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Study Title

Adsorption Coefficient of 

1,1’-(1,6-hexanediyldiimino)bis[1-oxo-methanesulfonic acid], sodium salt (1:2) 

Data requirements

REACH requirement EC/1907/2006 

Author

M. T. Garcia-Sanchez 

Study completion date

2012-02-16 

LANXESS Deutschland GmbH

51369 Leverkusen 

Germany 

Testing facility

CURRENTA GmbH & Co. OHG 

Analytik

51368 Leverkusen 

Germany 

Laboratory Project Identification

Study No.: 2011/0125/04 
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CURRENTA GmbH & Co. OHG

Analytik 

Study No.: 2011/0125/04

This page is intentionally left blank for the purpose of submitting administrative

information that is required by regulations promulgated by various countries.
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CURRENTA GmbH & Co. OHG

Analytik 

Study No.: 2011/0125/04

CONTENTS

Page 

1. GLP DECLARATION 4

2. ARCHIVING 4

3. QUALITY ASSURANCE STATEMENT _ 6

4. STUDY TIME TABLE 6

5. GLP CERTIFICATE 7

6. SUMMARY _ 8

7. EXPERIMENTAL PROCEDURE 9

7.1. Methods, guidelines and documents 9

7.2. Principle of the test 9

8. TEST MATERIAL 11

8.1. Sample description 11

8.2. Calibration substances 11

9. METHODS AND RESULTS 12

9.1. Determination of the pH-value of the aqueous part of the mobile

phase 12

9.2. Determination of the adsorption coefficient 12

9.2.1. Preparation of the test solutions 12 

9.2.2. HPLC-method parameters 12 

9.2.3. Example chromatograms 14 

9.2.4. Calibration 15 

9.2.5. Determination of the test item 16 
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CURRENTA GmbH & Co. OHG Study No.: 201110125104 

Analytik

1. GLP DECLARATION

This study was conducted in compliance with the OECD principles of Good

Laboratory Practice (1999) and with the Principles of Good Laboratory Practice

according to Annex 1, German Chemical Law (2008).

Date I Signature

Study Director <

M. T. Garcia-Sanchez

Date I Signature

Head of Test Facility

2. ARCHIVING

The original report, the study plan, and all raw data pertaining to this study are stored

in the "GLP Archive, CURRENTA GmbH & Co. OHG, Analytik , CHEMPARK,

Building Q 18, D-51368 Leverkusen". A sample of the test item is stored in 

"GLP-Sample Store, CURRENTA GmbH & Co. OHG, Analytik , CHEMPARK,

Building DA 1, D-41538 Dormagen".
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CURRENTA GmbH & Co. OHG Study No.: 2011/0125/04 

Analytik 

This page is intentionally left blank for the purpose of submitting administrative

information that is required by regulations promulgated by various countries.
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CURRENTA GmbH & Co. OHG

Analytik

Study No.: 201110125104 

3. QUALITY ASSURANC E STATEMENT

This report was audited by the Quality Assurance Unit Currenta, Analytik, Quality

Management at Currenta GmbH & Co . OHG and this statement confirms that the

final report reflects the raw data.

The dates of Quality Assurance inspections and audits are given below.

Audits Dates of QAU

Inspections

Dates of 

Reports

study plan review

process based inspection

final report review (draft) 

final report review

2012-01-12

2011-12-20

2012-01-23

.2l'JI2 0 2 I G

2012-01-12

2011-12-20

2012-01-23

J..-o/2 o;: -IG

Date I Signature

012 02 ·IIG // dfl-·A '(

Ms Senic I Brl3err-B-asl:l-baA§e-1-Br-Netlpert 

4. STUDY TIME TABLE

Study initiation date: 2012-01-12

Study completion date: 2012-02-16

Start of experimental tests: 2012-01-18

End of experimental tests: 2012-01-20
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Study No.: 2011/0125/04

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5. GLP CERTIFICATE

Please note: 

Effective January 1st, 2008, the company name Bayer Industry Services GmbH & Co.

OHG was changed to CURRENTA GmbH & Co. OHG. 
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Study No.: 2011/0125/04

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6. SUMMARY

For 1,1’-(1,6-hexanediyldiimino)bis[1-oxo-methanesulfonic acid], sodium salt (1:2),

batch no.: RJE 76081 the adsorption coefficient was estimated by the HPLC-method

according OECD TG 121. 

The adsorption coefficient of the test item is estimated to be:

log Koc = < - 3.6

Extrapolated value. 

Retention time of the test item set to 2.0 min. for the calculations (see 9.2.5) 
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Study No.: 2011/0125/04

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7. EXPERIMENTAL PROCEDURE

7.1. Methods, guidelines and documents

The determination of the partition coefficient by the HPLC-method was based on the

following guidelines: 

OECD Guidelines for Testing of Chemicals No.: 121 “Estimation of the Adsorption

Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid

Chromatography (HPLC)” (adopted, January 2001) 

SOP 00193 Version 3, this SOP corresponds to Council Regulations EC No

440/2008, Guideline Part C – Methods for the Determination of Ecotoxicity, C.19.

“Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using

High Performance Liquid Chromatography (HPLC)” (adopted, May 2008). 

SOP 00178 Version 2 for the determination of the pH-value from the aqueous part of

the mobile phase. 

7.2. Principle of the test

The adsorption coefficient (K) is a partition coefficient and is defined as the ratio of

the equilibrium concentrations of a dissolved substance in a two-phase system

consisting of a sorbent (soil or sewage sludge) and an aqueous phase. 

Koc = Csoil (sludge) 

Cwater

HPLC is performed on analytical columns packed with a commercially available

cyano solid phase chemically bound onto silica. Chemicals injected onto such a

column move along it by partitioning between the mobile solvent phase and the

stationary cyano-phase. The chemicals are retained in proportion to their solid

phase/water partition coefficient, with water-soluble chemicals eluted first and soil

(sludge)-soluble chemicals last. This enables the relationship between the retention

time on a cyano phase column and the soil(sludge)/water adsorption coefficient to be

established. The adsorption coefficient is deduced from the capacity factor (k), given

by the expression where, tR is the retention time of the test item, and t0 is the deadtime, i.e. the average time a solvent molecule needs to pass the column. Quantitative

analytical methods are not required; only the determination of retention times is

necessary. 

The HPLC method enables adsorption coefficients to be estimated in the log Koc 

range between 1.5 and 5. The pH value has a significant influence on sorption

behaviour in particular for polar substances. For agricultural soils or tanks of sewage

treatment plants pH normally varies between pH 5.5 and 7.5. For this reason the test

is performed at pH 6 (e.g. by adding citrate buffer to the mobile phase). 
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In case more than 10 % of the test item is dissociated at pH 6, a second test has to

be performed at a pH where the test item is undissociated. 

The test substance is a sodium salt of an aliphatic sulfonic acid, these salts are

dissociated in water. Therefore there is no pH range where the nonionic form of the

test item exists. The test was performed at pH 6 (environmental relevant) 
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8.1.

8.

Sample description

TEST MATERIAL

Test item: 1,1’-(1,6-hexanediyldiimino)bis[1-oxomethanesulfonic acid], sodium salt (1:2) 

CAS name: 1,1’-(1,6-hexanediyldiimino)bis[1-oxomethanesulfonic acid], sodium salt (1:2) 

CAS number: 38632-47-2 

Empirical formula: C8H14N2O8S2.2Na

Molecular mass: 376.3 g/mol 

Batch number: RJE 76081 

Sample number: 1452 

Date of receipt: 2011-10-07 

Expiry date: 2013-10-10 

Storage conditions: Room temperature 

Structural formula: 

2-

O O

O H O–

S N 

–O H

O 

N S

O

2 Na

O

8.2. Calibration substances

The reference substances used for calibration are mentioned in paragraph 9.2.4. 
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9. METHODS AND RESULTS

9.1. Determination of the pH-value of the aqueous part of the mobile 

phase

Method: SOP 00178 version 2

Supervisor: J. Leibold 

Procedure: 

The pH determination of the aqueous part of the mobile phase was done with a pH

meter equipped with a calibrated single-rod glass electrode. 

Result: pH 6.3 

9.2. Determination of the adsorption coefficient

Method: SOP 00193 Version 3

Supervisor: J. Leibold 

9.2.1. Preparation of the test solutions 

The calibration substances solutions were dissolved in a mixture of 30 % water and

70 % acetonitrile. The concentrations of the calibration substances after dilution with

acetonitrile to the measuring concentration were between 0.05 mg /ml and 0.17

mg/ml. 

The solution for the determination of the dead time was prepared by dissolving

sodium nitrate in a mixture of 30 % water and 70 % acetonitrile. The sodium nitrate

solution was diluted to a final concentration of 0.11 mg/ml with acetonitrile. 

The test item was dissolved in water. The concentration of the test item after dilution

with acetonitrile to the measuring concentration was 0.31 mg/ml. 

9.2.2. HPLC-method parameters 

Equipment: HPLC Agilent 1100 

Column: LiChrospher 100 CN, 250 mm length, 

4 mm internal diameter, 5 μm particle size 

Eluent A: 835 ml water + 165 ml buffer pH 6 
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Eluent B: acetonitrile 

Solvent program: Isocratic 70 % A and 30 % B

Flow: 1 ml/min 

Column temperature: 40 °C

Injection volume: 5 μL 

Detector: UV, 210 nm 

Acetonitrile, Fa. Merck, Lichrosolve, Art-Nr.: 1.00030

Buffer pH 6, Fa. Sigma Aldrich, Art-Nr.: 33545

Demineralized water 

Remark:

In order to ensure a stable performance of the HPLC column, the column temperature was set to 40°C.

The reference Koc-values in the OECD guideline presumably refer to 25°C. Even though the column

temperature was 40°C, this temperature has no influ ence on the result of the determination. Therefore

the Koc -value of the test item determined within this study also refers to 25 °C
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9.2.3. Example chromatograms 

Figure 1: HPLC-chromatogram of the calibration substances and the test item 

Figure 2: HPLC-chromatogram of the test item. 
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Results 

9.2.4. Calibration 

Table 1: Calibration substances (individual values) 

Calibration substance Retention time

tR in min

Test 1

Retention time

tR in min

Test 2

Retention time

tR in min

Test 3

Retention time

tR in min

Mean value

Sodium nitrate (dead time (t0)) 1.907 1.907 1.908 1.907

Acetanilide 3.848 3.848 3.849 3.848

Methylbenzoate 5.150 5.149 5.151 5.150

Thiazoxide 6.473 6.473 6.472 6.473

Naphthalene 8.530 8.526 8.523 8.526

1,2,3-Trichlorobenzene 9.803 9.796 9.792 9.797

Phenanthrene 14.216 14.195 14.185 14.199

Table 2: Calibration substances (mean values) 

Calibration substance Retention time

tR in min

Mean value

Capacity

factor k’

log k’ log Koc *

Sodium nitrate (dead time (t0)) 1.907 - - -

Acetanilide 3.848 1.018 0.008 1.25

Methylbenzoate 5.150 1.700 0.230 1.80

Thiazoxide 6.473 2.393 0.379 2.44

Naphthalene 8.526 3.470 0.540 2.75

1,2,3-Trichlorobenzene 9.797 4.137 0.617 3.16

Phenanthrene 14.199 6.444 0.809 4.09

* OECD Guidelines for Testing of Chemicals No.: 121, table 3, recommended reference

substances.
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Test item Retention

time tR in

min

Test 1

Retention time

tR in min

Test 2

Retention time

tR in min

Test 3

Retention time

tR in min

Mean value

1,1’-(1,6-hexanediyldiimino)bis[1-

oxo-methanesulfonic acid],

sodium salt (1:2)

1.671 1.671 1.672 1.671

a = - 0.2985 

b = 0.282 

r = 0.989 

Capacity factor k’ = (tR – t0) / t0 

tR: retention time of the substance

t0: dead time

Effective correlation log k’ = a + b log Koc

Linear regression gives: 

where a and b are the regression factors and r is the correlation factor. 

9.2.5. Determination of the test item

Table 3: Test item (individual values) 

Table 4: Test item evaluation 

Test item Retention

time tR in

min

Mean value

Capacity

factor k’

log k’ log Koc

1,1’-(1,6-hexanediyldiimino)bis[1-

oxo-methanesulfonic acid],

sodium salt (1:2)

< 2.0 < 0.049 < - 1.313 < - 3.59
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CURRENTA GmbH & Co. OHG Study No.: 2011/0125/04 

Analytik 

Remark: 

No reference substance with a log Koc value under the value for the test item is 

available. The result was extrapolated. 

The test item showed a lower retention time (tr =1.67 min.) than the dead time marker 

sodium nitrate (tr =1.91 min.). For the calculation of the adsorption coefficient, the 

retention time for the test item is set to tr = 2.0 min. Otherwise a calculation would 

have not been possible. 

Figure 3: Graphic of the linear regression log k’ / log Koc of test item 

and calibration substances 

The adsorption coefficient of the test item is estimated to be: 

log Koc < - 3.6

Extrapolated value. 

Retention time of the test item set to 2.0 min. for the calculations