All of our ready-to-use buffers are: – Conveniently packaged. – Prepared fresh for each order. – Economical and time-saving. – Desired pH should be specified when ordering. The buffer is a vehicle for the fixative and requires certain properties: 1-To maintain constant pH during the time of the fixation. The pH of the fixative in EM is adjusted using the buffer system chosen; e.g. range 6.5-8.0. 2-The ionic constitution to prevent the extraction of cellular components, or the deposition of precipitates of fixative chemicals.