This book provides a systematic description of a series of analytical separation techniques that can be regarded as intermediate alternatives between batch manual and chromatographic techniques. Their ease of automation and miniaturization, flexibility for on-line coupling to most available analytical instruments and high potential for the resolution of real problems in the clinical, pharmaceutical, industrial, environmental and nutritional fields endows them with increasing relevance, as apparent from the recent increase in publications devoted to these techniques and the growing availability in commercial equipment.