IMPROVEMENT IN THE POLYETHYLENE-GLYCOL CIBACRON BLUE PURIFICATION METHOD

A new approach was developed for the purification of polyethylene glycol (PEG)-Cibacron synthesized from PEG 8000 and Cibacron 3G-A, using an NH2-silica anion exchanger for separation of the unreacted PEG 8000 from the other compounds of the reaction mixture. The adsorption of PEG-Cibacron and Cibacron under acidic conditions (pH 4.7) was 22.4 mg (Cb and PEG-Cb) per gram of silica and 100% elution was achieved with 1% (v/v) ethanolamine solution at pH 9. The silica exchanger can be reused several times without loss of performance. An extraction step with chloroform was used to separate the PEG-dye from the non-bonded Cibacron, which completely partitioned into the aqueous phase. After drying, a dark-blue solid polymer with a yield of 7.6% in relation to the initial mass of PEG was obtained, which is an increase of 50% in relation to earlier work.