No IUPAC name is currently defined for Cashew (Anacardium occidentale) Nutshell Extract, Decarboxylated, Distilled (“Distilled Residue Grade”).

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

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))

GLP compliance:

yes

Type of method:

HPLC estimation method

Media:

soil

Details on study design: HPLC method:

A liquid chromatograph, comprising a pulse-free pump, injection valve with injection loopand suitable detector, was used in conjunction with a commercially available analyticalcolumn packed with a solid phase containing a moderately polar stationary phase withlipophilic and polar moieties (e.g. cyano-propyl bonded phase)., The followingmobile phases were used :methanol/water (55/45% v/v)- methanol/0.01M citrate-buffer pH 6.0 (55/45% v/v)HPLC grade methanol and distilled water were used to prepare the eluting solvent. Themobile phase was degassed before use. If methanol/water mixtures were not appropriate,other organic solvent/water mixtures were be tried, e.g. ethanol/water or acetonitrile/watermixtures.Measurements were made on ionisable substances at selected pH values by appropriatebuffering of the HPLC eluent.Isocratic elutions were employed and the temperature during the measurements wasrecorded...A minimum of 6 standard reference compounds were injected and the retention timesdeterminedAt least one standard was above and one below the expectedvalue of the test substance. Chemicals injected onto the column move along it by partitioningbetween the mobile phase and the stationary phase. The velocity of each component therebydepends on the degree of adsorption on the stationary phase. The dual nature of the stationaryphase allows for interaction of polar and apolar parts of a molecule in a similar way as is thecase for soil. This enables the relationship between the retention time on such a column andthe adsorption coefficient on the organic parts of the soil to be established. The capacityfactor, k, was determined for reference compounds from the expression:k = (tr - t0)/t0where tr is the retention time of the compound and t0 is the deadtime, i.e. the average time asolvent molecule needs to pass through the column. The deadtime was obtained using anunretained molecule, e.g. formamide, urea, thiourea or sodium nitrate.The corresponding logarithms of the capacity factors, log10k, were calculated and plotted asa function of log10Koc. The retention time of the test substance was determined in duplicate,and log10Koc calculated by interpolation of the calculated capacity factor on the calibrationgraph.For very low and very high adsorption coefficients, extrapolation was necessary.Especially in these cases, care has been taken concerning the confidence limits of theregression curve and the validity of the extrapolation.

Type:

log Koc

Value:

4.4 - 5.7

Details on results (HPLC method):

Soil adsorption: a log10Koc range of 4.4 to 5.7 was determined for the main components of the test substance.

A calibration plot of log₁₀k versus log₁₀K_ocwas constructed for the reference standards. The logarithms of the capacity factors for the test substance were then calculated and the log₁₀K_ocvalues were determined by interpolation (Table 1).

The main components of the test substance were found to have log₁₀K_ocvalues between 4.4 and 5.7.

Table 1         HPLC determination of log₁₀K_oc 

 

Sample	Component	tr(minutes)	k	log10k	log10Koc
Standard Run A	Acetanilide	3.354	0.208	-0.681	1.3
(t0= 2.776 minutes)	Nitrobenzene	4.069	0.466	-0.332	2.4
	Naphthalene	4.723	0.701	-0.154	2.8
	2-Methylnaphthalene	5.008	0.804	-0.095	3.9
	Anthracene	5.563	1.004	0.002	4.4
	DDT	8.086	1.913	0.282	5.6
Sample A	Test substance	5.902 - 8.621	1.123 - 2.101	0.050 - 0.322	4.4 - 5.7
(t0= 2.780 minutes)
Sample B	Test substance	5.901 - 8.620	1.123 - 2.101	0.050 - 0.322	4.4 - 5.7
(t0= 2.780 minutes)
Standard Run B	Acetanilide	3.355	0.208	-0.682	1.3
(t0= 2.777 minutes)	Nitrobenzene	4.070	0.466	-0.332	2.4
	Naphthalene	4.724	0.701	-0.154	2.8
	2-Methylnaphthalene	5.009	0.804	-0.095	3.9
	Anthracene	5.564	1.004	0.002	4.4
	DDT	8.086	1.912	0.281	5.6

 

Linear regression (based on mean of standard runs A and B): log₁₀K_oc= 4.70 log₁₀k + 4.14

Executive summary:

Soil adsorption: a log10Koc range of 4.4 to 5.7 was determined for the main components of the test substance.

Key value for chemical safety assessment

Koc at 20 °C:

125 892.5

Additional information

Soil adsorption: a log10Koc range of 4.4 to 5.7 was determined for the main components of the test substance.