Phenol, heptyl derivs.

Adsorption / desorption

Administrative data

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Testing was conducted between 08 December 2011 and 24 April 2012.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results. The study report was conclusive, done to a valid guideline and the study was conducted under GLP conditions.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

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:

Phenol, heptyl derivs.

EC Number:

276-743-1

EC Name:

Phenol, heptyl derivs.

Cas Number:

72624-02-3

Molecular formula:

C13H20O

IUPAC Name:

4-(2-methylhexyl)phenol; 4-heptylphenol

Details on test material:

Description: amber coloured viscous liquid
Purity: 100% (based on UVCB composition)
Expiry date: 01 December 2012
Date received: 01 December 2011
Storage conditions: room temperature, in the dark

Radiolabelling:

no

Study design

HPLC method

Details on study design: HPLC method:

Procedure
Preparation of sample solution
Test item (0.1017 g) was diluted to 100 ml with methanol.
Preparation of dead time solution
The dead time was determined by measuring the retention time of formamide (purity* 99.94%, 626 mg/l solution in mobile phase).
Preparation of reference standard solutions
Solutions of reference standards (see table 10.1 - in any other information on material and methods section of this summary) were prepared in methanol.

Determination of retention time
The sample, dead time and reference standard solutions were injected in duplicate using the following HPLC parameters:
HPLC System : Agilent Technologies 1100, incorporating autosampler and workstation
Column : Luna 5µ CN (150 x 4.6 mm id)
Column temperature: 40ºC
Mobile phase : methanol: water (55:45 v/v)
pH of mobile phase: 7.0
Flow-rate : 1.0 ml/min
Injection volume: 10 µl
UV detector wavelength : dead time and reference standards: 210 nm
sample: 223 nm


Construction of calibration curve
A calibration curve was constructed from the retention time data of the dead time and reference standard solutions (Figure 10.1 - Attachment 1 of this Summary). The capacity factors (k) for the reference standards were calculated using Equation 10.1 - (Please see any other information on materials and methods section of this summary).

Adsorption coefficient of sample
The capacity factor was calculated using Equation 10.1 and the log10 Koc value determined using Equation 10.2 - (Please see below in any other information on materials and methods section of this summary) with reference to the calibration curve (Figure 10.1 - Attachment 1 of this Summary).

Please see Attachment 2 for Typical Chromatography.

Batch equilibrium or other method

Analytical monitoring:

no

Results and discussion

Adsorption coefficient

Adsorption coefficient 1

Type:

Koc

Value:

>= 91.8 - <= 5 790

Remarks on result:

other: Adsorption coefficient range 91.8 to 5790

Adsorption coefficient 2

Type:

log Koc

Value:

>= 1.96 - <= 3.76

Remarks on result:

other: Overall log10 Koc range: 1.96 to 3.76

Results: Batch equilibrium or other method

Transformation products:

not measured

Details on results (Batch equilibrium method):

In this case Not applicable.

Any other information on results incl. tables

Results

Calibration

The retention times of formamide and the retention times, capacity factors (k) and log₁₀ K_ocvalues for the reference standards are shown in the two following tables:

Table 10.2

Dead Time	Retention Time (mins)		Mean Retention Time (mins)
	Injection 1	Injection 2
Formamide	1.973	1.973	1.973

 

Table 10.3

Standard	Retention Time (mins)		Mean Retention Time (mins)	Capacity Factor (k)	Log10k	Log10Koc
	Injection 1	Injection 2
Acetanilide	2.677	2.677	2.677	0.356	-4.48E-01	1.25
Phenol	2.583	2.583	2.583	0.309	-5.10E-01	1.32
Atrazine	3.653	3.653	3.653	0.851	-6.99E-02	1.81
Isoproturon	3.923	3.923	3.923	0.988	-5.17E-03	1.86
Triadimenol	5.320	5.327	5.323	1.698	2.30E-01	2.40
Linuron	5.557	5.550	5.553	1.814	2.59E-01	2.59
Naphthalene	4.817	4.810	4.813	1.439	1.58E-01	2.75
Endosulfan-diol	6.977	7.010	6.993	2.544	4.06E-01	3.02
Fenthion	8.190	8.180	8.185	3.148	4.98E-01	3.31
a-Endosulfan	12.000	11.943	11.972	5.067	7.05E-01	4.09
Diclofop-methyl	12.570	12.580	12.575	5.372	7.30E-01	4.20
Phenanthrene	9.110	9.100	9.105	3.614	5.58E-01	4.09
DDT	25.357	25.293	25.325	11.834	1.07E+00	5.63

 

Adsorption coefficient of sample

The retention times, capacity factors and log₁₀K_ocvalues determined for the sample are shown in the following table:

Table 10.4

Peak Number	Retention Time (mins)			Capacity Factor (k)	Log10k	Log10Koc
	Injection 1	Injection 2	Mean
1	3.687	3.673	3.680	0.865	-6.31E-02	1.96
2	4.073	4.073	4.073	1.064	2.70E-02	2.23
3	4.823	4.817	4.82	1.443	1.59E-01	2.61
4	5.84	5.833	5.837	1.958	2.92E-01	3.00
5	7.243	7.233	7.238	2.668	4.26E-01	3.39
6	8.02	8.017	8.018	3.063	4.86E-01	3.56
7	8.66	8.647	8.653	3.385	5.30E-01	3.69
8	9.077	9.063	9.070	3.596	5.56E-01	3.76

Overall log₁₀K_ocrange:                  1.96 to 3.76
Adsorption coefficient range:       91.8 to 5.79 x 10³

Percentage area normalisation data for the two injections of the test item sample solution is shown in the following table:

Table 10.5

Peak Number	Percentage of Total Area (%)
	Injection 1	Injection 2	Mean
1	0.02	0.02	0.02
2	0.48	0.48	0.48
3	0.06	0.06	0.06
4	2.37	2.37	2.37
5	90.0	90.0	90.0
6	1.38	1.38	1.38
7	3.92	3.93	3.93
8	1.78	1.78	1.78

 

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The adsorption coefficient (Koc) of the test item has been determined to be within the range 91.8 to 5790, log10 Koc 1.96 to 3.76. The dominant component of the test item (90.0% by percentage area normalisation) resulted in an adsorption coefficient value of 2.43 x 103, log10 Koc 3.39.

Executive summary:

Method

The determination was carried out using a HPLC screening method, designed to be compatible with Method C19 Adsorption Coefficient ofCommissionRegulation (EC) No 440/2008 of 30 May 2008 and Method 121 of the OECD Guidelines for Testing of Chemicals, 22 January 2001.

Discussion

The method guideline states that the measurement of adsorption coefficient should be carried out on substances in their ionised and unionised forms. However, the dissociation constants of certain functional groups found in the test item made it impossible to satisfy this criteria. 

From structural information supplied by the Sponsor, estimations of the phenol functional group dissociation constants of 10.3 to 11.8 were generated using predictive computer modelling (SPARC version 4.6,October 2011, w4.6.1691-s4.6.1687).

Therefore, formation of the ionised form of the test item would only occur under basic conditions (pH >8). As such pH’s are not environmentally relevant, only a single determination was performed at an approximately neutral pH.

Conclusion

The adsorption coefficient (K_oc) of the test item has been determined to be within the range 91.8 to 5.79 x 10³, log₁₀K_oc 1.96 to 3.76. The dominant component of the test item (90.0% by percentage area normalisation) resulted in an adsorption coefficient value of 2.43 x 10³, log₁₀K_oc 3.39.