Colorimetric Determination of Boron in Aqueous Solutions and in Borosilicate Glass by Solvent Extraction

Boron has been determined in steel (1), in soils (2), and in natural waters (3) colorimetrically by extract-ing methylene blue fiuoroborate with 1, 2 dichloro-ethane. Recently (4) a modification of this method was employed to determine boron in thin films of pyro-lyt ical ly deposited borosil icate glass. The details and short discussion of the procedure are presented here. Sample Preparation (i) If necessary, the boron-containing sample is dis-solved in a measured amount of H20 and diluted to the range 1-4 ~g B/ml. (ii) To a 30 ml polyethylene dropping bottle (A. H. Thomas, No. 2247-S) 2.0 ml of the solution made in step (i), 2.0 ml dilute HF (DHF:50 ml 50 % HF/I H20), and 3.0 ml 0.001M methylene blue solution (MBS