I extracted phosphate from my sample using a sodium bicarbonate solution. When I acidify the sample to a very low pH, I see that the color development (using ammonium molybdate and ascorbic acid) takes longer than when I directly add the reagents to the extract without acidification. However, I understand that when I add the reagents without acidifying, carbon dioxide is produced due to the presence of bicarbonate.
In this case, would it be more ideal to adjust the sodium bicarbonate solution to around pH 6-8? I read somewhere that this is the ideal sample pH.