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All Journal Indonesian Journal of Pure and Applied Chemistry Indonesian Journal of Chemical Analysis (IJCA)
Ruwindya, Yorfan
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Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Environmental Science

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Determination of Ethanol in Vinegar and Beverage by Gas Chromatography: A Validated Method for Halal Verification Rohyami, Yuli; Wijaya, Aprisilia Risky; Ruwindya, Yorfan
Indonesian Journal of Chemical Analysis (IJCA) Vol. 7 No. 1 (2024): Indonesian Journal of Chemical Analysis
Publisher : Universitas Islam Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20885/ijca.vol7.iss1.art5

Abstract

Validation of the method for determining ethanol in vinegar and beverages has been carried out in the linearity range of 0.05-1% using GC-FID. This research was carried out using an internal standard solution and without an internal standard solution. The research aims to validate the linearity of ethanol determination at low concentration levels. This validation is useful to ensure that the ethanol test method in the sample can be detected at low concentration levels. In the halal authentication process, the maximum limit for ethanol content is 5%. The method validation results confirm that in the concentration range 0.05-1% it has good linearity with a correlation coefficient (R) without the addition of internal standards and with the addition of standard solutions being 0.9972 (R2=0.9943) and 0.9952 (R2=0.9905). The results of the analysis of variance (ANOVA) test with a 95% confidence interval and 9 degrees of freedom F-count (0.0141) < F-critical (0.3146) show that the range 0.05-1% corresponds to the limit of linearity. The results of the ANOVA test with a 95% confidence interval with df=6 show the F-test value (0.0879) < F-critical (0.2334) indicating that the two proposed methods have high precision and no significant differences. Both methods also have high accuracy and no significant differences in accuracy as shown by the results of the ANOVA test with a 95% confidence interval and degrees of freedom = 6 showing the F-test value (1.5204) < F-critical (4.2839). It is recommended that the results of this validation be useful in the halal verification process for vinegar and beverage products.
PENENTUAN PROTEIN KASAR PAKAN KUCING KOMERSIAL MENGGUNAKAN METODE KJELDAHL DAN EVALUASI KESESUAIAN INFORMASI LABEL Alhannawi, Miyadah; Rahmadhani, Zahra Putri; Ruwindya, Yorfan; Purbaningtias, Tri Esti
Indonesian Journal of Pure and Applied Chemistry Vol. 9 No. 2 (2026)
Publisher : Tanjungpura University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26418/indonesian.v9i2.104783

Abstract

Protein is a vital nutrient in cat food, supporting growth, tissue maintenance, and physiological functions. This study aimed to determine nitrogen and crude protein contents in commercial cat foods and evaluate their conformity with label claims using the Kjeldahl method. Three dry cat foods representing economy (A), mid-range (B), and premium (C) categories were analyzed according to AOAC 2011.11 through digestion, distillation, and titration, followed by conversion of total nitrogen to crude protein. The average nitrogen contents (±SD) were 5.2887 ± 0.0021%, 5.2817 ± 0.0021%, and 6.1503 ± 0.0023% for samples A, B, and C, respectively, corresponding to crude protein contents of 33.05 ± 0.01%, 33.02 ± 0.02%, and 38.45 ± 0.01%. All measured values exceeded their respective label claims, with deviations of 3.05%, 3.02%, and 0.45% for samples A, B, and C. One-way ANOVA showed significant differences in protein content among samples (p < 0.05). At the same time, one-sample t-tests indicated significant differences between measured values and label claims (p < 0.05). The low %RSD (<0.05%) demonstrated good analytical precision. Overall, higher-priced cat food showed higher crude protein content, while all products exceeded their labeled protein levels and met minimum protein requirements for adult cats.
Co-Authors Alhannawi, Miyadah Rahmadhani, Zahra Putri Tri Esti Purbaningtias Wijaya, Aprisilia Risky Yuli Rohyami, Yuli