US EPA

6649807 

Journal Article 

DETERMINATION OF FREE ACID IN FERRIC-CHLORIDE SOLUTION (REINVESTIGATION OF JIS-K-1447) 

Sahara, M; Yoshimura, H; Sagara, F; Ueno, K; Yoshida, I; Ishii, D; , 

1992 

1 

Bunseki Kagaku / Analysis Chemistry
ISSN: 0525-1931 

JAPAN SOC ANALYTICAL CHEM 

TOKYO 

T45-T47 

WOS:A1992HH94400011 

Acidic ferric chloride solution is widely used as an etching solution for processing the copper coated printed circuits. Determination of free acid (HCI) in ferric chloride solution according to the JIS K 1447 method often results in a large negative errors. Principle of the JIS method involves the preliminary separation of ferric ion as K3FeF3 by adding a neutralized potassium fluoride,solution, followed by the alkalimetry on an aliquot of the filtrate. However, it was found that hydrofluoric acid which results in the mixture after the addition of potassium fluoride, reacts with glass-ware with the consumption of proton, thus giving negative errors. Accordingly, all glass-wares which come in contact with acidic potassium fluoride solution, have been replaced with polypropyrene laboratory wares. The analytical results obtained under this condition was in good agreement with the calculated values.