The mobile phase was MeOH-H2O, 80 20 (v/ v) at the beginning of a chromatographic run and increased within 2 min to 100% MeOH to achieve rapid elution of the oxidation products.
For methamphetamine and amphetamine a mobile phase of MeOH-cc.
The first fractionation was performed using a reversed-phase (RP) HPLC system at 22 °C, with a C18 semi-preparative column (Vydac 201TP510, 5 μm, 10.0 × 250 mm; mobile phase initially 50% MeOH and 50% H2O (4.7 ml/min), changing linearly to 100% MeOH in 50 min and kept at 100% MeOH during 40 min) [ 17].
The reaction monitoring was carried out by Thin Layer Chromatography (TLC) using as mobile phase DCM: methanol (MeOH) = 9.5: 0.5 (v/v) and the spot visualization was done under UV light at 254 nm.
Samples, dissolved in methanol, were analysed using a C18 column (RP C18, Xterra, 5 μm, 4.6 × 150 mm) and a mobile phase consisting of MeOH and phosphate buffer (0.1 M, pH 7.5) compounds were estimated by a comparison of its retention time to that of standards of known log P values.
Use of two organic components in mobile phase (ACN and MeOH) resulted in better separation of analytes in comparison to the separation achieved with only one organic component.
As mobile phase two solvents, MeOH and ultra-purified water were used, both buffered at pH4 with ammonium formate (10 mM).
The mobile phase was 39 % MeOH in 0.1 M NH4HCO2 buffer at a flow rate of 5 mL/min.
Following termination of fermentation and extract preparation using above mentioned protocol, TLC profiles of the both the extracts were compared in mobile phase containing 5% MeOH in DCM.
TLC profile of the extract from the valproic acid treated culture showed the presence of a UV visible spot at Rf value of 0.70 in mobile phase containing 5% MeOH in DCM which was not visible in the extract of the culture grown without valproic acid.
The mobile phase was 50% MeOH, 49.5% Milli-Q water, 0.1 m m EDTA, and 0.5% phosphoric acid (pH 2.5).
