Mosa Elhady Osman

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Questions related from Mosa Elhady Osman

What are the possible compounds having absorbance 0.58 at 275 nm (lamba max) ,266.5, 257.5 nm?

On TLC the compound have yellow- green color in day light and yellow fluorescence at UV light 365 nm. Its Rf =0.4.mobile phase (toluene:ethylacetate:formic acid)5:4:1, silica gel is stationary phase

25 April 2016 6,797 3 View

Is it stable to use tolune:ethylacetate:formic acid as eluent with silica gel open column?

When I use this eluent , the top layer of silica gel converted to gel state.

19 April 2016 9,533 5 View

What are mobile phases suitable to elute polar cpds remain at baseline using TLC?

I use hexane:ethylacetate:dichloromethane(3:7:2) but resolved well. Sample is methylene chloride fraction

07 April 2016 5,169 5 View

What is the meaning of negative % when calculating RSA% using DPPH method?

When I calculate RSA% using DPPH method I find negative % e.g. - 80%, -18%.

01 June 2015 442 12 View

How can I calculate %RSA (radical scavenging activity) using DPPH method?

I need formula for calculating %RSA using DPPH method

31 May 2015 4,211 22 View