On-line solid-phase enrichment coupled to packed reactor flow injection analysis in a green analytical procedure to determine low levels of folic acid using fluorescence detection

Abstract

BackgroundAnalysis of folic acid (FA) is not an easy task because of its presence in lower concentrations, its lower stability under acidic conditions, and its sensitiveness against light and high temperature. The present study is concerned with the development and validation of an automated environmentally friendly pre-column derivatization combined by solid-phase enrichment (SPEn) to determine low levels of FA.ResultsCerium (IV) trihydroxyhydroperoxide (CTH) as a packed oxidant reactor has been used for oxidative cleavage of FA into highly fluorescent product, 2-amino-4-hydroxypteridine-6-carboxylic acid. FA was injected into a carrier stream of 0.04 M phosphate buffer, pH 3.4 at a flow-rate of 0.25 mL/min. The sample zone containing the analyte was passed through the CTH reactor thermostated at 40°C, and the fluorescent product was trapped and enriched on a head of small ODS column (10 mm x 4.6 mm i.d., 5 μm particle size). The enriched product was then back-flush eluted by column-switching from the small ODS column to the detector with a greener mobile phase consisting of ethanol and phosphate buffer (0.04M, pH 3.4) in the ratio of 5:95 (v/v). The eluent was monitored fluorimetrically at emission and excitation wavelengths of 463 and 367 nm, respectively. The calibration graph was linear over concentrations of FA in the range of 1.25-50 ng/mL, with a detection limit of 0.49 ng/mL.ConclusionA new simple and sensitive green analytical procedure including on-line pre-column derivatization combined by SPEn has been developed for the routine quality control and dosage form assay of FA at very low concentration level. The method was a powerful analytical technique that had excellent sensitivity, sufficient accuracy and required relatively simple and inexpensive instrumentation.

Sensitivity Enhancement for Separation-Based Analytical Techniques Utilizing Solid-Phase Enrichment Approaches and Analyte Derivatization for Trace Analysis in Various Matrices

“…At 530 nm wavelength, measurement was conducted for the resulting pink product. Green analytical techniques for measuring folic acid (FA) and MTX have been developed and validated using online derivatization in conjunction with column switching and an RP-C18 short column for SPEn [191,192]. The procedures employed a packed reactor containing cerium (IV) trihydroxyhydroperoxide (CTH) to oxidatively break down FA and MTX into highly fluorescent 2-amino-4-hydroxypteridine-6-carboxylic acid and 2,4-diaminopterdine-6-carboxylic acid, respectively (Schemes 1 and 2), and then enriching the reaction products on short RP-C18 columns.…”

Sustainable and Eco-Friendly Alternatives for Liquid Chromatographic Analysis

“…A good compromise between analytical features and sustainability was reached in the determination of prednisolone in tablets by using an ethanol:water, 30:70, v:v mobile phase on C-18 columns at 50 °C, obtaining an analysis time of 12 min per sample . Ethanol:phosphate buffer mobile phases 5:95, v:v are capable to separate with efficiency, precision, and accuracy folic acid in tablets in the 1.25–50 ng/mL range of concentrations . Coenzyme Q10 has been determined in bee pollen samples with a C-18 stationary phase and pure ethanol as mobile phase.…”

“…74 Ethanol:phosphate buffer mobile phases 5:95, v:v are capable to separate with efficiency, precision, and accuracy folic acid in tablets in the 1.25−50 ng/mL range of concentrations. 75 Coenzyme Q10 has been determined in bee pollen samples with a C-18 stationary phase and pure ethanol as mobile phase. This procedure combines green analytical pretreatment and HPLC separation.…”

Determination of Aniline Blue dye by Flow Injection Analysis With Home Made Valve

“…The result signal recorded as single peak which has height , area , time of sample analyzing appearance and the width of peak 7 . FIA can be modified by many ways: revers FIA 9 , merging zone 10 and stop flow 11 and can be connected with chemluminescence 12 ,fluorescence 13 and luminescence 14 .…”