Potassium pentaborate

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

04/06/2010 to 01/07/2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

not specified

GLP compliance:

yes

Type of method:

flask method

Water solubility:

38.9 g/L

Conc. based on:

test mat.

Loading of aqueous phase:

191.6 g/L

Incubation duration:

24 h

Temp.:

20 °C

pH:

7.9

Remarks on result:

other: calculated based on the measured weight% assuming a density of 1 g/mL

Water solubility:

3.89 other: % w/w

Conc. based on:

test mat.

Loading of aqueous phase:

191.6 g/L

Incubation duration:

24 h

Temp.:

20 °C

pH:

7.9

Remarks on result:

other: Calculated from the titration for boric oxide

Preliminary Test:

Weight of test item used = 0.1006

Temperature of test = 20 °C

Total Volume of distilled water added (mL)	0.1	0.5	1	2	10	100	>100
Was test item totally dissolved? (y/n)	No	No	No	No	Yes	N/A	N/A
Approximate solubility (g/L)	> 1000	1000 - 200	200 - 100	100 - 50	50 - 10	10 - 1	< 1

Shake Flask Test: 

Based on the preliminary test the water solubility of the test item is from 10 – 50 g/L. The MSDS for the test item stated that the water solubility was 38 g/L which is within this range. The amount of test item required for 1 L of water would be 5 x 38 = 190 g and as this test is done in triplicate the total amount of test item is 190 x 3 = 570 g. However based on the approximate amount of test item available the maximum weight of test item available for each replicate was19 g. Based on the MSDS solubility of 38 g/L then the amount of water required for 19 g of test item would be: (19/5)/38 x1000 = 100 mL

Approximately 19 g of test item was then accurately weighed into each of three flasks, 100 mL of distilled water was added to each and the flasks were then placed in a temperature controlled shaker at 30°C. Testing was then carried out.

Shake Flask Details:

Replicate Number	Weight of test item used (g)	Volume of distilled water added (mL)	Number of days shaking	pH of aqueous solution after shaking, 24 hours in 20°C water bath and centrifugation and filtration
Replicate 1	19.1588	100	1	7.86
Replicate 2	19.0759	100	2	7.93
Replicate 3	19.0508	100	3	7.88

After removal from the shaker the test item solutions were placed in a water bath, set at 20°C, for 24 hours prior to centrifugation, filtration and analysis. However due to a delay in the analysis the centrifuged and filtered aqueous test item solutions were placed back in the 20°C water bath and kept at temperature until analysed.

Water Solubility Solution Analysis Results:

Replicate Number	Volume of aqueous test item solution taken (mL)	Weight of aqueous test item solution taken (g)	Volume of 0.5N hydrochloric acid added (mL)	Volume of 0.5N sodium hydroxide added at first titration end point (mL)	Potassium oxide content (% w/w)	Potassium pentaborate content (% w/w)	Volume of 0.5N sodium hydroxide added at second end point (after addition of mannitol) (mL)	Boric oxide content (% w/w)	Potassium pentaborate content (% w/w)
Replicate 1	5	5.0929	25	23.3	0.66	4.09	6.75	2.31	3.90
Replicate 2	10	10.1624	25	21.90	0.65	4.07	13.50	2.32	3.91
Replicate 3	10	10.1936	25	21.95	0.64	3.99	13.40	2.29	3.86
				Mean =	0.65	4.05	Mean =	2.31	3.89
				SD =	0.0087	0.054	SD =	0.013	0.021
				%RSD =	1.33	1.33	%RSD =	0.55	0.55

Conclusions:

The resulting solutions from the water solubility testing were analysed for active content using British Standard Method BS 5688 Part 8. The mean water solubility was found to be 3.89 % w/w (38.9 g/L) (calculated from the titration for boric oxide).

Executive summary:

The water solubility was analysed following EU Method A.6 under GLP comliance. Flask method was used. The resulting solutions from the water solubility testing were analysed for active content using British Standard Method BS 5688 Part 8. The mean water solubility was found to be 3.89 % w/w (38.9 g/L assuming a density of 1 g/mL) at 20 °C (calculated from the titration for boric oxide).

Description of key information

The water solubility was analysed following EU Method A.6 under GLP comliance. Flask method was used. The resulting solutions from the water solubility testing were analysed for active content using British Standard Method BS 5688 Part 8. The mean water solubility was found to be 3.89 % w/w (38.9 g/L assuming a density of 1 g/mL) at 20 °C (calculated from the titration for boric oxide).

Key value for chemical safety assessment

Water solubility:

38.9 g/L

at the temperature of:

20 °C