TAS is the abbreviation for Total Analysis System.
It describes a chemical system that automates all for analysis necessary steps. (e.g. sampling, transport, filtration, dilution, chemical reactions, separation and detection)
A new trend today is creating Micro Total Analysis Systems - µTAS. Such a system shall shrink a whole laboratory to chip-size (lab-on-chip). Due to beeing very small such a system can be placed close to a sampling site. It also can be very cost effective thinking of chip technologies, sample sizes and analysis time.
See also: MEMS, analytical chemistry