ABSTRACT
This chapter discusses advances in laboratory filtration materials and practices, mainly since 1960. This period has seen refinements in application of the time-tested collodion membrane filter, especially in the biological areas of analyses, and also many new uses in sampling air and waterborne particles. The development of the polycarbonate filter has extended the limits of research capabilities and provided more precise means of correlating theory with practice. Silver membrane filters have now been produced that allow the sampling of micrometer and submicrometer particles on a metal matrix. The sophisticated analytical procedures involved in detecting trade chemicals have leaned heavily on the membrane filter to concentrate the small number of suspended particles present in large volumes of fluids. Ceramic and glass materials have been tested and proved useful in methods requiring inert, temperature-resistant media. Cytological examination with membrane filters is performed on blood and urine; spinal, pleural, bursal, pericardial, and ascitic fluids; and colon and gastric washings.
