Potassium isooctadecanoate

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:

2017

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))

Deviations:

no

Qualifier:

equivalent or similar 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

Remarks:

Study conducted under GLP like conditions.

Type of method:

HPLC estimation method

Media:

other: Matrix: commercially available cyanopropyl solid phase containing lipophilic and polar moieties, Eluent: 0.01 M citrate buffer pH6 / methanol (45 : 55 (v/v))

Specific details on test material used for the study:

Product description: Potassium isooctadecanoate/potassium isostearate
Name: Isooctadecanoic acid, potassium salt
CAS No.: 66469-15-6
Physical state: off white to yellowish solid at 20 °C
Batch No.: PFS-755-169
Re-certification date of batch: 12 December 2017
Purity: 100 % (UVCB)
pH, 10% in DI water 8.0 - 9.0
Stability: stable under test conditions
Storage condition of test material: Room temperature, protected from light

Radiolabelling:

no

Test temperature:

40 °C

Details on study design: HPLC method:

HPLC conditions

Column: Lichrospher 100 CN, 250 x 4 mm, 5 µm
Column temperature: 40 °C
Eluent: 0.01 M citrate buffer pH6 / methanol (45 : 55 (v/v))
Injection volume: 50 µl
Detector: RI detector (Tem. = 40 °C, SR2, Sens. 64)

Key result

Sample No.:

#1

Type:

log Koc

Value:

0.6 dimensionless

pH:

6

Temp.:

40 °C

Matrix:

commercially available cyanopropyl solid phase containing lipophilic and polar moieties

By analysis of the reference items via HPLC the corresponding retention times can be determined.

The retnetion time of sodium nitrate is taken as dead time t(0), and the retention times of other reference items t(r) are corrected by subtracting the dead time. The capacity factor k' is calculated for each reference item.

k' = (t(r) - t(0)) / t(0)

By relating logk' to the corresponding log Koc values (known from literature) calibration curves can be set up.

The results obtained for the references are summarised below.

Reference items

Reference item	t(r) [min]	t(r) [min]	t(r) mean [min]	capacity factor k'	log k'	log Koc
Sodium nitrate	2.412	2.405	2.409
Acetanilid	3.391	3.387	3.389	0.407	-0.390	1.25
Phenol	3.374	3.376	3.375	0.401	-0.397	1.32
Methylbenzoate	3.764	3.762	3.763	0.562	-0.250	1.80
Linuron	4.675	4.672	4.674	0.940	-0.027	2.59
Naphthalene	5.102	5.100	5.101	1.118	0.048	2.75
Phenantrene	7.295	7.292	7.294	2.028	0.307	4.09

Results of the test item

	t(r) sample 1 [min]	t(r) sample 2 [min]	t(r) mean [min]	Capacity factor k'	log k'	log Koc
test item	3.078 / 3.076	3.073 / 3.081	3.077	0.278	-0.557	0.61

A retention time of 3.077 min was determined for the test item. The log Koc can be reported as: 0.61.

Validity criteria fulfilled:

yes

Conclusions:

A retention time of 3.077 min was determined for the test item. The log Koc can be reported as: 0.61.

Executive summary:

In an OECD 121 study a retention time of 3.077 min was determined for the test item. The log Koc can be reported as: 0.61.

Description of key information

A retention time of 3.077 min was determined for the test item. The log Koc can be reported as: 0.61.

Key value for chemical safety assessment

Koc at 20 °C:

4.07

Additional information

[LogKoc: 0.61]