Ammonium dihydrogen citrate

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
For environmental toxicity citric acid and ammonium citrate dibasic can be considered to be representative for ammonium dihydrogen citrate. The source chemicals for read across are salts that contain one of the ions and/or citric acid.

2. SOURCE AND TARGET CHEMICAL(S)
SOURCE Chemicals:
* Diammonium citrate, CAS no. 3012-65-5
* Citric acid, CAS no. 77-92-9
TARGET Chemical: Ammonium dihydrogen citrate

3. ANALOGUE APPROACH JUSTIFICATION
Diammonium citrate and the target substance only differ in presence of an ammonium ion, but the main determinant for the partition coefficient is the citrate as the ammonium part is inorganic.
Under the test circumstances of the partition coefficient test (pH=7), for both diammonium citrate and ammonium dihydrogen citrate the citrate is expected to be present in ionized form. Therefore it can be concluded that the partition coefficient will be similar for ammonium citrate dibasic and the target substance and that it is scientifically valid to read-across this value.

4. DATA MATRIX
* Diammonium citrate: Log Pow <0
* Citric acid: Log Pow -0.76 for H2A- and -0.21 for H3A; otherwise log Pow -1.7 or lower

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Key result

Type:

log Pow

Partition coefficient:

< 0

Remarks on result:

not measured/tested

Remarks:

result based on read-across from 2 sources

Details on results:

Considering that the substance is produced in water, and very well soluble in water, the provided analogue data support the theory that the Log Pow of ammonium dihydrogen citrate is <0.

Conclusions:

The log Pow of the test item is <0, based on read across from 2 sources.

Description of key information

The log Pow of the substance is estimated to be <0, based on read-across from data for diammonium citrate (HPLC method at pH 7.7 acc to OECD 117) and data for citric acid (various peer-reviewed data sources).

Read-across is considered justified because the main determinant for the partition coefficient is the citrate ion, as the ammonium part is inorganic. Also, the target substance is well soluble in water, which supports the theory that the Log Pow of ammonium dihydrogen citrate is <0.