Standard Operating procedure for estimation of BORON in Pharmaceutical and scientific labs.
Principle:
When Azomethine-H, which comes from condensation of H Acid (8-amino-naptha-1-ol-3.6-disulphonic Acid) and Salicyladehyde, reacts with borate in a watery solution with a pH higher than 6, it a yellow complex that we can measure using a spectrophotometer. To understand the yellow complex We look at how much light it absorbs, especially between 410 nm and 420 nm.
Steps for estimation of Boron:
Materials/ Reagents:
Pure water without boron
Azomethine H Solution: Mix 1.0 gm Azomethine H sodium salt and 3.0 gm L ± Ascorbic acid in a 100 ml bottle, and fill it with water. The solution remains stable when it is stored in a polyethylene bottle for a week at a temperature of 4ºC to 6ºC.
Borate stock: Dissolve 5.719 gm boric acid in 1000 ml water. Keep it in a bottle with a label. Strength 1 ml = 1.0 mg of borate.
Standard Borate: Mix 10 ml stock with 1000 ml water. Keep it in a bottle with a label. (Strength 1 ml = 10µm Borates as B)
Boron Solution: Mix 10 ml stock with 100 ml water. Keep it in a bottle with a label. (Strength 1 ml = 1.0µ Borates as B).
Related: SOP for Estimation of Mercury
Procedure for estimation of BORON:
Make 0.5, 1, 2, 4, and 5 ppm of borate from the standard solution (1 ml = 1 µ of borate). Take 25 ml of each, standard sample and Distilled water as a blank in a 100 ml Volumetric flask. Add 10 ml azomethine H to each. Keep at 20ºC ± 1ºC for 2 hrs in the dark, then make up to 100 ml with water. Measure the highest absorbance.
Calculation:
Boron, mg/L =
ABS (Spl) – Absorbance of sample
SLOPE – Slope from the standard curve
Reference: IS: 13428 – 1998.”
This method estimates boron levels using specific chemical reactions and measurements.
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