Reaction mass of 3-[(2-aminoethyl)ammonio]propane-1-sulfonate and 3,3'-(ethane-1,2-diyldiammonio)dipropane-1-sulfonate and ethane-1,2-diamine

Adsorption / desorption

Administrative data

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study with GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC))

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.19 (Estimation of the Adsorption Coefficient (KOC) on Soil and Sewage Sludge Using High Performance Liquid Chromatography (HPLC))

Deviations:

no

GLP compliance:

yes

Type of method:

HPLC estimation method

Media:

other:

Test material

Test material information

Constituent 1

Reference substance name:

3-[(2-aminoethyl)amino]propane-1-sulfonic acid

Cas Number:

14235-54-2

Molecular formula:

C5H14N2O3S

IUPAC Name:

3-[(2-aminoethyl)amino]propane-1-sulfonic acid

Details on test material:

- Physical state: solid
- Analytical purity: approx. 95 %
- Impurities (identity and concentrations): water approx 5%
- Lot/batch No.: 06060423/101
- Stability under test conditions: stable
- Storage condition of test material: room temperature in the dark

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
- Water solubility:
The water solubility of "3-[(2-aminoethyl)ammonio]propane-1-sulfonate" was estimated to: >91 % (w/w) at 21 °C. The concentration is equivalent to
>1000 g/L. The test substance is miscible at any concentration with water. See Section 4.8. "Key. ARC-L-3110. Water solubility".

- pKa (Calculation by the software PALLAS pKa Prediction Module 5.1, version 3.4.1.3. ):
The calculated pKa's of the test substance are -1.9 (acidic group) and 7.6, 10.4 (basic groups).

Radiolabelling:

no

Study design

Test temperature:

35 °C

HPLC method

Details on study design: HPLC method:

SELECTION OF pH
According to the guideline two tests should be performed, for ionisable substances with both ionised and non-ionised forms but only in cases where at least 10 % of the test compound will be dissociated within pH 5.5 to 7.5
The calculated pKa's of the test substance are -1.9 (acidic group) and 7.6, 10.4 (basic groups). It was not possible to determine both, ionised and non-ionised forms between pH 5.5 and 7.5. Therefore only one experimental test at pH 6.5 was performed.

EQUIPMENT and MOBILE PHASES
System: Finnigan Surveyor Tox1
Column: LiChrospher 100 CN 5 µm 150*3 mm; Lot. No. Q31021 (ARC Seibersdorf)
Column temperature: 35 °C
Mobile phase: 40 % methanol (Sigma-Aldrich; Lot. No. 71270)
60 % buffer* pH 6.5 in water
Flow: 0.7 mL/min
Injection volume:10 L
Detection: UV-absorption at 210 nm
*buffer pH 6.5:
10 mMol/L potassiumdihydrogencitrate in water adjusted with sodium hydroxide to pH 6.5.
The pH of the mobile phase was determined during the run with a pH-meter (InoLab pH Level 2; WTW, Germany).

DETERMINATION OF DEAD TIME
The dead time t0 was determined by an unretained compound (sodium nitrate;assay > 99.5 %; Lot 50330; Riedel de Haen).

REFERENCE SUBSTANCES
substances purity(%) concentration in mobile phase (mg/L)
sodium nitrate;
batch no. 50330; Riedel de Haen >99.5 10.1

acetanilide;
batch no. 1291353; Fluka ≤99.5 9.8

methyl benzoate;
batch no. 1; Fluka 1336230 100 9.0

naphthalene;
batch no. 1348421; Fluka 99.9 11.0

"3-[(2-aminoethyl)ammonio]propane-1-sulfonate" 1000.5

DETERMINATION OF RETENTION TIMES
Calibration graph:
According to the guidelines a minimum of six reference points, if possible at least one above and one below the expected value of the test substance should be used.
Freshly prepared solutions of three reference compounds (see Table 1) in the mobile phase were injected individually to identify their peak in this
HPLC-system. Then they were injected simultaneously (before and after the test substance) and the exact retention times were determined in duplicate.The corresponding capacity factors and logarithms of the capacity factors were calculated and plotted as a function of the log KOC.
A linear regression line was calculated from the data of this graph. The log KOC values of the reference compounds are described in the guidelines.

Determination of the adsorption coefficient of the test substance:
Due to the low UV-absorption of the test substance the test was performed with a freshly prepared solution of 1000.5 mg of "3-[(2-aminoethyl)ammonio]propane-1-sulfonate" per litre mobile phase.
The retention time of the test substance was determined in duplicate and the capacity factor k' was calculated.

Results and discussion

Adsorption coefficient

Type:

log Koc

Value:

ca. 1.25

Results: HPLC method

Details on results (HPLC method):

The actual pH value of the mobile phase during the test was 6.5.
The temperature during the test was 35 °C.
The calibration curve of the reference substances was: log k' = 0.4003x log KOC – 0.4987.
The experimentally determined adsorption coefficient log KOC of "3-[(2-aminoethyl)ammonio]propane-1-sulfonate" is <1.25 at pH 6.5.(The log Koc was determined to be <1.25, and not ca. 1.25 as shown above. Only the "<" sign can not be entered there.)
The experimentally determined log KOC is outside the range (1.5 to 5.0) for which the method is published in the guideline. The log KOC was therefore only determined with three reference substances and no further tests were performed.

For graph of regression line see attachment "Regression line.jpg

Any other information on results incl. tables

Results for reference and test substances

substance	retention time (minutes)		capacity factor k'		mean log k'	log KOC*
	a	b	a	b
sodium nitrate	1.06	1.07	--	--	--	--
acetanilide	2.14	2.14	1.02	1.00	0.00	1.25
methyl benzoate	2.83	2.82	1.67	1.64	0.22	1.80
naphthalene	5.35	5.33	4.05	3.98	0.60	2.75
"3-[(2-aminoethyl)ammonio]propane-1-sulfonate"	1.08	1.08	0.02	0.01	-1.85	<1.25

*The log K_OC-values of the reference compounds are taken from the guidelines

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The experimentally determined adsorption coefficient log KOC of "3-[(2-aminoethyl)ammonio]propane-1-sulfonate" is <1.25 at pH 6.5.
The experimentally determined log KOC is outside the range (1.5 to 5.0) for which the method is published in the guideline.

Executive summary:

The adsorption coefficient log KOCof the test substance was determined by the HPLC method according to OECD- and EU-methods.

The calculated pKa's of the test substance are -1.9 (acidic group) and 7.6, 10.4 (basic groups). It was not possible to determine both, ionised and non-ionised forms between pH 5.5 and 7.5. Therefore only one experimental test at pH 6.5 was performed.

The experimentally determined adsorption coefficient log KOC of "3-[(2-aminoethyl)ammonio]propane-1-sulfonate" is < 1.25 at pH 6.5.

The temperature during the test was 35 °C.

The calibration curve of the reference substances was: log k' = 0.4003xlog K_OC– 0.4987.X