.2
Real Temperature in °C	75.0
Date of Measurement	07.09.2017 09:30					08.09.2017 08:10			12.09.2017 12:05
Elapsed Time in s	75000					78900			77700
Parameter	Weight loss	to be used		Vapour pressure		Weight loss	to be used	Vapour pressure	Weight loss	to be used	Vapour pressure
Unit	g	yes/no		Pa		g	yes/no	Pa	g	yes/no	Pa
Knudsen-cell 1	0.01645	yes		1.24E-01		0.01472	yes	1.06E-01	0.00782	no	5.69E-02
Knudsen-cell 2	0.01820	yes		1.37E-01		0.01474	yes	1.06E-01	0.00964	no	7.02E-02
Knudsen-cell 3	0.02004	yes		1.51E-01		0.01584	yes	1.14E-01	0.00997	no	7.26E-02
Knudsen-cell 4	0.01672	yes		1.26E-01		0.01436	yes	1.03E-01	0.00795	no	5.79E-02
Mean		yes		1.35E-01			yes	1.07E-01		no
Standard deviation:				1.24E-02				4.60E-03
Mean of measured values:				1.208E-01
Standard deviation:				1.960E-02		RSD:	16.2%

If “no” is stated in the respective column: measurement was not considered for the calculation of the mean.

Table 5: Evaluation of calculated values

Parameter	T	Mean p	1/T	log p
Unit	K	Pa	1/K	log Pa
Values	318.2	2.00E-02	3.1427E-03	-1.6983
	333.2	4.42E-02	3.0012E-03	-1.3549
	348.2	1.21E-01	2.8719E-03	-0.9180

Table 6: Parameters of linear regression

Parameter	Value
Slope	-2874.7
Intercept	7.3155
Correlation Coefficient r	-0.9955
Coefficient of Determination r^2	0.9910

The following vapour pressures were determined experimentally and considered as valid (mean and standard deviation given):

Table 7: Experimentally determined vapour pressures

T	T	p	Stand. Dev. p	RSD p
°C	K	Pa	Pa	%
45.0	318.2	2.00E-02	1.33E-03	6.6%
60.0	333.2	4.42E-02	9.60E-03	21.7%
75.0	348.2	1.21E-01	1.96E-02	16.2%

The linear regression of log P vs. 1/T gave a correlation coefficient r of -0.9955, showing good repeatability and precision. Therefore, the determination is considered as valid.

Table 8: Positive control

Vapour pressure (positive control) at 30°C:	1.53 * 10^-1Pa
Criteria for the vapour pressure of the positive control at 30°C	1.44 * 10^-1± 0.1 Pa

Conclusions:

The vapour pressure of the test item was determined by extrapolation of the measured vapour pressures for the temperatures 20 and 25 °C:
- 3.23E-3 Pa at 20 °C
- 4.72E-3 Pa at 25 °C

Executive summary:

A study was performed according to OECD TG 104 and Commission Regulation (EC) No. 761/2009, method A.4 in order to determine the vapour pressure of the test item by effusion method (Knudsen cell).

The vapour pressure of the test item was determined at five different temperatures (30, 45, 60, 75 and 90 °C). Experiment 1 and 5 (nominal temperature 30 and 90 °C) showed no reproducible weight loss and were excluded from the further calculation. Finally, three experiments (45, 60 and 75 °C) could be evaluated and were used for extrapolation of the vapour pressures at 20 °C and 25 °C by linear regression curve. The vapour pressure of the test item was determined to be 3.23 * 10^-3 Pa at 20 °C and 4.72 * 10^-3 Pa at 25 °C.

Description of key information

The vapour pressure of the test item was determined by extrapolation by means of the measured vapour pressures for the temperatures 20 and 25 °C:

- 3.23 * 10^-3 Pa at 20 °C

- 4.72 * 10^-3 Pa at 25 °C

Key value for chemical safety assessment

Vapour pressure:

0.003 Pa

at the temperature of:

20 °C

Additional information

A study was performed according to OECD TG 104 and Commission Regulation (EC) No. 761/2009, method A.4 in order to determine the vapour pressure of the test item by effusion method (Knudsen cell).

The vapour pressure of the test item was determined at five different temperatures (30, 45, 60, 75 and 90 °C). Experiment 1 and 5 (nominal temperature 30 and 90 °C) showed no reproducible weight loss and were excluded from the further calculation. Finally, three experiments (45, 60 and 75 °C) could be evaluated and were used for extrapolation of the vapour pressures at 20 °C and 25 °C by linear regression curve. The vapour pressure of the test item was determined to be 3.23 * 10^-3 Pa at 20 °C and 4.72 * 10^-3 Pa at 25 °C (reference 4.6-1).