Contribution of multi-commuted flow analysis combined with monolithic columns to low-pressure, high-performance chromatography

The advent of monolithic columns has facilitated the combination of chromatographic techniques with non-separation flow techniques [particularly sequential injection analysis (SIA) and multi-syringe flow-injection analysis (MSFIA)] by virtue of the low overpressure introduced by monolithic columns. So far, these combinations have provided excellent results derived from the high selectivity of liquid chromatography and ease of sample handling in non-separation flow techniques.The joint use of SIA and monolithic columns has provided SI chromatography (SIC), which could enormously facilitate sample treatments (e.g., derivatization, photooxidation or preconcentration). However, the combination of MSFIA and monolithic columns has led to multi-syringe chromatography (MSC), which extends the advantages of SIC (e.g., by implementing post-column reactions in order to derivatize eluates).We discuss the advantages and the disadvantages of SIC and MSC, and the problems to be solved in order to optimize their performances.