Pirimiphos-methyl

Surface tension

Link to relevant study record(s)

Reference

Endpoint:

surface tension

Type of information:

experimental study

Adequacy of study:

key study

Study period:

10 Oct 2014 to 19 Oct 2014

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)

Version / remarks:

27 Jul 1995

Qualifier:

according to guideline

Guideline:

EU Method A.5 (Surface Tension)

Version / remarks:

30 May 2008

GLP compliance:

yes (incl. QA statement)

Type of method:

ring method

Key result

Surface tension:

58.5 mN/m

Temp.:

21 °C

Conc.:

90 vol%

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 in 'Any other information on results incl. tables', 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 in 'Any other information on results incl. tables', respectively.

- Surface tension= reading x calibration factor

- Sample Solution A  = 58.3 x 1.003

- Sample Solution A = 58.5 mN/m

- Sample Solution B = 58.3 x 1.003

- Sample Solution B = 58.5 mN/m

- Overall mean = 58.5 mN/m

- Temperature = 21.0 ± 0.5 ºC

-  pH of sample solution = Sample Solution A = 5.8; Sample Solution B = 5.8

 

On completion of the static equilibration period at 20 °C, both aqueous samples contained undissolved, excess test item at the base of the flask; indicating that saturation had been achieved. Following centrifugation, the isolated supernatants were clear, colourless solutions and visually confirmed to be free from any excess, undissolved test item prior to diluting to 90 % saturation.

Table 3 Water Calibration Data Relevant To Sample Solution A

Reading (mN/m)	Temperature (ºC)	Literature Value (mN/m)	Calibration Factor
72.5	21.2	72.53	1.000
72.0	21.2	72.53	1.007
72.0	21.2	72.53	1.007
72.5	21.2	72.53	1.000
72.5	21.2	72.53	1.000
72.0	21.2	72.53	1.007
72.5	21.2	72.53	1.000
72.5	21.2	72.53	1.000
Mean Calibration Factor = 1.003

Table 4  Water Calibration Data Relevant To Sample Solution B

Reading (mN/m)	Temperature (ºC)	Literature Value (mN/m)	Calibration Factor
72.5	21.2	72.53	1.000
72.0	21.2	72.53	1.007
72.5	21.2	72.53	1.000
72.0	21.2	72.53	1.007
72.5	21.2	72.53	1.000
72.5	21.2	72.53	1.000
72.0	21.2	72.53	1.007
Mean Calibration Factor = 1.003

Table 5 Sample Solution A Surface Tension Measurements

Time (mins)	Temperature (ºC)	Reading (mN/m)
85	21.2	59.5
94	21.2	58.0
106	21.2	58.5
116	21.2	58.5
126	21.2	58.0
138	21.2	58.5
149	21.2	58.5
Mean sample reading = 58.3^*

*Last six values considered to be a stable plateau of surface tension readings and therefore used in the calculation of the mean.

Table 6 Sample Solution B Surface Tension Measurements

Time (mins)	Temperature (ºC)	Reading (mN/m)
166	21.2	58.5
176	21.2	58.5
186	21.2	58.5
197	21.2	58.0
208	21.2	58.0
220	21.2	58.0
Mean sample reading = 58.3^†

† All values considered to be a stable plateau of surface tension readings and therefore used in the calculation of the mean.

Conclusions:

The average surface tension of duplicate 90% saturated solution of test substance in water has been determined to be 58.5 mN/m at 21.0 ± 0.5 °C.

Executive summary:

The study was performed to determine the surface tension of the test substance in accordance with OECD TG 115 and EU Method A5 in compliance with GLP. The average surface tension of duplicate 90% saturated solution of test substance in water has been determined to be 58.5 mN/m at 21.0 ± 0.5 °C.

Description of key information

58.5 mN/m in a 90% saturated solution at 21.0 ± 0.5 °C, ring method, OECD TG 115, O'Connor 2014.

Key value for chemical safety assessment

Surface tension:

58.5

Additional information

Another study was performed to determine the surface tension of the test substance in technical material in accordance OECD TG 115 and in compliance with GLP. In this study, the surface tension was determined to be 62.9 mN/m