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Journal : Science and Technology Indonesia

Determination of (+)-Catechin and Antioxidant Activity in Faloak (Sterculia quadrifida R. Br) Stem Bark Infusion Audrey Gracelia Riwu; Jusak Nugraha; Djoko Agus Purwanto; Erwin Astha Triyono
Science and Technology Indonesia Vol. 8 No. 1 (2023): January
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2023.8.1.59-65

Abstract

Oxidative stress is a condition that can damage human cells and tissues and has been linked to a number of illnesses, including cancer, cardiovascular disease, autoimmune disorders, and neurological diseases. Oxidative stress conditions can be brought on by pollution, radiation exposure, and an unhealthy lifestyle. Antioxidants are substances that can be used to both prevent and treat oxidative stress. This study aimed to identify and quantify (+)-catechin levels and antioxidant activity of the stem bark of Sterculia quadrifida R. Br extracted by the infusion method, a method similar to traditional medicine processing generally in the community. Determination of (+)-catechin and antioxidant activity of S. quadrifida were evaluated by HPLC and DPPH assay, respectively. Quantification of (+) catechin content by HPLC system with wavelength 280 nm and antioxidant activity by spectrophotometry method with wavelength 517 nm. The results show that the mean value of (+)-catechin level was 7.786% and the IC50 value of the antioxidant activity was 51.5 ug/mL having a moderate antioxidant activity category. S. quadrifida stem bark infusion can be utilized as a medication candidate for the prevention or treatment of a variety of disorders caused by oxidative stress.
Development and Validation GC/MS Method for Methamphetamine Analysis in Urine by Miniaturization QuEChERS Soraya Aulia; Riesta Primaharinastiti; Djoko Agus Purwanto
Science and Technology Indonesia Vol. 8 No. 3 (2023): July
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2023.8.3.451-460

Abstract

This paper explains the development of a quick and easy gas chromatography (GC) approach to identify methamphetamine in urine. This research used gas chromatography with mass spectroscopy and a capillary column TG-5SILMS (5% phenyl methyl siloxane, 30 m x 0.32 x 25 m). The carrier gas flow rate was set at 1.0 mL/minute, the temperature inlet and detector had been set at 300°C, and the oven temperature was programmed to initiate at 50°C and held for 1.5 minutes before being raised to 300°C at a rate 40°C/minute and held for 3 minutes. Sample pre-treatment by modification of the QuEChERS method includes using a relatively large amount of inorganic salt, extraction volume and extraction cycle. The optimal conditions for processing a 400 uL urine sample were 160 mg magnesium sulphate, 40 mg sodium chloride, and 400 uL acetonitrile for organic solvent. According to the validation test, the detection limit for methamphetamine was 0.36 ug/mL; the quantitation limit was 1.09 ug/mL, and the calibration curve followed the regression line. y=1.0489x-3.7914, coefficient (r) was 0.9973. The recovery of the analyte spiked into urine at 5, 7 and 9 ug/mL on average was 100.5±2.33% for intraday dan 93.3±7.21% for interday. The precision was excellent, with an average coefficient of variation of 2.31%. The procedure was applied to four urine samples from drug users and the first abuser (25.51 ug/mL), the second abuser (15.05 ug/mL), the third abuser (17.72 ug/mL) and the last abuser (3.08 ug/mL) were all satisfactorily quantitated.