Separation Technologies in Clinical Liquid Chromatography

PREANALYTICAL SPECIMEN HANDLING IN CLINICAL LIQUID CHROMATOGRAPHY 

None or minimal direct injection Ease, speed, cost, potential for automation Rarely feasible, requires relatively clean matrix (i.e., urine) and analyte that requires no preconcentration, may still require filtration or centrifugation to clarify sample Urine nicotine and metabolites by LC-MS/MS [1] 

Precipitation protein crash Ease, speed Requires centrifugation, no analyte preconcentration Plasma-free metanephrines by LC-MS/MS [3] 

Solid—liquid extraction Can clean up complex specimens (plasma—serum), can preconcentrate analyte, can be used in multiple modes (ion exchange, hydrophobic, etc.), potential for automation—multiplex in multiwell format Individual solid-phase cartridges are expensive, not all potential interferents are removed, analyte preconcentration may require evaporation—reconstitution step Plasma and urine benadamustine and metabolites by LC—MS/MS [4] 

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