Aminoguanidinium hydrogen carbonate

Hydrolysis

Administrative data

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Aminoguanidinium hydrogen carbonate

EC Number:

219-956-7

EC Name:

Aminoguanidinium hydrogen carbonate

Cas Number:

2582-30-1

Molecular formula:

CH6N4.CH2O3

IUPAC Name:

N-aminoguanidine; carbonic acid

Constituent 2

Reference substance name:

Aminoguanidiniumhydrogencarbonat

IUPAC Name:

Aminoguanidiniumhydrogencarbonat

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Name of test material (as cited in study report):Aminoguanidiuniumhydrogencarbonat
- Physical state: light yellowish powder
- Lot/batch No.: 120708

Radiolabelling:

no

Study design

Analytical monitoring:

yes

Buffers:

Buffer Solution pH 4.0 0.1 mol/L: 1.37 g potassium dihydrogen phosphate were dissolved in approx. 100 ml water. Phosphoric acid (85 %) was used to adjust the pH to 4.0. The concentration of the resulting solution was approx. 0.1 mol/L.

Buffer Solution PH 7.0 0.1 mol/L: 1.36 g potassium dihydrogen phosphate were dissolved in approx. 100 ml water. Sodium hydroxide solution (32 %) was used to adjust the pH to 7.0. The concentration of the resulting solution was approx. 0.1 mol/L.

Buffer Solution pH 9.0 0.1 molg/l: TIER 1: 3.82 g sodium tetraborate decahydrate were dissolved in approx. 100 ml water. Hydrochloric
acid (25 %) was used to adjust the pH to 9.0. The concentration of the resulting solution was approx. 0.1 mol/L.

TIER 2: 38.16 g sodium tetraborate decahydrate were dissolved in approx. 1000 ml water. Hydrochloric acid (25 %) was used to adjust the pH to 9.0. The concentration of the resulting solution was approx. 0.1 mol/L.

Details on test conditions:

An alteration of the buffered test item solutions after sampling occurred because of the storage at approx. -20 °C in the first execution of the study. Furthermore, the number of sampling points in the initial phase of TIER 2 were insufficient to monitor the time dependent degradation Due to this issues, it was necessary to repeat the main study. Within the repetition , sampled solutions were analysed immediately and a sufficient number of sampling points was chosen. The performance and results of the repetition are presented in the following sections.

Stock solutions of the test item with a concentration of approx. 2.0 g/L were prepared by weighing the required test item amount into a volumetric flask and filling the flask to volume with Milli-Q water.
Buffer solutions (approx. 0.1 mol/L, pH 4, pH 7, and pH 9, see section 4.4) were used to retain the required pH value during the whole test period. Therefore, a buffered test item solution was prepared containing approx. 1.0 g/L (~approx . 0.007 mol/L) of the test item and approx. 0.05 mol/L buffer by mixing equal volumes of the test item stock solution (2.0 g/L) and buffer solution (approx. 0.1 mol/L). The pH value of each test item solution was verified by pH measurement with a pH-meter or suitable indicator strips. For the buffered test item solution at pH 4, additional pH adjustment with cone. hydrochloric acid was necessary. Supplementary, buffered blank solutions were prepared for each pH value by mixing equal volumes of buffer stock solution {approx. 0.1 mol/L) and Milli-Q water.

Referred to OECD 111 the test item was found to be unstable at pH 9 at 50 °C (degradation > 10 %; see section 5.1.2). Therefore, TIER 2 was performed at pH 9 for three different incubation temperatures (24.5 °C, 50 °C, and 70 °C).

Duration of test

Duration of test 1

Duration:

5 d

Temp.:

50 °C

Duration of test 2

pH:

9

Number of replicates:

Tier 1: 6
Tier 2: 4

Results and discussion

Dissipation DT50 of parent compound

Dissipation DT50 of parent compound 1

pH:

4

Temp.:

25 °C

DT50:

> 1 yr

Type:

(pseudo-)first order (= half-life)

Dissipation DT50 of parent compound 2

pH:

7

Temp.:

25 °C

DT50:

> 1 yr

Type:

(pseudo-)first order (= half-life)

Dissipation DT50 of parent compound 3

pH:

9

Temp.:

25 °C

DT50:

ca. 1 yr

Type:

(pseudo-)first order (= half-life)

Any other information on results incl. tables

Final Data Tier 1

pH	Temp. [°C]	Duration [d]	Degradation [%]
4	50	5	3.4
7	50	5	2.8
9	50	5	11.5

In Tier 1 the test item was found to be hydrolytically stable at Ph 4 and pH 7. However, more than 10% degradation occurred in Tier 1 for pH9. Therefore, Tier 2 was performed at this pH value at 24.5 °C, 50 °C and 70 °C. The determined data suggests a pseudo first-order reation as the reaction mechanism for the hydrolysis under these conditions.

Hydrolysis Condition	Half-Life of Test item at 25°C
Acidic (pH 4)	> 1 year
Neutral (pH 7)	> 1 year
Basic (pH 9)	Approx. 1 year