Preparation and characterization of microporous fibers for sample preparation and LC‐MS determination of drugs

Abstract

The aim of this study was the preparation of polypyrrole (PPy) fibers for solid phase microextraction (SPME). PPy coatings were obtained during the electrochemical polymerization process. The utility of various metal wires (Fe, Cu, Ag, Cu/Ag, kanthal and medical stainless steel) as a support for polymers was compared. Various experimental conditions of the synthesis process such as scan rate, voltage limits and number of scans and deposition time were applied. The average polymer thickness was in the range of 7-125 microm and its weight was in the scope of 0.65-5.6 mg. Different techniques, mainly elemental analysis, Fourier transform infrared spectroscopy, microscopy, and chromatography were performed for the characterization of obtained fibers with microporous structure. The extraction efficiency of cardiovascular drugs (metoprolol, propranolol, oxprenolol, propafenone and mexiletine) by means of fibers was tested. The concentration of mentioned compounds in standard solution was in the span of 10-150 ng/mL. LC-MS was employed for determination of drugs in desorption solution. LODs varied from 0.013 to 1.51 ng/mL for metoprolol and mexiletine respectively. The repeatability of extraction was obtained with the RSD values lower than 10%.

Polypyrrole solid phase microextraction: A new approach to rapid sample preparation for the monitoring of antibiotic drugs

“…The SEM analysis of the fibre morphology revealed the advantages of the modified preparation procedure in terms of an improved homogeneity and porosity of the resulting coating that allowed skipping the second polymerisation step under potentiostatic conditions applied earlier [17]. Furthermore, the thicknesses were found to be in a narrow range between 95 and 100 m. Fig.…”

“…The potentiostat/galvanostat instrument was connected to a three-electrode array consisting of an electrochemically roughened stainless steel (Ni-Cr) working electrode (∅ = 750 m, l = 10.0 cm), a platinum wire counter electrode, and an Ag/AgCl reference electrode. As distinct from [17], electrochemical polymerisation was carried out under potentiodynamic conditions known as cyclic voltammetry, applying −0.4 to +2.2 V and a scan rate 50 mV s −1 for seven cycles at a monomer concentration of 0.25 M. The fibres were characterised by scanning electron microscopy (SEM) using a LEO 1430VP instrument (Carl Zeiss SMT, Oberkochen, Germany). Fibre lengths were 1.3-1.5 cm.…”

“…Polypyrrole (PPy) fibres were manufactured electrochemically in modification of the procedure published previously [17] by now coupling the homemade electropolymerisation system to a new generation potentiostat/galvanostat PGSTAT128N series model from Autolab (Utrecht, The Netherlands). The potentiostat/galvanostat instrument was connected to a three-electrode array consisting of an electrochemically roughened stainless steel (Ni-Cr) working electrode (∅ = 750 m, l = 10.0 cm), a platinum wire counter electrode, and an Ag/AgCl reference electrode.…”

Application of 4-chloro-7-nitrobenzofurazan for the analysis of propafenone and diltiazem hydrochlorides using kinetic spectrophotometric and spectrofluorimetric methods

“…1/t) versus the initial concentration of the studied drugs (Table 10) was plotted (Figure 7 and 8). The following equations for calibration graphs were worked out by linear regression: 1/ t = 0.0003+ 15.759 C (r=0.9843) for propafenone HCl (9) 1/ t = 0.0003+ 6.5346 C (r=0.9847) for diltiazem HCl (10) The range of the concentration of the studied drugs giving the most acceptable calibration graph with the above equations was very limited, which could be disadvantage. …”

“…LC-flourescence detection [8] and LC-UV [9] detection were adopted for determination of propafenone. LC-MS [10], HPLC-MS [11], GC-MS [12], GCelectron-capture detection [13], TLC [14] and capillary electrophoresis [15] were also used for determination of the drug and its metabolites in pharmaceutical formulations and biological fluids. Propafenone was determined in blood serum using adsorptive-stripping voltammetry [16].…”