Acid-base indicator: hydroalcoolic extract of the flower of species Macroptilium lahyroides (L.) Urb

Abstract

The Macroptilium lathyroides (L.) Urb emerges as raw material for obtaining an hydroalcoholic extract that can be used as an identifier of acids and bases in daily life. The objective of this work was to obtain the alcoholic extract from the crude mass of M. lathyroides (L.) Urb petals and use it as natural acid-base indicator. It is a qualitative research, the experimental methodology of the present work was developed in fives: (i) development of a pH range (0-14), (ii) obtainment of a pH paper from the alcoholic extract, (iii) identification of acid and base substances used in daily life with the extract and pH indicator paper (iv) determination of acetic acid in commercial vinegars, and (v) comparison with a synthetic indicator (phenolphthalein). For all the steps, the hydroalcoholic extract of M. lathyroides (L.) Urb was efficient, obtaining excellent results. In this way, the obtainment of the extract and pH indicator paper has a low cost and can be used as an acid-base indicator, being a feasible option for synthetic indicators, since those have a high commercial value.