Turbulent flow chromatography, TFC

Direct injection of pretreated biological samples (also called online sample cleanup) greatly simplified sample preparation for LC/MS/MS analysis. The normal process involves sample aliquot steps, internal standard addition, and centrifugation. Compared to traditional off-line LLE and SPE sample preparation procedures, online methods are easier and faster. Two types of online SPE columns are commercially available. One is the restricted access media (RAM) column. The other is the turbulent flow chromatography (TFC) column. 

Ceglarek et al.45 reported the rapid simultaneous quantification of immmunosuppressants (cyclosporine A, tacrolimus, and sirolimus) in transplant patients by turbulent flow chromatography (TFC) coupled with HPLC-MS/MS. TFC is an online extraction technique involving the direct application of human plasma onto a turbulent flow column where protein is washed from the samples before the retained drug is backflushed onto an analytical column. 

High flow rate is generally the basis for the high-throughput efficiency of several Turbulent Flow Chromatography (TFC), Restricted Access Material (RAM), and monolithic columns methodologies. 

Recently, turbulent flow chromatography (TFC) has shown a great potential for online sample pre-treatment in the analysis of PFCs. Up to now, the use of this technique in food and environmental analysis is scarce, but some successful applications have been developed. Among them, the analysis of PFCs has been carried out in cord blood and also in less invasive human samples, hair and urine. In these works, the main advantages presented were the simplified sample preparation, robustness and sensitivity. In addition in the case of cord blood, a low volume of sample was required. 

Turbulent-flow chromatography (TFC) was first described in the 1960s. Sternberg and Poulson (1964) showed how turbulent-flow increases the effective diffusivity of... 

Solid-phase extraction (SPE), which can be done off-hne or on-line by means of cartridges, cartridge columns, or extraction disks (Ch. 11.6.4), and eventually by using special packing materials, such as restricted access materials (RAM) or turbulent-flow chromatography (TFC) (Ch. 11.6.5). 

Many different sample preparation techniques are available to the drug discovery scientist. Off-line sample preparation procedures include protein precipitation, filtration, dilution followed by injection, liquid-liquid extraction (LLE), and solid-phase extraction (SPE). Typically, these procedures are performed in an automated, high-throughput mode that features a 96-well plate format. Online sample preparation procedures include SPE and turbulent flow chromatography (TFC) with conventional chromatographic media or restricted access media (RAM). These online approaches are often simple and easy to automate. 

Aguilera-Luiz, M. M., Romero-Gonzalez, R., Plaza-Bolanos, P, Vidal, J. L. M., and Frenich, A. G. 2013. Rapid and semiautomated method for the analysis of veterinary drug residues in honey based on turbulent-flow hquid chromatography coupled to ultra high-performance hquid chromatography-orbitrap mass spectrometry (TFC-UHPLC-Orbitrap-MS). J. Agr. Food Chem. 61 829—839. 

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