3-(dimethylamino)propylurea

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

!4 January - 19 January 2022

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

2004

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC method

Remarks:

The test was performed with a concentration of 5 g/L in 25% methanol : 75% water. Samples of the test item were analyzed via HPLC on a C18 column with diode array detection.

Partition coefficient type:

octanol-water

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source (i.e. manufacturer or supplier) and lot/batch number of test material: Manufacturer, UA21412002
- Purity, including information on contaminants, isomers, etc.: Content: 75% 3-(N,N-Dimethyl)propyl-urea and 25% Polyethylenglycol

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Store container tightly closed at a well-ventilated place. Store in the original container. Do not store with acids.

Analytical method:

high-performance liquid chromatography

Type:

log Pow

Partition coefficient:

0.784

Temp.:

23.6 °C

Remarks on result:

other: pH not reported

Details on results:

Two individual log POW values were derived under consideration of the first and second calibration. Finally, a mean value was calculated from these individual log POW values.
6.4 Calibration

The retention time data of the reference items used for calibration are given in Table 4

Temperature: The column temperature was measured by a data logger with an interval of 2 minutes.

6.1 Signal-to-Noise

The signal-to-noise ratio for the void time marker, reference items and the test item was > 3.


The mean temperature, based on the temperature values obtained during the experimental phase, was within the range of 20 – 25 °C ± 1 °C during the course of the study.

Type and Frequency of Measurement: Anaxlsis of the test item was carried out by HPLC_DAD with a C18 analytical column. The test item and the reference items were diluted with methanol and water to the mobile phase ration and injected into HPLC system, where the items interact with the stationary phase while passing through the column. The column temperature was monitored with a data logger during the test.

EVALUATION
Calibration of themethod was done by determination of the retention times tR of the reference items (minimum of six items). Eahc reference item was analysed separately once before and after the test item. The retention time was described by the capacity factor K given by the expression: k= tR-t0/t0

Calculation of log POW: By linear regression of the log POW of the reference items against the log k of the reference items, the equation for two calibration graphs were obtained. The n octanol / water partition coefficient for the test item was calculated by experimentally determining its capacity factor k and inserting k into the following equation obtained from the calibration graphs: log P0w= a*log k+b
a= slope of the calibration graph
b= y-intercept of calibration graph
The partition coefficient is presented individually for each calibration and in addition as mean value.

Software : The data presented in the table are computer-generated and have been rounded for presentation. Thus, manual calcluation of results based on the data in this report mayn yield minor deviations from these figures. Calculation were carried out using the software:

Microsoft® Office Excel, MICROSOFT CORPORATION
• GraphPadPrism, GRAPHPAD SOFTWARE, INC

Table 2:       Temperature [°C]

Min	23.6
Max	23.7
Mean	23.6

Determination of the Void Time

The HPLC void time (t₀) was determined by threefold injection of a solution of 10 mg/L NaNO₃.

 

Table 3:       Void Time (t₀)

Serial no.	t0 [min]
1	0.504
2	0.510
3	0.519
Mean	0.511

Table 4:       Calibration Data of the Reference Items

Reference item	log POW	1^st Calibration			2^nd Calibration
		tR1 [min]	k	log k	tR2 [min]	k	log k
2-Butanone	0.3	2.596	4.08	0.611	2.603	4.09	0.612
4-Acetylpyridine	0.5	4.358	7.53	0.877	4.341	7.50	0.875
Aniline	0.9	5.411	9.59	0.982	4.969	8.72	0.941
Acetanilide	1.0	7.244	13.2	1.12	7.279	13.2	1.12
Benzyl alcohol	1.1	7.001	12.7	1.10	7.019	12.7	1.11
Benzonitrile	1.6	16.504	31.3	1.50	16.548	31.4	1.50
Acetophenone	1.7	21.774	41.6	1.62	21.818	41.7	1.62

t_R1             Retention time 1. Injection

t_R2             Retention time 2. Injection

k            Capacity factor reference item

log P_OW  Common logarithm of the Partition Coefficient (n-octanol / water)

The calculated slope, Y-intercept and correlation coefficient for the first and second calibration of the reference items are shown in Table 5. The correlation coefficient r for both calibrations was > 0.9.

Table 5:       Slope, Y-intercept and Correlation Coefficient of the Regression Lines

 

	1^st Calibration	2^nd Calibration
slope	1.4595	1.4432
Y-intercept	-0.6140	-0.5894
r^2	0.9690	0.9635
r	0.9844	0.9816

r             Correlation Coefficient

r²            Coefficient of determination

Table 6:       Retention Times, Capacity Factors and Partition Coefficients (Test Item Signal)

Test Item Signal	tR [min]	k	log k	log POW
				1^st Calibration	2^nd Calibration
	5.377	9.52	0.979	0.780 ± 0.04 0.671 to 0.888 (95% CI)	0.789 ± 0.05 0.672 to 0.906 (95% CI)
	4.866	8.52	0.931
Mean	5.122	9.02	0.955	0.784

Conclusions:

The partition coefficient log POW ofthe test material was determined at 23.6 °C to be: 0.784

Executive summary:

The partition coefficient (n-octanol / water) of PU-2021-971 (batch UA21412002) was determined according to OECD Guideline No. 117 (2004) and Council Regulation (EC) No. 266/2016 Method A.24 on 2022-01-19 at the test facility.
The test was performed with a concentration of 5 g/L in 25% methanol : 75% water. Samples of the test item were analyzed via HPLC on a C18 column with diode array detection.
Calibration was performed using 7 reference items with known log POW values (given by the guidelines). The reference items were measured twice, once before and once after the measurement (double injection of one replicate) of the test item. The void time of the HPLC system
was determined with sodium nitrate. 
Two individual log POW values for the test item were derived under consideration of the first and second calibration and a mean value was calculated from these individual log POW values. The partition coefficient log POW of PU-2021-971 was determined at 23.6 °C to be: 0.784

Key value for chemical safety assessment

Log Kow (Log Pow):

0.784

at the temperature of:

23.6 °C