Tar bases, coal, lutidine fraction

Surface tension

Link to relevant study record(s)

Reference

Endpoint:

surface tension

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Experimental start date: 11 January 2016, Experimental completion date: 11 January 2016

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 115 (Surface Tension of Aqueous Solutions)

Version / remarks:

1995 (harmonised ring method)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.5 (Surface Tension)

Version / remarks:

Commission Regulation (EC) No 440/2008, dated May 30, 2008

Deviations:

no

GLP compliance:

no

Remarks:

However, the study was performed in a test facility which has been certified to be in compliance with the principles of GLP.

Type of method:

OECD harmonised ring method

Surface tension:

69.7 mN/m

Temp.:

20 °C

Conc.:

1.004 g/L

Remarks on result:

other: Temperature ± 0.5 °C, pH 8.4 (both samples), concentrations 1.003 and 1.004 g/L in samples A and B, respectively

Calibration factor (Φb)

The readings, temperatures and the corresponding calibration factors for the high purity water relevant to Sample Solution A and Sample Solution B are presented in Table 3 and Table 4 respectively.

Sample solution readings

The readings, times and temperatures for Sample Solution A and Sample Solution B are presented in Table 5 and Table 6 respectively.

Surface tension	=	reading · calibration factor
Sample Solution A	=	70.0 · 0.996
	=	69.7 mN/m
Sample Solution B	=	70.0 · 0.996
	=	69.7 mN/m
Overall mean	=	69.7 mN/m
Temperature	=	20.0 ± 0.5 °C
pH of sample solution	=	Sample Solution A = 8.4
	=	Sample Solution B = 8.4

Table 1: Sample Solution A Preparation Details

Sample Preparation	Time [min]
An aliquot (0.1003 g) of test item was diluted to 100 mL with high purity water.	0 to 4
The sample solution was ultrasonicated for 5 minutes.	11 to 16
The sample solution was transferred to the measuring vessel.	17

Table 2: Sample Solution B Preparation Details

Sample Preparation	Time [min]
An aliquot (0.1004 g) of test item was diluted to 100 mL with high purity water.	0 to 5
The sample solution was ultrasonicated for 5 minutes.	6 to 11
The sample solution was transferred to the measuring vessel.	12

Table 3: Water Calibration Data Relevant to Sample Solution A

Reading [mN/m]	Temperature [°C]	Literature Value [mN/m]	Calibration Factor
73.0	20.0	72.72	0.996
73.0	20.0	72.72	0.996
73.0	20.0	72.72	0.996
73.0	20.0	72.72	0.996
73.0	20.0	72.72	0.996
73.0	20.0	72.72	0.996
Mean Calibration Factor = 0.996

Table 4: Water Calibration Data Relevant to Sample Solution B

Reading [mN/m]	Temperature [°C]	Literature Value [mN/m]	Calibration Factor
73.0	20.0	72.72	0.996
73.0	20.0	72.72	0.996
73.0	20.0	72.72	0.996
73.0	20.0	72.72	0.996
73.0	20.0	72.72	0.996
73.0	20.0	72.72	0.996
Mean Calibration Factor = 0.996

Table 5: Sample Solution A Surface Tension Measurements

Time [min]	Temperature [°C]	Reading [mN/m]
68	20.0	70.0
94	20.0	70.0
120	20.0	70.0
144	20.0	70.0
167	20.0	70.0
Mean sample reading = 70.0

Table 6: Sample Solution B Surface Tension Measurements

Time [min]	Temperature [°C]	Reading [mN/m]
81	20.0	70.0
107	20.0	70.0
132	20.0	70.0
155	20.0	70.0
179	20.0	70.0
Mean sample reading = 70.0

 

Conclusions:

In a reliable and conclusive study according to OECD TG 115 (1995) and EU Method A.5 (2008), the average surface tension of duplicate 1.0 g/L solutions of test item in water has been determined to be 69.7 mN/m at 20.0 ± 0.5 °C.

Executive summary:

The surface tension of the test item in an aqueous solution (ca. 1 g/L) was investigated in a non-GLP study using the harmonised ring method according to the OECD TG 115 (1995) and EU A.5 (Commission Regulation (EC) No 440/2008) protocols. The experiment is considered relevant, adequate and conclusive.

An aliquot of each of the two sample solutions was transferred to an individual, previously cleaned measurement vessel (time zero for sample readings) and the measuring vessels were then allowed to equilibrate for at least one hour. Each measurement vessel was placed onto the mobile sample table, which was raised until the ring was immersed below the surface of the solution. Subsequently, the table was lowered until the ring was just below that of the liquid surface. After additional lowering of the table, the ring exerted a torque on the force measuring system. Lowering of the table and subsequent compensation of the resulting torque were continued in small increments until the lamina broke. This was when the upward force completely overcame the surface tension force and the ring was released from the surface. The force required to overcome the surface tension of the liquid was recorded directly from the tensiometer.

Since the surface tension of a solution in the measurement vessel may alter over a period of time, several measurements were made until a consistent value was obtained. The time elapsed since the solution was transferred to the measurement vessel was recorded for each value. The pH of each solution was measured. The average surface tension of duplicate 1.0 g/L solutions of test item in water at pH 8.4 has been determined to be 69.7 mN/m at 20.0 ± 0.5 °C.

Description of key information

In a valid, reliable and conclusive study according to OECD TG 115 (1995) and EU Method A.5 (2008), the average surface tension of duplicate 1.0 g/L solutions of test item in water has been determined to be 69.7 mN/m at 20.0 ± 0.5 °C.

Key value for chemical safety assessment

Surface tension:

69.7

in mN/m at 20°C and concentration in mg/L:

1 000