Turmeric rhizome is a source of natural yellow pigment which can be applied as a pH indicator. This pigment was extracted from turmeric rhizomes using ethanol as a solvent. The purpose of this study was to examine the application of turmeric rhizome pigment extract (TRPE) as an indicator to determine the concentration of H+, the precision and accuracy of the use of TRPE as an indicator of acid base titration. As a comparison, in this study used also a standard indicator, such as phenolphthalein (PP) and methyl red (MR). Titration was carried out on samples without spike and spike samples. The result showed that the rendement of TRPE was 35.72%. The concentration of H+ on the sample without spikes in the titration of strong acid-strong base (SASB) and strong acid-weak base (SAWB) using TRPE, PP and MR indicators gave the same result, namely 0.041 M. The concentration of H+ on spike samples in SASB and SAWB titrations using TRPE, PP and MM indicators gave the same result, namely 0.165 M. The use of TRPE in the titration of SASB, SAWB, weak acid-strong base (WASB) and weak acid-weak base (WAWB) provided good precision with the coefficient of variation (CV) obtained in the titration of samples without spikes and titrations of spike samples, respectively are 1.2% and 0.35%, but only give good accuracy in SASB and SAWB titration with the recovery in the range of 102.3%-102.7%.Keywords: accuracy; acid base; precision; titration; turmeric ABSTRAKAplikasi Pigmen Rimpang Kunyit Sebagai Indikator Titrasi Asam-BasaRimpang kunyit merupakan salah satu sumber pigmen kuning alami yang dapat diaplikasikan sebagai indikator pH. Pigmen ini diperoleh dengan cara mengekstraksinya dari rimpang kunyit menggunakan pelarut etanol. Penelitian ini bertujuan untuk  mengkaji aplikasi ekstrak pigmen rimpang kunyit (EPRK) sebagai indikator untuk menentukan konsentrasi H+ dalam sampel, presisi dan akurasi dari penggunaan EPRK sebagai indikator titrasi asam basa. Sebagai pembanding maka dalam penelitian ini digunakan pula indikator standar yakni fenolftalin (PP) dan metil merah (MM). Titrasi dilakukan terhadap sampel tanpa spike dan sampel spike. Berdasarkan hasil penelitian diperoleh rendemen EPRK sebanyak 35,72%. Konsentrasi H+ dalam sampel  tanpa spike pada titrasi asam kuat-basa kuat (AKBK) dan asam kuat-basa lemah (AKBL)  menggunakan indikator EPRK, PP dan MM memberikan hasil yang sama yaitu 0,041 M.  Konsentrasi H+ dalam sampel  spike pada titrasi AKBK dan AKBL menggunakan indikator EPRK, PP dan MM memberikan hasil yang sama yaitu 0,165 M.  Penggunaan EPRK dalam titrasi AKBK, AKBL, asam lemah-basa kuat (ALBK) dan asam lemah-basa lemah (ALBL) memberikan presisi yang baik dengan coefficient of variation (CV) yang diperoleh  pada titrasi sampel tanpa spike dan titrasi sampel spike berturut-turut adalah ˂ 1,2%  dan  ˂ 0,35%, tetapi hanya memberikan akurasi yang baik pada titrasi AKBK dan AKBL dengan recovery yang diperoleh adalah pada kisaran 102,3%-102,7%.Kata Kunci: akurasi; asam basa; presisi; titrasi; kunyit

Research has been carried out to examine the extraction and application of purple sweet potato tuber extract as an indicator of acid-base titration. Purple sweet potato tuber extract was obtained by extracting fresh tubers using ethanol 95% medical grade (PSPTE-95%) and ethanol 96% analytical grade (PSPTE-96%). Three variations of the maceration stage extracted samples. The extract was used for a phytochemical test and applied as an indicator for acid-base titration. Based on the research conducted, the rendement extract was extracted by ethanol 95% medical grade (PSPTE-95%) for the three stages of maceration are 4.34%, 4.76%, and 5.64%, the rendement extract was extracted by ethanol 96% analysis grade (PSPTE-96%) for the three stages of maceration are 7.09%, 12.16%, and 20.43%. PSPTE-95% and PSPTE-96% contain flavonoids, tannins, alkaloids, and saponins. PSPTE-95% and PSPTE-96% can be applied as indicators for titration of HCl solution with NaOH solution and HCl solution with NH4OH solution.