Lipoic Acid Lab Report

Materials
Alpha Lipoic acid (purity > 99.90%) was obtained from EVA PHARMA for Pharmaceuticals & Medical Appliances, Cairo, Egypt. Merbromin reagent was purchased from El-Nasr Chemical Ind. Co., Egypt. Reagents for preparing McIlvaine’s Buffer (Citric acid monohydrate and disodium monohydrogen phosphate) were purchased from El-Nasr Chemical Ind. Co., Egypt. Lipoic acid capsules (Batch No. A40158) labeled to contain 100 mg Lipoic acid per capsule were purchased from the Canadian market (WN Pharmaceuticals®.Ltd, B.C., Canada V3k 7B5.)

Instrument
Fluorescence spectra and measurements were carried out on a Perkin-Elmer LS 45 luminescence spectrometer, equipped with a 1-cm quartz cell. The instrument is interfaced to a computer loaded with FL

To each flask, a volume of 2 mL MER solution, followed by 4 mL of buffer solution (pH 6) were added, mixed well and made up to volume with distilled water. They were allowed to stand for 45 min. A reagent blank was prepared in the same manner. The fluorescence intensities of the blank (Fo) and of each solution (F) were measured (λex = 295 nm and λem = 516 nm). The two calibration curves; ∆F (Fo-F) vs LA conc., and F-ratio (Fo/F) vs LA conc. were constructed.

2.2.1. Data Sets:

Robust regression calculations; LMS and IRLS, have been applied to the calibration data of the fluorescence quenching reaction results (both ∆F and F-ratio methods); Stern-Volmer equation. Two real data sets are included; named the ideal case and the non-ideal case. These data sets are two different raw data sets obtained from the fluorimetric reaction mentioned under Construction of calibration curve, on two different days. Each data set includes results of both methods (∆F and F-ratio).
● The ideal case;
-Set of 7 pairs of data obtained from ∆F method;
{(2.5, 13), (5, 14.5), (7.5, 15), (10, 16.11), (50, 22.25), (60, 24), (70,