Bis-O-(benzylidene)-D-glucitol

Adsorption / desorption

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1 September 1997 to 26 November 1997

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study.

Qualifier:

according to guideline

Guideline:

other: OECD draft guideline (July 1997): Screening Method for the Determination of the Adsorption Coefficient (Koc) on Soil and Sewage Sludge using High Performance Liquid Chromatography (HPLC).

Deviations:

no

Qualifier:

equivalent or similar 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 (incl. QA statement)

Type of method:

HPLC estimation method

Media:

soil/sewage sludge

Test temperature:

30°C (HPLC column temperature).

Details on study design: HPLC method:

See any other information on materials and methods section.

Type:

log Koc

Value:

2.96 dimensionless

Temp.:

30 °C

Details on results (HPLC method):

See any other information on results section.

Results

Calibration

The retention times of formamide and the reference standards are shown in attached background material.

The capacity factor (k) and log₁₀ K_oc values for the reference standards and calibration curve are shown in attached background material.

Adsorption coefficient of sample

The retention times, capacity factors and log₁₀ K_oc values determined for the sample for shown in the table below.

Injection	Retention time (mins)	Capacity factor (k)	Log10 k	Log10 Koc
1	6.294	0.900	-4.600 x 10^-2	2.96
2	6.284	0.896	-4.746 x 10^-2	2.96

Overall log₁₀K_oc : 2.96

Adsorption coefficient: 907

Validity criteria fulfilled:

yes

Conclusions:

The adsorption coefficient of the test material was determined to be 907, log Koc 2.96.

Executive summary:

The adsorption coefficient for the test material was assessed according to OECD draft guideline (July 1997): Screening Method for the Determination of the Adsorption Coefficient (Koc) on Soil and Sewage Sludge using High Performance Liquid Chromatography (HPLC).

The adsorption coefficient was determined to be 907, log Koc 2.96.

Reference 2

Endpoint:

adsorption / desorption: screening

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Please see Section 13 for "Read-across justification to support the REACH registration of Bis-O-(benzylidene)-D-glucitol (EC 251-136-4) at 10-100 tpa" for full details.

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
It is proposed that the structural similarity and properties of the target substance and the structural analogue (sources substance) are sufficiently close for there to be a reasonable expectation of similar effects.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Source substance:
IUPAC name: 1,3:2,4-bis-O-((3,4-dimethylphenyl)methylene) D-Glucitol
EC number: 413-110-2
CAS number: 135861-56-2


Target Substance: Bis-O-(benzylidene)-D-glucitol
IUPAC name: 1,3:2,4-bis-O-dibenzylidene-D-glucitol
EC number: 251-136-4
CAS number: 32647-67-9


3. ANALOGUE APPROACH JUSTIFICATION
Based on the structural similarity of the source substances and target substance, similarity of physic-chemical properties and similarity in experimental (eco)toxicological test data (and toxicokinetic behaviour assessment) it is concluded that target substance and the structural analogue (source substance) are sufficiently close for there to be a reasonable expectation of similar effects, for the endpoints where results have been read-across.

4. DATA MATRIX
Please see Section 13 for "Read-across justification to support the REACH registration of Bis-O-(benzylidene)-D-glucitol (EC 251-136-4) at 10-100 tpa" for full details.

Reason / purpose for cross-reference:

read-across source

Type:

log Koc

Value:

2.96 dimensionless

Temp.:

30 °C

Validity criteria fulfilled:

yes

Conclusions:

The adsorption coefficient was determined to be 907, log Koc 2.96.

Executive summary:

The adsorption coefficient for the test material (structural analgoue EC 413-110-2) was assessed according to OECD draft guideline (July 1997): Screening Method for the Determination of the Adsorption Coefficient (Koc) on Soil and Sewage Sludge using High Performance Liquid Chromatography (HPLC).

The adsorption coefficient was determined to be 907, log Koc 2.96.

Reference 3

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

between 4th October and 11th October 2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: 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 relevant results.

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:

not specified

Test temperature:

30 deg C

Details on study design: HPLC method:

Procedure:
Preparation of sample solution:
Test material (0.01 g) was diluted to 100 ml with methanol.

Preparation of reference solutions
The dead time was determined by measuring the retention time of formamide (purity* >99.5%, 1 x 103 mg/l solution in methanol).

The sample, formamide and reference standard solutions were injected in duplicate using the following HPLC parameters:

HPLC System : Agilent Technologies 1100, incorporating autosampler and workstation
Column : Zorbax SB-CN 5µm (250 x 4.6 mm id)
Column temperature: 30ºC
Mobile phase : methanol:water (55:45 v/v)
pH of mobile phase: 6.61
Flow rate : 1 ml/min
UV detector wavelength : dead time and reference standards: 210 nm, sample: 210 nm
Injection volume: 10 µl

A calibration curve was constructed from the retention time data of the formamide and reference standard solutions. The capacity factors (k) for the reference standards were calculated using equation 1.

The capacity factor was calculated using Equation 1 and the log10Koc value determined with reference to the calibration curve.

Equation 1: k = tr - t0 / to
where:
K = capacity factor
tr = retention time (min)
t0 = dead time (min)

Type:

log Koc

Value:

2.47 dimensionless

Temp.:

30 °C

Type:

Koc

Value:

296 L/kg

Temp.:

30 °C

Table of results:

Injection	Retention Time (mins)	Capacity Factor (k)	Log10k	Log10Koc
1	8.022	1.837	0.264	2.470
2	8.026	1.839	0.264	2.471

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 material made it impossible to satisfy this criterion. Testing would be required at greater than pH 14 to obtain the test material in its ionised form. As a consequence of this, the functional groups will always be present in their unionised forms. Therefore, as pH 14 or above is outside the environmental pH range for this test and also experimentally impractical, testing was carried out at approximately neutral pH with the functional group unionised (the predicted values of pKa were obtained using the ACD/I-Lab Web Service (ACD/pKa 8.03)).

Validity criteria fulfilled:

yes

Conclusions:

The adsorption coefficient (Koc) of the test material has been determined to be 296, log10 Koc 2.47.

Executive summary:

Adsorption Coefficient: 

A Koc of 296 and a log₁₀K_oc of 2.47 was determined for the test material, using the HPLC screening method, Method C19 of Commission Directive 2001/59/EC.

Reference 4

Endpoint:

adsorption / desorption: screening

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Please see Section 13 for "Read-across justification to support the REACH registration of Bis-O-(benzylidene)-D-glucitol (EC 251-136-4) at 10-100 tpa" for full details.

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
It is proposed that the structural similarity and properties of the target substance and the structural analogue (sources substance) are sufficiently close for there to be a reasonable expectation of similar effects.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Source substance:
IUPAC name: 1-(2,6-bis(4-tolyl)-1,3-dioxano(5,4-d)-1,3-dioxan-4-yl)ethane-1,2-diol
EC number: 402-950-5
CAS number: 87826-41-3

Target Substance: Bis-O-(benzylidene)-D-glucitol
IUPAC name: 1,3:2,4-bis-O-dibenzylidene-D-glucitol
EC number: 251-136-4
CAS number: 32647-67-9


3. ANALOGUE APPROACH JUSTIFICATION
Based on the structural similarity of the source substances and target substance, similarity of physic-chemical properties and similarity in experimental (eco)toxicological test data (and toxicokinetic behaviour assessment) it is concluded that target substance and the structural analogue (source substance) are sufficiently close for there to be a reasonable expectation of similar effects, for the endpoints where results have been read-across.

4. DATA MATRIX
Please see Section 13 for "Read-across justification to support the REACH registration of Bis-O-(benzylidene)-D-glucitol (EC 251-136-4) at 10-100 tpa" for full details.

Reason / purpose for cross-reference:

read-across source

Type:

log Koc

Value:

2.47

Temp.:

30 °C

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 material made it impossible to satisfy this criterion. Testing would be required at greater than pH 14 to obtain the test material in its ionised form. As a consequence of this, the functional groups will always be present in their unionised forms. Therefore, as pH 14 or above is outside the environmental pH range for this test and also experimentally impractical, testing was carried out at approximately neutral pH with the functional group unionised (the predicted values of pKa were obtained using the ACD/I-Lab Web Service (ACD/pKa 8.03)).

Validity criteria fulfilled:

yes

Conclusions:

The adsorption coefficient (Koc) of the test material has been determined to be 296, log10 Koc 2.47.

Executive summary:

A Koc of 296 and a log₁₀K_oc of 2.47 was determined for the test material (structural analgoue EC 402-950-5), using the HPLC screening method, Method C19 of Commission Directive 2001/59/EC.

Reference 5

Endpoint:

adsorption / desorption: screening

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Study period:

Not applicable

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

results derived from a (Q)SAR model, with limited documentation / justification

Justification for type of information:

A QSAR predicition for adsorption coefficient (log Koc) was made using EPI Suite model KOCWIN (v2.00)

Qualifier:

no guideline followed

Principles of method if other than guideline:

A QSAR predicition for adsorption coefficient (log Koc) was made using EPI Suite model KOCWIN (v2.00)

GLP compliance:

no

Type:

log Koc

Value:

>= 0.93 - <= 1.12 dimensionless

Remarks on result:

other: QSAR prediction results

KOCWIN v2.00 gave the following results for the substance (where substance log Kow was identified as 2.16).

Koc estimate from MCI:

Corrected Log Koc: 1.1285

Koc estimate from Log Kow:

Corrected Log Koc: 0.9346

Validity criteria fulfilled:

not applicable

Conclusions:

KOCWIN v2.00 gave predictions for the substance log Koc as 1.1285 (MCI method) and 0.9346 (from Log Kow).

Description of key information

An adsorption/desorption screening test was not conducted on the target substance (EC 251-136-4), as based on the substances physico-chemical properties (especially octanol/water partition coefficient of log Kow 2.16) the substance is expected to have low potential for adsorption.

However, to confirm this low potential for adsorption the substance (EC 251-136-4) has been assessed by reading across the results of adsorption/desorption screening studies conducted on two structurally similar analogue substances, which are detailed below.

Source Substance; (EC-413 -110 -2):

The adsorption coefficient was determined to be 907, log Koc 2.96.

Source Substance; Gel All MD (EC 402-950-5):

The adsorption coefficient (Koc) of the test material has been determined to be 296, log10 Koc 2.47.

These results were supported by a basic QSAR prediction for log Koc, run using EPI Suite model KOCWIN (v2.00).

KOCWIN v2.00 gave predictions for the substance log Koc as 1.1285 (MCI method) and 0.9346 (from Log Kow).

Additional information

Based on the target substances log Kow, log Koc results from two structurally similar analogue substances and a QSAR prediction on the target substance, it is considered that the substance has a low potential for adsorption.