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Physical & Chemical properties

Surface tension

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Administrative data

surface tension
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2012-10-08 to 2013-01-09
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference Type:
study report
Report date:

Materials and methods

Test guidelineopen allclose all
according to guideline
OECD Guideline 115 (Surface Tension of Aqueous Solutions)
according to guideline
EU Method A.5 (Surface Tension)
GLP compliance:
Type of method:
OECD harmonised ring method

Test material

Constituent 1
Chemical structure
Reference substance name:
2-[[(4-methoxyphenyl)methylhydrazono]methyl]-1,3,3-trimethyl-3H-indolium methyl sulphate
EC Number:
EC Name:
2-[[(4-methoxyphenyl)methylhydrazono]methyl]-1,3,3-trimethyl-3H-indolium methyl sulphate
Cas Number:
Molecular formula:
C20H24N3O.CH3O4S C21H27N3O5S
2-{[2-(4-methoxyphenyl)-2-methylhydrazin-1-ylidene]methyl}-1,3,3-trimethyl-3H-indol-1-ium methyl sulfate
Test material form:

Results and discussion

Surface tension
Surface tension:
48.62 mN/m
20 °C
1 g/L
Remarks on result:
other: Mean value corrected by Zuidema and Waters (Ind. Eng. Chem. Analyt. 13 (1941), S.312)

Any other information on results incl. tables

Individual Results:

An aqueous solution of the test item in de-ionized water with a concentration of 1 g/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 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 table 1). 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 a constant surface tension value in 6 measurements is reached.

Table 1: Measurement of the surface tension
Measurement  1 2 3 4 5 6
Time (s) 1191 1251 1313 1375 1437 1499
σ (mN/m) 48.7 48.66 48.63 48.61 48.57 48.58

Mean value:   s = 48.62 mN/m (corrected by Zuidema and Waters)

Due to the fact that the surface tension is lower than 60 mN/m, the test item has surface-active properties.

Applicant's summary and conclusion

In conclusion, the surface tension of the aqueous solution at 20 °C is 48.62 mN/m. The test item has surface active properties.
Executive summary:

The surface tension of the test item was measured with the OECD ring method according to EU method A.5 (OECD guideline 115). The mean surface tension of six measurements at 20 °C is 48.62 mN/m.

Due to the fact that the surface tension is lower than 60 mN/m, the test item has surface-active properties.