Reaction products of tetrabromophthalic anhydride with 2,2'-oxydiethanol and methyloxirane

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13 APR 2021 - XX JUN 2022

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7570 (Partition Coefficient, n-octanol / H2O, Estimation by Liquid Chromatography)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient - HPLC Method)

Version / remarks:

92/69/EEC. 1992. Partition Coefficient. Official Journal of the European Communities No. L383

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)

Version / remarks:

Adopted 13 April 2004

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Type:

log Pow

Partition coefficient:

< 1

Temp.:

40 °C

Remarks on result:

other: volatile low molecular impurities

Type:

log Pow

Partition coefficient:

ca. 3 - ca. 5

Temp.:

40 °C

Remarks on result:

other: monomers

Type:

log Pow

Partition coefficient:

> 6.5

Temp.:

40 °C

Remarks on result:

other: Di- and Trimers

A total of eight reference substances were prepared and injected in duplicate (once near the beginning and once near the end of the HPLC sequence).  The retention times for one of the reference substances, thiourea, was used to determine the analytical column dead time (t₀) for use in calculating capacity factors (k) of the remaining reference substances and the test substance.  The mean retention time of thiourea was 1.635 minutes on the UV detector.

Seven additional reference substances were analyzed. The capacity factors of all the reference substances were calculated based upon their retention times on the UV detector.

Prior to the initial injection of the reference standards, an injection of the first reagent blank solution (75%:25% MeOH: GenPure water, v/v) showed that the reagents used were free of any contaminants, that would impact the final results of the study, and confirmed the peak retention assignments for the reference substances. Two peaks were detected in every reference standard injection. These peaks were most likely attributed to instrument and/or solvent contamination as the peaks were present in every standard injection and confirmed by the reagent blank injections.  The peaks did not have any impact on the results of the study.  A representative chromatogram of the first reagent blank solution is presented in Figure 2.  Prior to the initial injection of the test substance samples, an injection of the second blank solution (70%:20%:10% MeOH: GenPure water: acetone, v/v) and an injection of the third blank solution (65%:15%:20% MeOH: GenPure water: acetone, v/v) showed the reagents used were free of any contaminants, that would impact the final results of the study, and assisted in confirming the peak retention assignments for the test substance.  The reagent blank injections resulted in a total of 2 to 5 peaks that were detected in every test substance sample.  These peaks were most likely attributed to the solvents and reagents used as well as the gradient profile.

The three 0.501 mg/mL test substance solutions and the high-level test substance solution, 1.00 mg/mL, preparation were sequentially injected on the HPLC/UV.  The Saytex RB-79 test substance reproducibly eluted as twenty-four peaks on the UV detector as confirmed by the high-level injection.  The mean retention times of each UV peak ranged from 1.516 minutes to 52.175 minutes.  One peak (peak 1) eluted prior to the retention time for thiourea and could be represent low molecular weight impurities of the test item (see GLP characterization).  Therefore, the non-retained peak is associated with a calculated negative capacity factor and a corresponding log P_OW could not be extrapolated.  The log Pow of the test substance peak is therefore reported as less than the log Pow for thiourea (i.e., < -1.02) (6).  One peak (peak 2) eluted prior to the retention time for acetanilide.  Therefore, the corresponding log P_OW could not be extrapolated.  The log Pow of the test substance peak is therefore reported as less than the log Pow for acetanilide (i.e., < 1.0) (6).  Thirteen peaks eluted prior to the retention time for 4,4’-DDT.  The calculated mean retention time for test substance peaks 3 through 15 are 4.362, 4.881, 5.277, 5.526, 5.958, 6.137, 6.395, 7.036, 7.495, 7.959, 9.025, 27.141, and 32.124 minutes, respectively.  The corresponding Log P_OW for these test substances peaks were 3.12, 3.34, 3.48, 3.56, 3.69, 3.74, 3.81, 3.96, 4.06, 4.16, 4.35, 5.87, and 6.09, respectively. Test substance peaks 16 through 24 were forced off the column using a gradient.  Therefore, the log P_OW for peaks 16 through 24 are extrapolated and are greater than the latest eluting reference standard, 4,4’-DDT (Log P_OW = 6.5). Test substance peak assignments were based on three factors:  the peaks present in the reagent blanks as discussed above, the peaks that displayed the proportional increase or decrease in area in relation to the test substance stock concentration, and the peaks that resulted in area % greater than 0.1%.

The three 251 µg/L test substance solutions and the low-level test substance solution, 100 µg/L, preparation were sequentially injected on the LC/MS/MS.  The test substance reproducibly eluted as four peaks on the LC/MS/MS detector as confirmed by the low level, total ion chromatogram, and the specific mass spectrum transitions for the mono/di and trimers.  The monomers  eluted at approximately 5.8 minutes and 6.2 minutes.  The dimers eluted at approximately 47.8 minutes.  The trimers eluted at approximately 51.3 minutes.

Conclusions:

Under the chromatographic conditions specified, the test substance eluted as twenty-four peaks on the UV detector. The log Pow for the test substance is ranged from < 1.0 (most likely reflecting volatile low molecular impurities) to > 6.50. For monomers low POWs in the range of 3-5 and for Di and Trimers in the range > 6.5 Under the chromatographic conditions specified, the test substance eluted as four peaks on the LC/MS/MS detector. The retention times correspond to the specific oligomers which were directly compared to the peaks in the HPLC/UV sequence.

Executive summary:

A study was performed to estimate the n-octanol/water partition coefficient of the test substance a UVCB compound.

The test was performed according to OECD Guideline 117,  U.S. EPA Product Properties Test Guidelines OPPTS 830.7570 and EU method A.8 under GLP.

Under the chromatographic conditions specified, the test substance eluted as twenty-four peaks on the UV detector. The log Pow for the test substance is ranged from < 1.0 (most likely reflecting volatile low molecular impurities) to > 6.50. For monomers low POWs in the range of 3-5 and for Di and Trimers in the range > 6.5 Under the chromatographic conditions specified, the test substance eluted as four peaks on the LC/MS/MS detector. The retention times correspond to the specific oligomers which were directly compared to the peaks in the HPLC/UV sequence.

Description of key information

A study was performed to estimate the n-octanol/water partition coefficient of the test substance a UVCB compound.

The test was performed according to OECD Guideline 117,  U.S. EPA Product Properties Test Guidelines OPPTS 830.7570 and EU method A.8 under GLP.

Under the chromatographic conditions specified, the test substance eluted as twenty-four peaks on the UV detector. The log Pow for the test substance is ranged from < 1.0 (most likely reflecting volatile low molecular impurities) to > 6.50. For monomers low POWs in the range of 3-5 and for Di and Trimers in the range > 6.5 Under the chromatographic conditions specified, the test substance eluted as four peaks on the LC/MS/MS detector. The retention times correspond to the specific oligomers which were directly compared to the peaks in the HPLC/UV sequence.