Quantitative analysis of strain-producer of industrial culture fluids antibiotic fosfomycin methods of planar chromatography and capillary electrophoresis

Abstract

Quantitative TLC analysis procedure of determination of the antibiotic fosfomycin in the culture liquid
(QL) of Streptomyces wedmorensis strain was developed. Chromatography was performed on silica
plates Sorbfil PTLC-AF-V-UV by upstream method with camera saturation with the mobile phase for 1 hour.
Mixture of propanol-2 – ethanol - 25% aqueous ammonia - water (7.0:7.0:4.0:2.0 volume ratio) was used as
the mobile phase. Visualization of the spots of fosfomycin was carried out by immersion of the TLC plate
into a solution of mixture of ammonium rodanide (0,9 wt.%) and manganese rodanide (0.1 wt.%) in acetone
for 3 seconds, air-dried for 20 min and immersed into a solution of iron chloride hexahydrate (0.075 wt.% )
in acetone. It was found, that the coloring of the chromatographic areas (brown spots on a yellow background)
were stable for 2 hours at 20oC. Quantitative determination of fosfomycin was performed on the densitometers at a wavelength 470 nm. The limit of detection of the fosfomycin was 0.15 μg / spot. Capillary
electrophoresis (CE) was used as a reference method, the quantification limit was 25 mg/L. To reduce the
time of QL sample preparation for electrophoresis unit equipped with a regenerated cellulose ultrafiltration
membrane with a nominal cutoff of 30 kDa was used; the filtration time was 10 min. Current study demonstrates,
that data on determination of fosfomycin in the samples of QL, performed by quantitative High Performance
TLC and capillary electrophoresis are in the good agreement, r=0.9931