Sri Retno Dwi Ariani
Bachelor Program of Chemistry Education, Faculty of Teacher Training and Education, Universitas Sebelas Maret, Indonesia Jl.Ir Sutami No 36 A, Surakarta, Central Java

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Analysis of The Nature of Science in Chemistry Textbooks on The Topic Acid-Base Equilibrium: a Content Analysis Aulia Rahmah; Sri Retno Dwi Ariani; Bakti Mulyani
JKPK (Jurnal Kimia dan Pendidikan Kimia) Vol 7, No 3 (2022): JKPK (Jurnal Kimia dan Pendidikan Kimia)
Publisher : Program Studi Pendidikan Kimia FKIP Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/jkpk.v7i3.65094

Abstract

This study was conducted to describe aspects of the Nature of Science (NoS), its presentation, and its scores from chemistry textbooks used in Surakarta on acid-base equilibrium topics. This research was qualitative research with a content analysis method. Three high school chemistry textbooks for class XI from different publishers were analyzed by two raters based on ten aspects of the NoS. Interrater reliability was calculated using the cohen Kappa. The results showed that a scientific law is the only aspect that is not included in the three textbooks A, B, and C. Other aspects of NoS contained in textbooks A and B are slightly different from textbook C. Textbooks A and B contain the same aspects: empirical, inferential, creative, theory-driven, tentative, scientific methods, scientific theories, social science, and the application of science in socio-cultural, while textbook C does not contain tentative and theory-driven aspects. The implicit-correct category dominates the presentation of the NoS aspects in the textbooks. Presentations with implicit-incorrect and explicit-incorrect categories were not found in this study. The scores obtained by textbooks A, B, and C based on the presentation of aspects of NoS are 9, 11, and 8, respectively, of the maximum total score that can be obtained of 30. It did not show the presence of the NoS aspects explicitly, correctly, consistently, and completely, so textbooks containing NoS explicitly are required. Teachers also need to guide students in interpreting NoS in learning. 
pH-Sensitive Strips Based on Cellulose and Anthocyanins from Dried Java Plum Fruits (Syzygium cumini) Muhammad Hizbul Wathon; Endang Susilowati; Sri Retno Dwi Ariani
JKPK (Jurnal Kimia dan Pendidikan Kimia) Vol 8, No 1 (2023): JKPK (Jurnal Kimia dan Pendidikan Kimia)
Publisher : Program Studi Pendidikan Kimia FKIP Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/jkpk.v8i1.72702

Abstract

This study aimed to develop pH-sensitive strips made of cellulose incorporated with anthocyanins extracted from dried Java plum fruits (Syzygium cumini) which potentially can be used to monitor food freshness. The spoilage of animal protein typically produces total volatile basic nitrogen (TVB-N), which can be easily detected using pH-sensitive indicators. pH-sensitive indicators can be developed by combining biopolymers and anthocyanins. Biopolymers were cellulose from Whatman filter paper. While anthocyanins in this study were extracted from dried Java plum fruits (Syzygium cumini) with acidified water (0.01% v/v HCl) followed by SPE. Anthocyanins were incorporated into Whatman filter paper and dried at 70 °C for 10 min. Cellulose incorporated with anthocyanins was analysed using FT-IR and tested for pH 7-10. LC-MS spectra showed cyanidin-3-O-glucoside (m/z 449.3), delphinidin-3-O-glucoside (m/z 465.3), and petunidin-3-O-glucoside (m/z 479.3). These anthocyanins were the products of the deglycosylation of anthocyanin diglycosides. The deglycosylation of anthocyanins takes place through two different routes in either hemiketal or quinonoid forms. Those proposed two pathways are through protonation on an oxygen atom connecting an aglycone and a sugar moiety or through protonation on an oxygen atom within a sugar ring moiety. UV-Vis studies showed the colour profiles of anthocyanins in buffer solutions pH 1-12. The λvis-max of flavylium at pH < 3 ranged from 515-524 nm. At pH 4 to 6, colourless hemiketal was observed. The λvis-max of the quinonoid base was 575 nm at pH 7 and 590-599 nm for quinonoid anion at pH > 8. In alkaline pH, chalcone was observed.