NITROSAMINE ANALYSIS 239 substituted for the standard stainless steel HPLC columns. Confirmation of structure by Mass Spectroscopy was performed on a Finnigan 4000 GC-MS data system. Standard NDE1A was obtained from Columbia Organic Chemical Company (Colum- bia, SC). Methanol used for analysis was HPLC-grade and the chloroform used was J. T. Baker's Photrex reagent-grade solvent. Distilled water was purchased from the Electrified Water Company or prepared from a Milli-Q system. The HPLC column used for the reverse phase separations was/.tBondapak C•8, while the normal phase separations were on a /.tPorasil column. Both columns were manufactured by Waters Associates. For some of the analysis, a Whatman Partisil PXS 10/25 ODS was also acceptable. B. METHOD OF ANALYSIS FOR ETHANOLAMINES HPLC parameters.' Column/.tBondapak C•8 (octadecylsilane), Waters Associates, 3.9 mm I.D. x 30.0 cm, stainless steel or Whatman Partisil PXS 10/25 ODS. Solvent A--distilled H20. Solvent B--methanol. Flow rate--l.O ml/min. Pressure (-6perating range)--O-6000 psi. Detector sensitivity--O-O.005 aufs. Recorder a) Range--10 my. b) Chart speed--10 ram/min. Pre column--Waters Associates, 3.9 mm I.D. x 3.0 cm, C•8 porasil stainless steel (optional). Solve n t progra m: a) Initial conditions--Solvent A (100%). b) Hold time--7 min. c) Run time (Solvent A to Solvent B)--3 min. d) Final Conditions--Solvent B (80%). e) Hold for 20-25 min. f) Reverse time (Solvent B to Solvent A)--10 min. g) Final conditions--Solvent A (100%) (allow 30 min. to equilibrate between runs). h) Programming is not needed for NDEIA standard runs, use only Solvent A. Procedure Preparation of N- nitrosodiethanolamine (NDElA ) standards: 1. Weigh 0.1000 g (0.08-0.12 g) of NDE1A into 100-ml volumetric flask. 2. Add 20 ml of Solvent A, swirl until NDE1A is dissolved, then dilute to volume with Solvent A. This gives a stock solution of (800-1200 ppm) NDE1A. 3. Pipet 1 ml of stock solution into 100-ml volumetric flask. Dilute to volume with Solvent A. This gives a working stock solution of 10 ppm (8-12 ppm) NDE1A.

240 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS 4. Prepare the following standards: 1.2, 1.0, 0.8 ppm by pipeting appropriate mls of working stock solution into volumetric flasks, and diluting to volume with Solvent A. Preparation of standard linearity curve for NDEIA.' 1. Start instrument and allow 15 min. to equilibrate using Solvent A. 2. Inject 25 3tl of Solvent A to check for any interference. 3. Inject (in triplicate) 25 3tl of the following standards: 1.2, 1.0, 0.8 ppm. 4. Record the peak height (cm) of each standard. 5. Take the average peak height of the standards and plot the peak height (cm) versus the concentration (ppm). A linear curve should be obtained. 6. Calculate slope and y-intercept of the linearity curve by a regression line analysis of the total standard data points. Sample preparation.' 1. Weigh 2.5--3.0 grams of sample into 10-ml volumetric flask. 2. Add 3 ml of Solvent A and swirl until sample dissolves, then dilute to volume with Solvent A. Determination of NDEIA in di- and triethanolamine: 1. Inject 25 3tl of Solvent A to check for any interference. 2. Inject 25 3tl of sample solution. Program the instrument after NDEIA peak is eluted (Refer to solvent program). 3. Record peak height (cm) of NDEIA in sample. 4. To determine the concentration (ppm) of NDE1A present in the sample solution, use the following equation: y=ax+b y = concentration of NDE1A (ppm) found in sample solution a = slope x = peak height (cm) b = y-intercept (a and b were calculated from standard NDEIA data points). 5. To determine total amount of NDE1A present in the original triethanolamine sample, use the following equation: Sample vol. ppm (original sample)= ppm (found) x Sample wt. C. METHOD OF ANALYSIS FOR LAURAMIDE DEA A Whatman (Partisil PXS 10/25 ODS) was used for the analysis, the remaining HPLC parameters used were the same as those for the analysis of the ethanolamines. Solvent Program.' a) Initial conditions--60% Solvent A/40% Solvent B (V/V). b) Hold time--5 min. c) Run time (initial condition to final condition)--3 min. d) Final condition--20% Solvent A/80% Solvent B (V/V).