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Reference
Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
03-09-2010 to 25-09-2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP and OECD guideline followed
Qualifier:
according to
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:
EU Method C.19 (Estimation of the Adsorption Coefficient (KOC) on Soil and Sewage Sludge Using High Performance Liquid Chromatography (HPLC))
GLP compliance:
yes
Type of method:
HPLC estimation method
Media:
soil/sewage sludge
Radiolabelling:
no
Test temperature:
The column temperature during the study was monitored every 2 min by a data logger. Details are given in Table 1.

Table 1: Temperature range
Determination at pH 7 Determination at pH 3
Min. Temperature 19.9 °C 20.0 °C
Max. Temperature 20.3 °C 20.2 °C
Mean Value 20.0 °C 20.1 °C
Details on study design: HPLC method:
Analyses of 4-Aminophenol were carried out by high performance liquid chromatography (HPLC) with an analytical column packed
with cyanopropyl (CN-) solid phase. The test item was dissolved in acetonitrile and then diluted in mobile phase and injected into the HPLC where the test item interacted with the stationary phase while passing through the column.

CONDITIONS OF ANALYSIS

Injection volume: 100 µL
Mobile phase 1) 50 % acetonitrile : 50 % pH 7 buffer [(HPO42-/H2PO4-) 0.01 mol/L] (v/v)
2) 50 % acetonitrile : 50 % pH 3 buffer [(HPO42-/PO43-) 0.01 mol/L] (v/v)
Column temperature 20 °C
Flow 1 mL/minute
Wavelength 1) 240 nm for analysis at pH 7
2) 220 nm and 275 nm for analysis at pH 3

Run time 15 miniutes

Calibration The method was calibrated by determination of the retention times tR of the reference items for soil and for sewage sludge.

UV using DAD (PDA) detector
HPLC-column YMC-Pack Cyano, serial no. 70823 11353, 250 x 4.0 mm,
batch 6703, YMC EUROPE GMBH

TEST ITEM 4-Aminophenol

Stock solutions 100 mg/L in acetonitrile (separate solutions for pH 3 and pH 7)

Test concentration 2 mg/L

Dilution With acetonitrile and buffer to mobile phase ratio

Replicates Triplicates (three injections)


REFERENCE ITEMS Reference items as specified in part 3. NaNO3 was used for determination of the dead time.

Stock solutions 100 mg/L each in acetonitrile
100 mg/L in mobile phase for NaNO3

Test concentrations 2 mg/L (nominal) of each reference item in separate solution

Dilution In mobile phase

Replicates Two injections (one before and one after the analysis of the
test item)

Three injections for NaNO3 at the beginning of the sample set.

A threefold determination of the dead time to was performed with a solution of 2 mg/L NaNO3 in mobile phase. Mean value was calculated.

Determination of the retention times tR of the eight reference items. Each reference item was analysed separately before and after analysis of the test item.

The retention time tR of the test item was determined with three injections.

Evaluation and plotting of the calibration graph log Koc vs. log k’ of six reference items for soil / sewage sludge.

Recording of the temperature during the whole study.

Computational methods:
Capacity factor :The capacity factor k’ was calculated according to equation (1): k'= (tR-t0) / t0

tR Retention time [min]
t0 Dead time [min]
k’ Capacity factor

Adsorption coefficient: By means of the adsorption coefficient values (KOC) and the corresponding capacity factors of the reference items calibration graphs of log KOC, soil versus log k’ and log KOC,sewage sludge versus log k’ were plotted.
Type:
log Koc
Remarks:
soil
Value:
0.59
Temp.:
20 °C
Remarks on result:
other: pH 7; undissociated form
Type:
Koc
Remarks:
soil
Value:
3.85
Temp.:
20 °C
Remarks on result:
other: ph 7;undissociated form
Type:
log Koc
Remarks:
sewage sludge
Value:
0.51
Temp.:
20
Remarks on result:
other: ph 3; undissociated form
Type:
Koc
Remarks:
sewage sludge
Value:
3.22
Temp.:
20 °C
Remarks on result:
other: pH 7; undissociated form
Details on results (HPLC method):
The estimated values of log KOC and KOC for pH 3 (dissociated form):
Soil Sewage Sludge
log KOC, soil KOC, soil log KOC, sewage sludge KOC, sewage sludge
-1.27 0.054 -1.17 0.068
According to the Mc Call classification scheme the dissociated form of the test item is classified as very high mobile in soil.

• The calculated values for log KOC of the injections for the test item did not differ more than ± 0.25.

Table2:   Dead Time of the HPLC-System

Serial No.

Determination at pH 7

Determination at pH 3

t0
[min]

t0
[min]

1

1.741

2.278

2

1.740

2.278

3

1.739

2.279

Mean ± SD

1.740±0.001

2.278±0.001

            SD = Standard deviation

Table5:   Retention Times, Capacity Factors (k’) and Adsorption Coefficient (KOC) of
4-Aminophenolfor Soilat pH 7

 

tR
[min]

k'

log k'

KOC, soil

logKOC, soil

∆ logKO, soil

4-Aminophenol

2.705

0.555

-0.2557

3.85

0.586

0.00

2.705

0.555

-0.2557

3.85

0.586

2.706

0.555

-0.2557

3.85

0.586

Mean

2.705

0.555

-0.2557

3.85

0.59

 

SD

0.000

0.000

0.0020

0.003

0.00

CI 95%

 

0.15 to 1.02

 

tR= Retention time; SD = Standard deviation; CI = Confidence Interval

 

 

Table6:   Retention Times, Capacity Factors (k’) and Adsorption Coefficient (KOC) of
4-Aminophenolfor Sewage Sludgeat pH 7

 

tR
[min]

k'

log k'

KOC, sewage sludge

logKOC, sewage sludge

∆ logKOC, sewage sludge

4-Aminophenol

2.705

0.555

-0.2557

3.22

0.508

0.00

2.705

0.555

-0.2557

3.22

0.508

2.706

0.555

-0.2557

3.22

0.508

Mean

2.705

0.555

-0.2557

3.22

0.51

 

SD

0.000

0.000

0.0020

0.003

0.00

CI 95%

 

-0.29 to 1.30

 

 

tR= Retention time; SD = Standard deviation; CI = Confidence Interval

Table7:   Retention Times, Capacity Factors (k’) and Adsorption Coefficient (KOC) of
4-Aminophenolfor Soil at pH 3

 

tR
[min]

k'

log k'

KOC, soil

logKOC, soil

∆ logKO, soil

4-Aminophenol

2.568

0.127

-0.8962

5.61×10-2

-1.251

0.02

2.566

0.126

-0.8996

5.35×10-2

-1,272

2.565

0.126

-0.8996

5.35×10-2

-1.272

Mean

2.566

0.126

-0.8995

5.44×10-2

-1.27

 

SD

0.000

0.001

0.0020

1.50×10-3

0.01

CI 95%

 

-2.25 to -0.29

 

tR= Retention time; SD = Standard deviation; CI = Confidence Interval

 

 

Table8:   Retention Times, Capacity Factors (k’) and Adsorption Coefficient (KOC) of
4-Aminophenolfor Sewage Sludge at pH 3

 

tR
[min]

k'

log k'

KOC, sewage sludge

logKOC, sewage sludge

∆ logKOC, sewage sludge

4-Aminophenol

2.568

0.127

-0.8962

6.97×10-2

-1.157

0.02

2.566

0.126

-0.8996

6.64×10-2

-1.178

2.565

0.126

-0.8996

6.64×10-2

-1.178

Mean

2.566

0.126

-0.8995

6.75×10-2

-1.17

 

SD

0.000

0.001

0.0020

1.91×10-3

0.01

CI 95%

 

-2.93 to 0.59

 

 

tR= Retention time; SD = Standard deviation; CI = Confidence Interval

Validity criteria fulfilled:
yes
Conclusions:
The estimated values of log KOC and KOC for pH 7 (undissociated form):Soil- log KOC 0.59, Sewage Sludge log KOC 0.51. According to the Mc Call classification scheme the undissociated form of the test item is classified as very high mobile in soil.

The estimated values of log KOC and KOC for pH 3 (dissociated form):Soil- log KOC -127, Sewage Sludge log KOC -1.17 . According to the Mc Call classification scheme the dissociated form of the test item is classified as very high mobile in soil.

Description of key information

log Koc=0.59 for soil and log Koc=0.51 for sewage sludge for pH 7 (undissociated form). 

Key value for chemical safety assessment

Koc at 20 °C:
3.85

Other adsorption coefficients

Type:
log Kp (solids-water in effluent sewage sludge)
Value in L/kg:
0.51

Additional information

From a key study the substance has a log Koc of 0.59 for soil and log Koc of 0.51 for sewage sludge at a pH of 7 (undissociated form). These findings indicate that it is unlikely that this substance will significantly adsorb to sediments and soils.