Flow injection (FI) on-line sorption separation and preconcentration coupled with atomic (mass) spectrometry using knotted reactors (KRs) for trace element (speciation) analysis is discussed. Compared with FI on-line C18 column preconcentration systems, the KR sorption system permits use of higher sample loading rates to achieve higher concentration efficiencies due to low hydrodynamic impedance in the KR. Moreover, the KR allows the analysis to be conducted at low cost, owing to the long lifetime of the KR and its ease of construction with no need for packing materials, offering a good alternative to conventional C18 column preconcentration systems.

Key words: ATOMIC ABSORPTION SPECTROPHOTOMETRY, MASS SPECTROGRAPHY, PRECONCENTRATION, TRACE ANALYSIS, MORPHOLOGICAL ANALYSIS, ON-LINE ANALYSIS, FLOW INJECTION ANALYSIS, SEPARATION