2.5. Analytical quality control
In the HPLC separation of unsaponifiables, linear calibration
curves were obtained for a-tocopherol (27–
140 lg/ml, r2 = 0.9999), cholesterol (800–4800 lg/ml,
r2 = 0.9999) and squalene (30–80 mg/ml, r2 = 0.9999). To
compensate for any day-to-day variations, each day of
analysis a set of standards was routinely saponified and
run under the same conditions as the samples