The Study of a Simple Pine-Oil Based Laboratory Prepared and Commercial Detergents Using Conductivity Measurements

Abstract

Detergents are very important substances in everyday life as they are used in laundry services. This manuscript reports the study of the commercial and laboratory prepared pine oil-based detergents employing the critical micelle concentration (CMC) phenomenon using conductivity measurements. The two samples showed the CMC values of 0.0725 g/cm 3 and 0.0920 g/cm 3 for laboratory and commercial samples respectively. The effect of ionic strength was investigated using NaCl and it demonstrated a drop of CMC value of about CMC by 40% (laboratory sample) and 70% (commercial sample) while the equi-molar naphthalene increased the CMC values by about 50% (laboratory sample) and 12% (commercial sample) relative to their corresponding values under distilled water. The combined effect of equi-molar NaCl and naphthalene lowered the CMC by 5% (laboratory sample) and 30% (commercial sample). These differences could signify the superiority of the laboratory sample in that it is somehow buffered against drastic changes in the CMC under different conditions. The relationship between conductivity and the CMC values does not show sufficient linearity (R 2 < 0.8403) suggesting different mechanisms of interactions between NaCl and naphthalene. Overall, the results are gratifying to the small-scale manufacturer who supplied the preparation protocol for laboratory sample preparation, in two respects: they inspire some degree of confidence in his product as well as enabling the manufacturer to employ the same protocol for his quality control practices as such improve product consistency and hence profitability.