Cadmium selenide

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

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:

see "Details on methods" for details.

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Remarks:

Limit test

Key result

Water solubility:

5.7 µg/L

Conc. based on:

other: Cadmium

Temp.:

20 °C

pH:

>= 7.2 - <= 7.5

Details on results:

Preliminary test
Precipitation was observed which was independent from sample weight, measurements showed fluctuations.
It was thought that the fluctuations could be caused by (maybe inhomogeneous) impurities. Therefore following confirmation with the sponsor it was decided that it makes more sense to carry out the main test with different loading rates at one temperature (20 ° C).

Main test
The results of the solubility of "Cadmium selenide" in water with different loading rates at 20 °C.
The temperatures of the water baths were between 19.9 and 20.0 °C.
The pH of the solutions was 7.2 to 7.5 at both loading rates.

The solubilities showed constancy (criteria for constancy is a change of concentration of < 15 % compared with the day before) from the first sampling day (after 21 days of stirring) and was stopped after 23 days of stirring.

For calculation of the results all results were taken. The following results were obtained at the different loading rates:
100 mg test item / L: Solubility = < 5.7 µg test item / L
1000 mg test item / L: Solubility = < 5.7 µg test item / L

The replicates per loading rate were comparable. All results are lower than the limit of quantification.

Water solubility with an initial loading rate of 100 mg test item / L

Equilibration time	Loading rate 100 mg test item / L: Concentration of dissolved µg Cd / L
	1^streplicate	2^ndreplicate	3^rdreplicate	Mean
Day 21	< 3.3	< 3.3	< 3.3	< 3.3
Day 22	< 3.3	< 3.3	< 3.3	< 3.3
Day 23	< 3.3	< 3.3	< 3.3	< 3.3
Overall mean				< 3.3
Overall standard deviation				***

 

Equilibration time	Loading rate 100 mg test item / L: Concentration in µg test item / L
	1^streplicate	2^ndreplicate	3^rdreplicate	Mean
Day 21	< 5.7	< 5.7	< 5.7	< 5.7
Day 22	< 5.7	< 5.7	< 5.7	< 5.7
Day 23	< 5.7	< 5.7	< 5.7	< 5.7
Overall mean				< 5.7
Overall standard deviation				***

 

Equilibration time	Loading rate 100 mg test item / L: pH
	1^streplicate	2^ndreplicate	3^rdreplicate	Mean
Day 21	7.26	7.29	7.42	7.32
Day 22	7.29	7.18	7.33	7.27
Day 23	7.38	7.22	7.41	7.34
Overall mean				7.31
Overall standard deviation				0.04

 

Water solubility with an initial loading rate of 1000 mg test item / L

Equilibration time	Loading rate 1000 mg test item / L: Concentration of dissolved µg Cd / L
	1^streplicate	2^ndreplicate	3^rdreplicate	Mean
Day 21	< 3.3	< 3.3	< 3.3	< 3.3
Day 22	< 3.3	< 3.3	< 3.3	< 3.3
Day 23	< 3.3	< 3.3	< 3.3	< 3.3
Overall mean				< 3.3
Overall standard deviation				***

 

Equilibration time	Loading rate 1000 mg test item / L: Concentration in µg test item / L^*)
	1^streplicate	2^ndreplicate	3^rdreplicate	Mean
Day 21	< 5.7	< 5.7	< 5.7	< 5.7
Day 22	< 5.7	< 5.7	< 5.7	< 5.7
Day 23	< 5.7	< 5.7	< 5.7	< 5.7
Overall mean				< 5.7
Overall standard deviation				***

 

Equilibration time	Loading rate 1000 mg test item / L: pH
	1^streplicate	2^ndreplicate	3^rdreplicate	Mean
Day 21	7.38	7.24	7.40	7.34
Day 22	7.29	7.31	7.30	7.30
Day 23	7.36	7.38	7.51	7.42
Overall mean				7.35
Overall standard deviation				0.06

 

Analytical method:    

A method was validated to determine the content of cadmium in water to calculate the water solubility of the test item “Cadmium selenide”.

Linearity:	The calibration curve was linear from the quantification limit up to the highest concentration of 100 µg Cd / L.
Detection limit:	0.19 µg Cd / L
Quantification limit:	0.66 µg Cd / L
Residual standard deviation:	24 cps
Method standard deviation:	0.24 µg Cd / L
Relative method standard deviation:	0.62 %

Detection limit

0.19 µg Cd / L in the diluted samples, which corresponds to 1.7 µg test item / L calculated with a dilution factor of 5 (rounded up to two significant digits).

Quantification limit

0.66 µg Cd / L in the diluted samples, which corresponds to 5.7 µg test item / L calculated with a dilution factor of 5 (rounded up to two significant digits).

Residual standard deviation

The residual standard deviation was 24 counts per second (cps) in the diluted samples.

 

Detection limit

0.19 µg Cd / L in the diluted samples, which corresponds to 1.7 µg test item / L calculated with a dilution factor of 5 (rounded up to two significant digits).

Quantification limit

0.66 µg Cd / L in the diluted samples, which corresponds to 5.7 µg test item / L calculated with a dilution factor of 5 (rounded up to two significant digits).

Residual standard deviation

The residual standard deviation was 24 counts per second (cps) in the diluted samples.

Method standard deviation

The method standard deviation was 0.24 µg Cd / L in the diluted samples.

 

Relative method standard deviation

The relative method standard deviation was 0.62 %.

Accuracy

Sample	Measured concentration without addition (µg Cd / L)	Added concentration calculated (µg Cd / L)	Measured concentration with addition (µg Cd / L)	Added concentration measured (µg Cd / L)	Recovery (%)
Measurement 1	0*	10	10.110	10.110	101
Measurement 2	0*	10	10.270	10.270	103
Measurement 3	0*	10	10.380	10.380	104
				Mean:	103

* As the measured concentration of the samples without addition was below the quantification limit, as value of 0 was used for the calculation of the recovery.

The mean recovery of the standard addition experiment was 103 %.

Specificity/ Selectivity

The specificity of the element cadmium was proved by using two different wavelengths which are characteristic and specific for cadmium. The specificity was calculated from the measurements of the spiked samples from the accuracy experiments.

Sample	Measured concentration (µg Cd / L)
	214.400 nm	228.802 nm
Measurement 1	10.110	10.400
Measurement 2	10.270	10.290
Measurement 3	10.380	10.420
Mean	10.253	10.370

The deviation between the two wavelengths was lower than 3 % relative and prove the specificity of the used wavelengths.

Repeatability/ Reproducibility

Sample	Intensity [counts / s]						RSD
	1	2	3	4	5	6	[%]
Level 1	634.658	638.337	640.563	644.510	643.214	638.246	0.6
Level 2	1124.435	1136.065	1127.236	1131.720	1124.749	1128.226	0.4
Level 3	2645.805	2661.940	2652.675	2663.526	2644.614	2645.773	0.3
Level 4	5056.573	5124.987	5116.134	5102.950	5095.017	5113.846	0.5
Level 5	7572.560	7608.715	7623.466	7611.561	7587.270	7576.395	0.3
Level 6	10120.095	10100.092	10023.629	10123.583	10144.631	10104.785	0.4

The relative standard deviations (RSD) lower than 5 % of the different levels prove the precision of the analysis.

The method standard deviation was 0.24 µg Cd / L in the diluted samples.

 

Relative method standard deviation

The relative method standard deviation was 0.62 %.

 

Accuracy

Sample	Measured concentration without addition (µg Cd / L)	Added concentration calculated (µg Cd / L)	Measured concentration with addition (µg Cd / L)	Added concentration measured (µg Cd / L)	Recovery (%)
Measurement 1	0*	10	10.110	10.110	101
Measurement 2	0*	10	10.270	10.270	103
Measurement 3	0*	10	10.380	10.380	104
				Mean:	103

* As the measured concentration of the samples without addition was below the quantification limit, as value of 0 was used for the calculation of the recovery.

The mean recovery of the standard addition experiment was 103 %.

Specificity/ Selectivity

The specificity of the element cadmium was proved by using two different wavelengths which are characteristic and specific for cadmium. The specificity was calculated from the measurements of the spiked samples from the accuracy experiments.

 

Sample	Measured concentration (µg Cd / L)
	214.400 nm	228.802 nm
Measurement 1	10.110	10.400
Measurement 2	10.270	10.290
Measurement 3	10.380	10.420
Mean	10.253	10.370

The deviation between the two wavelengths was lower than 3 % relative and prove the specificity of the used wavelengths.

Repeatability/ Reproducibility

Sample	Intensity [counts / s]						RSD
	1	2	3	4	5	6	[%]
Level 1	634.658	638.337	640.563	644.510	643.214	638.246	0.6
Level 2	1124.435	1136.065	1127.236	1131.720	1124.749	1128.226	0.4
Level 3	2645.805	2661.940	2652.675	2663.526	2644.614	2645.773	0.3
Level 4	5056.573	5124.987	5116.134	5102.950	5095.017	5113.846	0.5
Level 5	7572.560	7608.715	7623.466	7611.561	7587.270	7576.395	0.3
Level 6	10120.095	10100.092	10023.629	10123.583	10144.631	10104.785	0.4

The relative standard deviations (RSD) lower than 5 % of the different levels prove the precision of the analysis.

Conclusions:

The objective of the study was to determine the water solubility of the test substance "Cadmium selenide". For the complete test substance no single analytical method is available. The water solubility was determined using the flask method and estimated by analysis of the element cadmium using Inductively coupled plasma – atomic emission spectroscopy (ICP-AES).
Preliminary tests and measurements showed fluctuations at room temperature. Therefore it was decided with the sponsor to take different loading rates at 20 ° C rather than to determine the water solubility at different temperatures.
Mean water solubility at 20 °C per loading rate:

100 mg test item / L: Solubility = < 5.7 µg test item / L
1000 mg test item / L: Solubility = < 5.7 µg test item / L

In each of the replicates the water solubility of the test substance was less than the limit of quantification (< 5.7 µg/L) of the analytical method.

Executive summary:

The objective of the study was to determine the water solubility of the test substance"Cadmiumselenide". For the complete test substance no single analytical method is available. The water solubility was determined using the flask method and estimated by analysis of the element cadmium using Inductively coupled plasma – atomic emission spectroscopy (ICP-AES).

Preliminary tests and measurements showed fluctuations at room temperature. Therefore it was decided with the sponsor to take different loading rates at 20 ° C rather than to determine the water solubility at different temperatures.

Mean water solubility at 20 °C per loading rate:

100 mg test item / L:              Solubility = < 5.7 µg test item / L

1000 mg test item / L:           Solubility = < 5.7 µg test item / L

 

In each of the replicates the water solubility of the test substance was less than the limit of quantification (< 5.7 µg/L) of the analytical method.

Description of key information

Cadmium selenide was determined to be insoluble in accordance with the flask method (OECD 105).

Key value for chemical safety assessment

Water solubility:

5.7 µg/L

at the temperature of:

20 °C

Additional information

The objective of the study was to determine the water solubility of the test substance"Cadmiumselenide". For the complete test substance no single analytical method is available. The water solubility was determined using the flask method and estimated by analysis of the element cadmium using Inductively coupled plasma – atomic emission spectroscopy (ICP-AES).

Preliminary tests and measurements showed fluctuations at room temperature. Therefore it was decided with the sponsor to take different loading rates at 20 ° C rather than to determine the water solubility at different temperatures.

Mean water solubility at 20 °C per loading rate:
100 mg test item / L:              Solubility = < 5.7 µg test item / L

1000 mg test item / L:           Solubility = < 5.7 µg test item / L

 

In each of the replicates the water solubility of the test substance was less than the limit of quantification (< 5.7 µg/L) of the analytical method.