[Determination of boric acid in biological materials by curcuma paper].

The field of legal medicine has seen a recent increase of poisoning by boric acid and, in cases of emergency, a simple method of making a qualitative analysis of the boric acid content is a necessity. Thus, we have examined curcuma paper (turmeric paper) to see if it can provide a qualitative analysis of the boric acid content in biological materials, so as to identify cases of poisoning. It was found that curcuma paper can provide a preliminary analysis of the quantitative content of boric acid, and that about 0.1 mg/ml of boric acid can be determined. The steps for this testing method follow. First, either blood or urine is acidified with a 6 N concentration of hydrochloric acid, i.e., in the case of urine, 0.5 ml of urine is added to 0.1 ml hydrochloric acid, and for blood, 0.5 ml of blood is added to 0.2 ml hydrochloric acid. If the sample is not sufficiently acidic, more hydrochloric acid is added. Next, a drop of the sample is placed on the curcuma paper and, after drying at room temperature, a red stain results if boric acid is present. (Rosocyanin is formed by the reaction of boric acid and protonated curcumin). Then, a 1 N concentration of sodium hydroxide is dropped onto the stained place, and if rosocyanin is present, the stain will turn blue. Informatively, to make curcuma paper, filter paper (No. 2) is soaked in a saturated curcumin/ethanol solution and then air dried.(ABSTRACT TRUNCATED AT 250 WORDS)