SPE
eluants were pH adjusted to 6.5 [+ or -] 0.5 before diluting to a final volume of 4.0 ml.
The plates were developed with acetone in hexane at different percentages as
eluants. The eluted plates were dried and first observed under 280 nm and 360 nm UV light after spraying with a 1% solution of [(N[H.sub.4]).sub.4]Ce-[(S[O.sub.4]).sub.4] x [H.sub.2]O in 2N [H.sub.2]S[O.sub.4] (J.
Chromatography was executed with silica gel (60-120 mesh) using mixtures of chloroform, methanol and hexane as
eluants. Visualization was obtained under UV light and spraying with 10% sulphuric acid in methanol.
Pb isotopic analyses was separated using microexchange columns of anion resin of Dowex-I (200-400 mesh) and HBr and HCl as
eluants [11].
The column elution experiments indicated that the concentration of the
eluants depends on the rate of elution.
The lyophilized ethanolic extract was redissolved at 20mg/mL in absolute alcohol and subjected to RP-HPLC by employing C18 column (shim-pack column 250 x 4.6 mm and particle size 5 [micro]m) with 1 mL/min flow rate, and the
eluants were monitored at 280 nm.
Fractions containing antifungal activity were pooled, centrifuged at 11,000 G for 5 minutes, and further purified by reverse-phase HPLC on a [C.sub.8] column (Varian) using buffer A (0.1% TFA) and buffer B (0.1% TFA plus 90% acetronitrile) as
eluants. The flow rate was 0.7 mL.[min.sup.-1] and the absorbances of the fractions were measured at 214 nm.
The nature of fatty acids in the lipid extract of our study was determined by gas liquid chromatography (GLC) by comparing the relative retention time of the
eluants from 'eengol" food products, with the retention time of similar fatty acids in the standard mixture of known fatty acids.
Wade's color reagent (Wade and Morgan, 1955), consisting of 0.015% (w/v) Fe[Cl.sub.3] and 0.15% (w/v) 5-sulfosalicylic acid (also at flow rate of 1 mL [min.sup.-1]) and PA eluted from the column, were mixed in a mixing tee with inline check valves for both
eluants installed before the mixing tee to prevent backflow.
The concentrated
eluants were then fractionated by liquid chromatography using a semi-preparative aminopropyl-silane column with hexane as the mobile phase.