Glass fibre filter
In one part of the glass filter total soluble Cr was
determined by atomic absorption spectroscopy after
water extraction. Soluble Cr III was separated from
soluble Cr VI in a column filled with s-diphenylcarbazide
resin, which retains Cr VI. Soluble Cr III was
determined in the eluate. After alkaline extraction of
the sample, insoluble Cr VI was determined in the
insoluble residue by a colorimetric method with s-