<![CDATA[Standar antioksidan seperti asam galat, asam askorbat dan Trolox® sering digunakan pada penentuan kapasitas antioksidan, konsentrasi standar optimum sangat diperlukan untuk menentukan kurva regresi linier yang memenuhi hukum Lambert-Beer. Tujuan penelitian ini adalah untuk menentukan konsentrasi optimum masing-masing standar dalam membuat kurva regresi linier dengan nilai absorbansi 0,2-0,8. Metode pengujian dilakukan secara kuantitatif mencari nilai absorbansi dengan mereaksikan masingmasing standar terhadap radikal Bebas DPPH (2,2-diphenyl-1-picrylhydrazyl) 0,1 mM menggunakan spektrofotometer. Pengamatan dilakukan sebanyak 2 kali, data yang diperoleh disajikan dalam bentuk tabel, grafik, nilai absorbasi rata-rata dan standar deviasi. Hasil pengamatan menunjukkan bahwa masing-masing standar memberikan kurva regresi linier dengan rentang nilai optimum pada asam galat (2,5; 5; 10; 15 mg/L), asam askorbat (10; 20; 30; 40; 50; 60; 70 mg/L) dan Trolox® (10; 20; 30; 40; 50; 60 mg/L). Berdasarkan hal tersebut dapat disimpulkan bahwa asam galat yang paling efektif dalam mereduksi radikal Bebas DPPH 0,1 mM dibandingkan asam askorbat dan Trolox®.Kata Kunci : asam galat, asam askorbat, Trolox®, antioksidan, DPPH (2,2-diphenyl-1- picrylhydrazyl)AbstractAntioxidant standard such as gallic acid, ascorbic acid, and Trolox® often are used to determine of antioxidant capacity, standard optimum concentration are needed to make regression of curve to follow of Lambert-Beer law. The purpose of this research is to determine of optimum concentration each standards to make regression of curve with absorbance value 0,2-0,8. The quantitative methode was done to search absorbance value by reaction between each standards to free radical of DPPH (2,2-diphenyl-1- picrylhydrazyl) 0,1 mM by spectrophotometer. The experiment was done two replicates, all of datas were collected is showed on table, graph, absorbance value average and deviation of standard. The result show that each standards gave regression of curve by optimum interval of value respectively; gallic acid (2,5; 5; 10; 15 mg/L), ascorbic acid (10; 20; 30; 40; 50; 60; 70 mg/L) and Trolox® (10; 20; 30; 40; 50; 60 mg/L). The conclution of this researh is gallic acid is the most efective to against of free radicals DPPH 0,1 mM to compare with ascorbic acid and Trolox®.Kata Kunci : gallic acid, ascorbic acid, Trolox®, antioxidant, DPPH (2,2-diphenyl-1- picrylhydrazyl)]]>
