Hi guys, i want to ask you something. I'm doing some study on antioxidant activity in Palm Kernel Cake (PKC) by using DPPH assay method. I observed that my the color of my bio-oil extracted from PKC was appeared in likely clear colour. Last time, I saw someone wrote that it's better to use 0.1mM of DPPH instead of 0.6mM of DPPH for a clear solution sample. Is that true? Can someone give me some opinion how can i know how much concentration for dpph i should use? It's okay if I use 0.6mM DPPH? Thankyou. 😁
I prepared the DPPH solution by mixing 0.005 g of DPPH powder with 200 ml of ethanol (96%). And to know if the concentration was right, I used to read the solution in the spectrophotometer at 517, if my memory is good, it has to be
Hi there,
The DPPH assays for antioxidant activity do indeed show variability in the absorbance thresholds used in different studies. Some researchers prefer using an absorbance value below 1 (DPPH 0.6mM) for a gradual color change, while others recommend a threshold of less than 0.7 (DPPH 0.1mM) for a quicker and more pronounced response.
When considering the absorbance thresholds for DPPH assays, it is crucial to be aware that the literature may present variable protocols. Parameters such as λmax, used for absorbance measurements, typically range between 515nm and 520nm, and the reaction time can vary from 30 to 5 minutes.
Article Genesis and development of DPPH method of antioxidant assay
To ensure reliable comparisons, you should assess the antioxidant activity of your bio-oil alongside well-established antioxidants like ascorbic acid, quercetin, or beta-carotene among others. These compounds are widely recognized and commonly used as reference standards in antioxidant studies.
Ultimately, the choice depends on the experimental objectives and sensitivity requirements of your study.
Best of luck 😁
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