Abbreviation for "total ionic strength adjustment buffer". It is recommended for ground waters, potable waters, urine, etc. TISAB buffers the solution at pH 5.0-5.5 to avoid hydroxide interference or the formation of hydrogen complexes of fluoride. It contains DCTA (1, 2 cyclohexylene diaminetetra-acetic acid) to preferentially complex any aluminum in the sample. It also provides a constant high ionic strength background to "swamp out" differences in sample ionic strength.
