128 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS ducible, simple, and quick method to measure cationic polymer substantivity on hair. For this purpose, gel permeation chromatography (GPC) has been validated as a method to measure the adsorption of cationic polymers on hair. The uptake of nine cationic conditioning polymers on bleached hair was measured indirectly by determining the difference in polymer concentration in solutions before and after the treatment of the hair. This paper describes, in detail, the GPC procedure needed for the determination of cationic polymer uptake by hair. The effects of polymer molecular weight and mole percent of cationic net charge on the substantivity of the polymers are also reported. EXPERIMENTAL CONDITIONS Bleached blond hair 8 inches long from De Meo Brothers, New York, was used in this investigation. The cationic polymers used are listed in Table I, and the treatment solutions were 0.10% aqueous polymer solutions, pH 6.0 + 0.1. The study was con- ducted at 22øC. PREPARATION OF HAIR SAMPLES Bleached blond hair tresses were thoroughly washed by alternately immersing them in 15% active Triton X-100 solution and rinsing them with deionized water. After this treatment, the hair tresses were immersed for 1 hour in a 60% acetone/1% NaC1 aqueous solution and then rinsed thoroughly. SUBSTANTIVITY STUDY SAMPLE PREPARATION Washed hair (2.30 g) was allowed to soak in 150 ml of treatment solution for 30 minutes. A reciprocating mixer with a speed of 420 min -1 was used to agitate the Table I Cationic Polymers Used in the Investigation Trade name INCI name Merquat 5501 Merquat 280 • Merquat 20001 Merquat Plus 33301 Merquat 1001 Gafquat 755N 2 Gafquat HS 1002 Polymer JR 4003 Celquat L-2004 Polyquaternium 7 Polyquatermum 22 Polyquaternmm 47 Polyquatermum 39 Polyquatermum 6 Polyquatermum 11 Polyquatermum 28 Polyquatermum 10 Polyquatermum 4 1 Calgon Corporation, Pittsburgh PA 15230. 2 International Specialty Products, Wayne, NJ 07470. 3 Amerchol Corporation, Edison, NJ 08818. 4 National Starch and Chemical Company, Bridgewater, NJ 08807.

GEL PERMEATION CHROMATOGRAPHY 129 samples. At the end of the treatment time, the hair was squeezed using a pair of tweezers and removed from the treatment solution. The remaining solutions were called post- treatment solutions. The hair was then rinsed three times with 50 ml of deionized water each time, and all of the rinses were collected for analysis. Untreated treatment solutions (without hair) were subjected to the same conditions. All experiments were performed in triplicate. SAMPLE ANALYSIS The treatment solutions, the post-treatment solutions, and the rinses were analyzed using the following equipment: Intrument: Water's GPC Detectors: Water's 410 RI, Wyatt MALLS Column: TSK PW3000 Eluent: 0.15 M Na2SO 4 + 1% Acetic acid, pH 3.3 Flow: 1.0 ml/min Temp: 25øC Vol: 200 pL Two injections of each treatment solution were made. Based on the polymer mass injected and the refractive index polymer peak area, the specific refractive index incre- ment (dn/dc) of each sample was computed. The two dn/dc values were averaged. Two injections of each post-treatment solution were made. The mass of the polymer injected was then determined based upon the refractive index polymer peak area and the dn/dc measured from the treatment solution. The same procedure was used to compute the mass of polymer in each rinse. The amount of polymer found in the rinses was negligible. The average of the three polymer determinations for each experiment was obtained. The calculated difference in the amount of cationic conditioning polymer present in the treatment and post-treatment solutions represents the cationic polymer uptake by the hair sample. The analysis of the untreated solutions (without hair) showed no degrada- tion of polymer due to handling for any of the polymers. The data obtained were statistically analyzed using a t-test (1) to determine whether the measured polymer mass in the treatment and post-treatment solutions were statistically different. RESULTS AND DISCUSSION Figure 1 depicts the substantivity values obtained for different polymers. We wanted to determine the effect of polymer molecular weight and mole percent of cationic net charge on the substantivity of the polymers. The molecular weight of the polymers and the mole percent of cationic net charge values provided by the respective suppliers were used for this determination. See Figures 2 and 3. There appears to be no direct correlation between the substantivity of the polymers under the tested conditions and their molecular weight or mole percent cationic net charge. The latter two factors, plus the ability of the polymer to form hydrogen bonding