Glycine hydrochloride

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2019-03-29 to 2019-04-05

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Key result

Water solubility:

825.32 g/L

Conc. based on:

test mat.

Loading of aqueous phase:

2 500 g/L

Incubation duration:

72 h

Temp.:

20 °C

pH:

1

Details on results:

A mean concentration of 825.32 g/L with standard deviation of 25.69 g/L was calculated, giving a relative standard deviation of 3.1 %.

Measurements during Equilibration

The data which was acquired during equilibration time (flask 1A-C, days 1 – 3) is presented in the following table:

 

Day	Temperature [°C]	pH*	Peak Area [mV*min]	Measured values [mg/L]	Concentration test item [g/L]	Difference to previous sample
1	20.0	~1	14.3871	0.310	775.3	-
2	20.0	~1	14.0717	0.303	758.3	-2.2%
3	20.0	~1	14.5778	0.314	785.5	3.6%

 

Measurements at Plateau

The concentrations of the test item were determined from the measured values. 

Flask No.	Temperature [°C]	pH*	Peak Area [mV*min]	Concentration (diluted sample) [g/L]	Dilution factor	Concentration (original sample) [g/L]
1C	20.0	~1	14.5778	0.314	2.5 * 10^6	785.5
2	20.0	-0.35	15.1346	0.326	2.5 * 10^6	815.5
3	20.0	-0.31	15.7698	0.340	2.5 * 10^6	849.6
4	20.0	-0.35	15.6442	0.337	2.5 * 10^6	842.9
5	20.5	-0.33	46.4215	0.999	2.5 * 10^6	2498.0
6	20.5	-0.34	15.4624	0.333	2.5 * 10^6	833.1

Values in italics: Outlier, dilution error; was not used for evaluation

Temperature was measured with 20.0 – 20.5 °C in flasks 1C – 6.

 

Day	Flask	Concentration [g/L]	Total Mean [g/L]	Total Standard Deviation [g/L] (RSD* [%])
1	1A	775.3
2	1B	758.3
3	1C	785.5	825.32	25.69 (3.1)
3	2	815.5
3	3	849.6
3	4	842.9
3	6	833.1
3	5	2498.0

 

A mean concentration of 825.32 g/L with standard deviation of 25.69 g/L was calculated, giving a relative standard deviation of 3.1 %.

Conclusions:

The water solubility of the test item was determined to be 825.3 g/L at 20 °C.

Executive summary:

The water solubility was determined according to OECD 105 using the shake flask method with HPLC analysis. The solubility of the test item was determined by measurement of the test item concentration in the filtrated test solutions using HPLC/FLD (fluorescence light detection) after automated sample preparation are performed until equilibrium is reached. In the pre-test, the test tube with nominal concentrations of 200 – 1000 g/L appeared clear. The solubility was expected to lie above 10 mg/L, therefore the flask method was used according to the guideline. 2500 g/L nominal concentration was chosen. Three flasks were used during equilibration and five flasks for the determination at the plateau. Seven flasks were set onto the shaking apparatus immediately. After 24 h and after 48 h, flask were set on the shaker and all flasks were shaken for further 24 h at room temperature (20.0 ± 0.5 °C). Then, flasks were taken from the shaker, samples were taken, membrane filtrated with a nylon filter and analysed. No rising tendency in the test item concentration of the solutions was found on day 3. No Tyndall effect (i.e. a laser beam was not scattered when transmitted through the liquid) could be observed indicating that no colloidal dispersed particles or micelles were present. The pH of each sample was recorded. The water solubility of the test substance was determined to be 825.3 ± 25.7 g/L (95 % confidence interval) at 20 °C ± 1 °C and 1).

Description of key information

The water solubility of the test item was determined to be 825.3 g/L at 20 °C.

Key value for chemical safety assessment

Water solubility:

825.3 g/L

at the temperature of:

20 °C

Additional information

The water solubility was determined according to OECD 105 using the shake flask method with HPLC analysis (reference 4.8-1). The solubility of the test item was determined by measurement of the test item concentration in the filtrated test solutions using HPLC/FLD (fluorescence light detection) after automated sample preparation are performed until equilibrium is reached. In the pre-test, the test tube with nominal concentrations of 200 – 1000 g/L appeared clear. The solubility was expected to lie above 10 mg/L, therefore the flask method was used according to the guideline. 2500 g/L nominal concentration was chosen. Three flasks were used during equilibration and five flasks for the determination at the plat-eau. Seven flasks were set onto the shaking apparatus immediately. After 24 h and after 48 h, flask were set on the shaker and all flasks were shaken for further 24 h at room temperature (20.0 ± 0.5 °C). Then, flasks were taken from the shaker, samples were taken, membrane filtrated with a nylon filter and analysed. No rising tendency in the test item concentration of the solutions was found on day 3. No Tyndall effect (i.e. a laser beam was not scattered when transmitted through the liquid) could be observed indicating that no colloidal dispersed particles or micelles were present. The pH of each sample was recorded. The water solubility of the test substance was determined to be 825.3 ± 25.7 g/L (95 % confidence interval) at 20 °C ± 1 °C and 1).