TECHNIQUE: LIGHT MICROSCOPY, PHASE CONTRAST
ANALYTE: fibers (manual count)
SAMPLE
PREPARATION: acetone - collapse/triacetin - immersion
method [2]
COUNTING
RULES: described in previous version of this
method as “A” rules [1,3]
EQUIPMENT: 1. positive phase-contrast microscope
2. Walton-Beckett graticule (100-µm field
of view) Type G-22
3. phase-shift test slide (HSE/NPL)
CALIBRATION: HSE/NPL test slide
RANGE: 100 to 1300 fibers/mm² filter area
ESTIMATED LOD: 7 fibers/mm² filter area
PRECISION ( ): 0.10 to 0.12 [1]; see EVALUATION OF
METHOD