Modulation of mobile phase composition in flow-injection/sequential-injection chromatography exploiting multisyringe flow analysis

Abstract

In this paper, a time-based multicommutated flow system is proposed for appropriate selection and modulation of mobile phase composition in flow-injection (FI)/sequential-injection (SI) chromatography. The novel flow assembly involves the on-line coupling of a short monolithic reversed-phase chromatographic column with a multisyringe flow injection set-up furnished with a set of solenoid valves. The proposed hyphenated technique was applied to the simultaneous spectrophotometric determination of thiamine (B(1)), pyridoxine (B(6)) and cyanocobalamin (B(12)) which were taken as model analytes. The separation method capitalizes on a dual isocratic elution protocol involving the use of a single forward stroke of the multisyringe pump for initial delivery of 50 mmol L(-1) ammonium acetate (pH 7.0) for 2.4 min followed by 50 mmol L(-1) ammonium acetate-methanol (80:20, v/v) for 6.4 min at 0.5 mL min(-1) and room temperature. Detection was performed at the maximum wavelength for each target vitamin-280 nm for B(1), 325 nm for B(6), and 360 nm for B(12). A first-order, two-level full-factorial design was utilized to ascertain the significant variables influencing the chromatographic separation and the magnitude of the interaction effects. The experimental design method revealed that resolution of the target vitamins is highly dependent on the pH, percentage of organic modifier, and their second-order interaction. The multisyringe flow-injection-based monolithic column separation method, which should be viewed as an expeditious and cost-effective alternative to the high-performance liquid chromatography counterpart, was applied to the separation and determination of B(1), B(6), and B(12) in different pharmaceutical dosage forms in less than 9 min. Statistical comparison of the results from the proposed procedure with those from the HPLC method endorsed by the US Pharmacopeia revealed there were no significant differences at the 95% confidence level.

The Second Five Years of Sequential Injection Chromatography: Significant Developments in the Technology and Methodologies

“…The efficiency of separation in SIC was also improved using a new approach of isocratic mode. Fernández et al (2008) demonstrated the hyphenation of MSFIA with SIC. An MSFIA setup was furnished with two solenoid valves to manipulate two mobile phases.…”

“…The gradient elution was achieved by automated reproducible mixing of acetonitrile and aqueous 0.2% phosphoric acid in the HC installed in an SIC system. A dual isocratic elution protocol involving a multi-syringe pump for delivery of two mobile phases was also proposed (Fernández et al, 2008).…”

Monosegmented Flow Analysis Exploiting Aqueous Two-phase Systems for the Determination of Cobalt

“…ANOVA is a useful method for evaluating a two-level factorial design. 31 The results obtained from ANOVA shown that KSCN concentration (denoted as [KSCN]), the pH, the volume of the L1 coil and the interactions [KSCN]/pH and [KSCN]/L1 are significant factors affecting the response. The concentration of KSCN is the most pronounced effect, as shown by runs 2, 4, 6 and 8 (Table 2), which correspond to the highest level of this variable.…”

Two-column Sequential Injection Chromatography—New approach for fast and effective analysis and its comparison with gradient elution chromatography

“…González-San Miguel et al used MSC with three solenoid valves coupled with Chromolith ® monolithic column for determination of ␤-lactam antibiotics and discuss comparison of SIC and MSC [9][10][11]. Fernández et al set-up MSC for appropriate selection and modulation of mobile phase composition and applied it to the simultaneous spectrophotometric determination of thiamine, pyridoxine and cyanocobalamin in pharmaceuticals [12]. Obando et al proposed use of a separation method based on on-line coupling of a multi-syringe flow system with a chromatographic monolithic column for simultaneous determination of hydrochlorothiazide and losartan potassium in tablets [13] and in superficial water, groundwater and waste water outlet samples [14].…”