Phosphinic acid

pH

Administrative data

Endpoint:

pH

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Test procedure in accordance with generally accepted scientific standards and described in sufficient detail.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

no guideline available

Guideline:

other: supplement of guideline 404 and 405

Deviations:

no

Principles of method if other than guideline:

10 g of the test substance (liquid or solid) is added to 100 mL of distilled water in a 250 mL beaker. The solution or suspension is maintained for 4 hours with agitation at 37°C. Then the pH is directly measured in the solution or the aqueous phase of suspensions (after decantation or centrifugation). The sample is then titrated with diluted sodium hydroxide or hydrochloric acid until neutrality is obtained. A preliminary titration was performed for a preliminary test to allows good conditions for the alkaline reserve (R) determination: 10 mL volume of a 100 g/L solution are neutralised by approximately 95 mL of 0,1 N NaOH.
Then for a definitive test, the titration was performed three times more in the same conditions.

The acidic or alkaline reserve (R) is expressed as the number of grams of pure acid or base necessary to neutralise 100 g of product (%).

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Phosphinic acid

EC Number:

228-601-5

EC Name:

Phosphinic acid

Cas Number:

6303-21-5

Molecular formula:

H3O2P

IUPAC Name:

phosphinic acid

Test material form:

other: aqueous solution

Details on test material:

Sample designation:
- Name of test material: phosphinic acid
- Physical state: clear liquid
- Date of reception in the test facility: 2009.12.23

Results and discussion

pH value

pH value:

0.71

Temp.:

37 °C

Concentration:

100 g/L

Any other information on results incl. tables

Under the test conditions, the aqueous phosphinic acid shows an acidic character demonstrated by a pH of 0,71 for a 100 g/L solution in water, an alkaline reserve of 38,015 (i.e log R = 1,580) and a physicochemical index of 14,870.

Table 1 : Results of neutralization experiments

Replicate  Hypophorous acid 100 g/L, mL  NaOH 0,1 N, mL Initial pH  Final pH   R  Log (R)  I  1  10 95,110  0,71  7,01         38,015   1,580      14,870     2  10 95,160 0,71 7,04  3  10 95,190 0,71 7,01

Applicant's summary and conclusion

Conclusions:

Under the test conditions, the aqueous phosphinic acid shows an acidic character demonstrated by a pH of 0.71 for a 100 g/L solution in water, an alkaline reserve of 38,015 (i.e log R = 1,580) and a physicochemical index of 14,870.

Executive summary:

The pH and Alkaline reserve of the test item phosphinic acid was measured according to the method described in the two following references JF.Regnier and C.Imbert (1992), and V.Froment (1993).

This method can be used at first step of stepwise strategy for assessing cutaneous and ocular irritation.

An amount of the test substance is added to distilled water in a beaker. The solution or suspension is maintained for 4 hours with agitation at 37° C. The pH is directly measured and the sample is then titrated with diluted sodium hydroxyde or hydrochloric acid until neutrality is obtained. The acidic or alkaline reserve (R) is expressed as the number of grams of pure acid or base necessary to neutralise 100 g of product (%).

A preliminary titration was performed for a preliminary test to allows good conditions for the alkaline reserve (R) determination: 10 mL volume of a 100 g/L solution are neutralised by approximately 95 mL of 0.1 N NaOH. Then for a definitive test, the titration were performed three times more in the same conditions.

Under the test conditions, the aqueous phosphinic acid shows an acidic character demonstrated by a pH of 0,71 for a 100 g/L solution in water, an alkaline reserve of 38,015 (i.e log R = 1,580) and a physicochemical index of 14,870.