Hexasodium 4,4'-[1,4-phenylenebis[imino(6-chloro-1,3,5-triazine-4,2-diyl)imino]]bis[5-hydroxy-6-[(2-sulphonatophenyl)azo]naphthalene-2,7-disulphonate]

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

22 September 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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))

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))

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Radiolabelling:

no

Test temperature:

column temperature 25 ± 1 °C

Details on study design: HPLC method:

EQUIPMENT
- Apparatus: Agilent
- Type: HPLC/UV
- Type, material and dimension of analytical (guard) column: Reprosil PurCN 125*4.6 mm with pre-column Phenom-enex SecurityGuard CN, 4*3 mm
- Injection volume 20 µL
- Column temperature 25 ± 1 °C.
- Detection system: UV at 230 nm

MOBILE PHASES
- Type: isocratic methanol/water 55/45 (% v/v), degassed
- Flow rate 0.8 mL/min
- pH: 7.3
- Solutes for dissolving test and reference substances: methanol/water 55/45 (% v/v)

DETERMINATION OF DEAD TIME
- Method: by inert substances which are not retained by the column: sodium nitrate

REFERENCE SUBSTANCES: Phenol, Methylbenzoate, Naphthalene, 1,2,3-Trichlorobenzene, Phenanthrene, DDT

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 20 ug/L
- Concentration of reference substances:
Sodium nitrate 1000 mg/L
Phenol 10000 µL/L
Methylbenzoate 1000 mg/L
Naphthalene 91-20-3 1000 mg/L
1,2,3-Trichlorobenzene 1000 µL/L
Phenanthrene 1000 mg/L
4,4’-DDT 1000 mg/L
- Intervals of calibration: Three injections were measured from the reference item mix, three injections from the test item solution and again three injections from the reference item mix.

REPETITIONS

EVALUATION
- Calculation of capacity factors k':
- Calculation of retention times:
- Determination of the log Koc value:

Sample No.:

#1

Type:

log Koc

Value:

< 1.3 dimensionless

pH:

7.3

Temp.:

25 °C

Remarks on result:

not determinable

Remarks:

elution in the dead time

Sample No.:

#2

Type:

log Koc

Value:

< 1.3 dimensionless

pH:

7.3

Temp.:

25 °C

Remarks on result:

not determinable

Remarks:

elution in the dead time

Sample No.:

#3

Type:

log Koc

Value:

< 1.3

pH:

7.3

Temp.:

25 °C

Remarks on result:

not determinable

Remarks:

elution in the dead time

Details on results (HPLC method):

see table

Log k’ and log K_OCof Reference Items

Compound	log k’	log KOC
Phenol	0.1482	1.32
Methylbenzoate	0.2304	1.80
Naphthalene	0.3790	2.75
1,2,3-Trichlorobenzene	0.4321	3.16
Phenanthrene	0.5798	4.09
DDT	0.8421	5.63

calibration: log k’ = 0.1593 * logK_OC– 0.0625 with a coefficient of determination r²= 0.9991.

Results test item

Peak 1 Test Item	RT (min	k’	logk’	log KOC
Measurement 1	0.930	-0.1123	n.c.*	n.c.*
Measurement 2	0.931	-0.1115	n.c.*	n.c.*
Measurement 3	0.932	-0.1102	n.c.*	n.c.*
Mean	0.931			n.c.*
Standard deviation	0.001			n.c.*

* Not calculable, because k’ is negative. The retention time of peak 1 is lower than the retention time of sodium nitrate, which was used for the determination of the dead time of the method.

Conclusions:

The Koc could not be calculated due to elution of the substance in the dead time. The logKoc is therefore indicated to be < 1.3

Executive summary:

The study was performed using the HPLC method

The chromatogram of the test item gave one peak (mean RT = 0.931 min). The log K_OC of peak 1 was not calculable, because its retention time lay below the retention time of sodium nitrate (dead time marker). The log K_OCof the test item is stated as < 1.3 (logKoc of phenol).

 

Peak	Mean retention time [min]	Log KOC
Peak 1	0.931 ± 0.001	< 1.3*

*not calculable, elution in the dead time

These values are the means ± standard deviation of three independent determinations

Description of key information

The Koc could not be calculated due to elution of the substance in the dead time. The logKoc is therefore indicated to be < 1.3

Key value for chemical safety assessment

Koc at 20 °C:

19.9