2-[[4-[ethyl(2-hydroxyethyl)amino]phenyl]azo]-6-methoxy-3-methylbenzothiazolium chloride

Surface tension

Link to relevant study record(s)

Reference

Endpoint:

surface tension

Type of information:

experimental study

Adequacy of study:

key study

Study period:

August 30, 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 115 (Surface Tension of Aqueous Solutions)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.5 (Surface Tension)

Deviations:

no

GLP compliance:

no

Type of method:

ring method

Key result

Surface tension:

52.7 mN/m

Temp.:

20 °C

Conc.:

1 000 mg/L

An aqueous solution of the test item in de-ionized water with a concentration of 1000.0 mg/L was prepared. After adapting to 20 °C the measurement of the surface tension with the test item was carried out at 20 ±0.5°C (20.0 °C), as follows:

The solution to be measured was transferred to the measurement vessel, taking care to avoid foaming. The measurement vessel was placed on the table of the test apparatus. The measurement vessel was raised until the ring was immersed below the surface of the solution. The time from starting the measurement was recorded (see Table1 below). Subsequently, the table top was lowered gradually and evenly at a rate of 0.3 cm/min to detach the ring from the surface until the maximum force was reached. The force was read on the tensiometer. The measurements were repeated until 6 measurements were within the limits of the stability criterion.

Table1: Surface tension

Measurement	1	2	3	4	5	6
Time (s)	97	158	218	279	340	401
σ (mN/m) uncorrected	58.17	58.04	57.98	58.04	57.98	57.94
σ (mN/m) corrected according to Zuidema and Waters[1]	52.86	52.73	52.68	52.73	52.68	52.64

Mean value:    σ= 52.7 mN/m (corrected according to Zuidema and Waters¹)

The aqueous solution of the test item had a mean surface tension of 52.7 mN/m. As the surface tension was lower than 60 mN/m, the test item had surface-active properties.

[1]Zuidema, H., Waters, C.W.,Ind. Eng.Chem. Analyt.13 (1941), S. 312

Conclusions:

The surface tension of the aqueous solution at 20 °C had a mean value of 52.7 mN/m. The test item had surface-active properties.

Executive summary:

The surface tension was measured according to OECD 115, based on the measurement of the maximum vertical force, which is necessary to separate a ring being in contact with the liquid filled in a measuring cup from the surface of this liquid. A solution of the substance (1000.o mg/L) was prepared in de-ionized water, adapted to 20°C and carefully filled into the measurement vessel to avoid foaming. Once the measurement vessel was raised until the ring was immersed below the surface of the solution, the table top was lowered gradually and evenly at a rate of 0.3 cm/min to detach the ring from the surface until the maximum force was reached. The force was read on the tensiometer and corrected automatically according to Zuidema and Waters.

The measurements were repeated until 6 measurements were within the limits of the stability criterion (±0.1 mN/m) The individual results were averaged to give the final value

 σ= 52.7 mN/m (corrected according toZuidema and Waters¹). As the surface tension was lower than 60 mN/m, the test item had surface-active properties.

Description of key information

The surface tension was measured according to OECD 115, based on the measurement of the maximum vertical force, which is necessary to separate a ring being in contact with the liquid filled in a measuring cup from the surface of this liquid.

The surface tension of the aqueous solution of the substance (1000.0 mg/L) at 20 °C had a mean value of 52.7 mN/m. The test item had surface-active properties.

Key value for chemical safety assessment

Surface tension:

52.7

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

1 000