Strontium neodecanoate

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2015-04-26 to 2015-04-29

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

yes

Remarks:

two vessels were set up in a parallel design at 20 ± 1.0 °C, each vessel was sampled several times instead of sampling one vessel at every point in time

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

yes

Remarks:

two vessels were set up in a parallel design at 20 ± 1.0 °C, each vessel was sampled several times instead of sampling one vessel at every point in time

GLP compliance:

yes (incl. QA statement)

Remarks:

signed 2011-02-07

Type of method:

flask method

Specific details on test material used for the study:

- Storage condition of test material: Ambient temperature, keep container tightly closed, store dry

Water solubility:

45.074 g/L

Temp.:

20 °C

pH:

>= 8.3 - <= 8.5

Remarks on result:

other: SD: 2.863 g/L

Details on results:

Observations
During the study, undissolved test material was observed. Swelling and agglutination of the test substance in ultrapure water was observed. After filtration, the solution was clear. In order to verify this, the turbidity was measured in the filtered samples.

Temperature
The temperature in the thermostatically controlled water bath was monitored by a thermo data logger (Testo 175-T2, Testo AG, Leutkirch, Germany). The mean temperature was 20.6 ± 0.2 °C.

Monitoring oxygen amount
During the experimental performance of the test, the amount of oxygen within the acrylic glass box was monitored with a MICRO IV oxygen sensor prior and after sampling. The displayed oxygen values (in %) were always at about 0 %.

pH values
The pH in test item loaded vessels was in the range of 8.3 – 8.5, whereas the pH in method blanks ranged from 6.6 – 6.8. Solution pH was measured directly
in the test vessel using an inoLab 9430 equipped with SenTix 940-3 (pH) electrodes from WTW (Weilheim, Germany). Measurements were taken after readings had stabilized and waiting for an additional minute. Two electrodes were used to exclude cross contaminations:
One for the method blanks and the other one only for the solutions in the test item loaded vessels. A calibration of the pH meter was performed every workweek and the device was verified every working day with commercially available certified pH buffer solutions (pH 9.21, lot no. 1Z196D, expiry date 2016-07-15; pH 7.00, lot no. 1Z204I, expiry date 2016-07-23; pH 4.01, lot no. 1Z205F, expiry date 2016.07-25; pH 2.00, lot no. 1Z244F, expiry date 2016-09-01; all obtained from Mettler Toledo, Urdorf, Switzerland).

Turbidity
The turbidity was measured after filtration to verify that only dissolved strontium concentrations would get measured. The turbidity was always <1 NTU, indicating that no undissolved material was left after the filtration step.

ICP-OES measurement
Strontium levels of method blanks were always below the limit of detection (LOD: 3.25 – 6.47 μg Sr/L). Test samples were analysed within one day after sampling.

Method validation summary

validation parameter	results	comment
selectivity	Strontium detected and evaluated at a wavelength of 215.284 nm	no matrix effects observed
linearity	applied calibration functions were linear	correlation coefficient at least 0.999981
limits of detection(LOD)	3.25 – 6.47 μg Sr/L
limits of quantification (LOQ)	10.8 – 21.6 μg Sr/L
method blanks	below limits of detection
accuracy and precision, reproducibility	mean recovery for CRM TM-25.4: 98.8 ± 1.7 % (n = 5)	corresponds to very low concentration range (73.4 μg Sr/L)
accuracy and precision, reproducibility	mean recovery for CRM TM-53.3:98.7 ± 0.6 % (n = 5)	corresponds to concentration range of diluted samples (369 μg Sr/L)
accuracy and precision, reproducibility	mean recovery for Multi Element Standard XXI: 100 ± 1 % (n = 5)	corresponds to higher concentration range of diluted samples (500 μg Sr/L)
accuracy and precision, reproducibility	mean recovery for recalibration standard: 97.2 ± 0.9 % (n = 5)	corresponds to higher concentration range of diluted samples (500 μg Sr/L)
trueness	recovery from fortification of samples: 98.2 – 101 % (n = 6)

Constant strontium concentrations according to the study guideline OECD 105 as well as the Regulation 440/2008/EC A.6 were measured during the study from day 1 to day 3. Therefore, the water solubility of the test item is calculated by the Sr concentrations of all samples from day 1 – day 3:

Calculation of the water solubility of test item

	Mean Sr conc. d1 - d3 [g/L]	SD Sr conc. d1-d3 [g/L]	content ofSr in test item[%]	Mean calculatedsolved test item d1-d3 [g/L]	SD calculatedsolved test item d1-d3 [g/L]
vessel 1	8.606	0.381	18.8	45.777	2.025
vessel 2	8.342	0.671	18.8	44.372	3.571
all samples	8.474	0.538	18.8	45.074	2.863

Under the conditions of this test (under exclusion of CO2 and O2, under inert argon gas; flask method; loadings of 200.009 g/L and 200.020 g/L in vessel 1 and 2), a solubility equilibrium was observed during the testing (days 1 – 3). The mean amount of dissolved strontium, during the test at 20.0 ± 1.0°C is 8.47 ± 0.54 g Sr/L (determined as dissolved strontium, separated by filtration from undissolved test item; standard deviation is calculated from all samples days 1 - 3). This corresponds to calculated dissolved strontium neodecanoate of 45.07 ± 2.86 g/L. The pH in test item loaded vessels was in the range of 8.3 – 8.5, whereas the pH in method blanks ranged from 6.6 – 6.8

Conclusions:

Interpretation of results: very soluble (> 10000 mg/L)
Under the conditions of this test (under exclusion of CO2 and O2, under inert argon gas; flask method; loadings of 200.009 g/L and 200.020 g/L in vessel 1 and 2), a solubility equilibrium was observed during the testing (days 1 – 3). The mean amount of dissolved strontium, during the test at 20.0 ± 1.0 °C is 8.47 ± 0.54 g Sr/L (determined as dissolved strontium, separated by filtration from undissolved test item; standard deviation is calculated from all samples days 1 - 3). This corresponds to calculated dissolved strontium neodecanoate of 45.07 ± 2.86 g/L.

Description of key information

Strontium neodecanoate has a water solubility of 45.07 ± 2.86 g/L at 20.0 ± 1.0 °C.

Key value for chemical safety assessment

Water solubility:

45.07 g/L

at the temperature of:

20 °C

Additional information

Under the following conditions (exclusion of CO₂ and O₂, inert argon gas; flask method; loadings of 200.009 g/L and 200.020 g/L), a solubility equilibrium was observed during the testing (days 1 – 3). The mean amount of dissolved strontium, during the test at 20.0 ± 1.0 °C is 8.47 ± 0.54 g Sr/L (determined as dissolved strontium, separated by filtration from undissolved test item; standard deviation is calculated from all samples days 1 - 3). This corresponds to calculated dissolved strontium neodecanoate of 45.07 ± 2.86 g/L.