BS ISO 6849:1996

This standard BS ISO 6849:1996 Photography. Processing wastes. Determination of boron is classified in these ICS categories:

• 37.040.30 Photographic chemicals

This International Standard specifies two methods for the determination of boron in photographic processing wastes. The first method is the estimation of borates by titration of the boric acid-mannitol complex, which is a stronger acid than the boric acid from which it is formed. It is suitable for boron concentrations of 0,1 mg/l and higher. In the range 0,1 mg/l to 5 mg/l, phosphate is removed by precipitation by lead acetate. In the range 1 mg/l to 100 mg/l, the sample is diluted 25 times; this eliminates phosphorous interference if the phosphorous concentration is below 500 mg/l.

The second and alternative method is a spectrophotometric technique using methylene blue and is useful in the boron range of 0,1 ml/l to 1,0 mg/l, this being the concentration likely to be encountered in photographic processing wastes.