TY - JOUR

T1 - Performance and Stability of the Organosilicone Surfactant L-77

T2 - Effect of pH, Concentration, and Temperature

AU - Knoche, Moritz

AU - Tamura, Hiroto

AU - Bukovac, Martin J.

PY - 1991/1/1

Y1 - 1991/1/1

N2 - Studies on the effect of the organosilicone surfactant Silwet L-77 (0.1% w/v) on uptake of [14C]GA3 (0.5 mM GA3, pH 3.0) by sour cherry leaves (Prunus cerasus L. Montmorency) showed a significant decline in GA3 absorption when the treatment solution was prepared 12 h prior to application compared to a freshly prepared solution. Surface tension of a freshly prepared solution (22.4 mN m−1) increased rapidly after a 76-min lag period. Gas chromatographic analysis revealed that Silwet L-77 degraded at pH 3.0 with a half-life of 43 min. Degradation velocity was dependent on pH. Slopes of the surfactant (0.1%) degradation curves at pH 3, 4, 5, 9, and 10 were 361.9, 69.2, 12.3, 6.2, and 14.8 mN m−1 day−1, respectively. Duration of the lag phase was linearly related with concentration between 0.025 and 0.4 %. No lag phase was apparent below the critical micelle concentration (cmc = 0.008%). Degradation increased significantly with an increase in temperature from 15 to 35 °C. A related surfactant, Silwet L-7607, and two experimental organosilicone surfactants (0.1% and pH 3) also degraded significantly within 3 h. The significance of this degradation is discussed in relation to spray application.

AB - Studies on the effect of the organosilicone surfactant Silwet L-77 (0.1% w/v) on uptake of [14C]GA3 (0.5 mM GA3, pH 3.0) by sour cherry leaves (Prunus cerasus L. Montmorency) showed a significant decline in GA3 absorption when the treatment solution was prepared 12 h prior to application compared to a freshly prepared solution. Surface tension of a freshly prepared solution (22.4 mN m−1) increased rapidly after a 76-min lag period. Gas chromatographic analysis revealed that Silwet L-77 degraded at pH 3.0 with a half-life of 43 min. Degradation velocity was dependent on pH. Slopes of the surfactant (0.1%) degradation curves at pH 3, 4, 5, 9, and 10 were 361.9, 69.2, 12.3, 6.2, and 14.8 mN m−1 day−1, respectively. Duration of the lag phase was linearly related with concentration between 0.025 and 0.4 %. No lag phase was apparent below the critical micelle concentration (cmc = 0.008%). Degradation increased significantly with an increase in temperature from 15 to 35 °C. A related surfactant, Silwet L-7607, and two experimental organosilicone surfactants (0.1% and pH 3) also degraded significantly within 3 h. The significance of this degradation is discussed in relation to spray application.

UR - http://www.scopus.com/inward/record.url?scp=33751499588&partnerID=8YFLogxK

U2 - 10.1021/jf00001a041

DO - 10.1021/jf00001a041

M3 - Article

AN - SCOPUS:33751499588

VL - 39

SP - 202

EP - 206

JO - Journal of Agricultural and Food Chemistry

JF - Journal of Agricultural and Food Chemistry

SN - 0021-8561

IS - 1

ER -