I prepared solution of ABTS and I don,t know how long it can be used.
- ABTS with persulfate
- ABTS without persulfate.
Thanks
This is published in
Evaluation of antioxidant activity using peroxynitrite as a source of radicals.
Geletii YV, Balavoine GG
Methods in Enzymology, 31 Dec 2001, 359:366-379 DOI: 10.1016/s0076-6879(02)59199-0
ABTS is available from Sigma and can be used without additional purification.
ABTS + is synthesized easily by oxidation of ABTS with solid PbO2. Dissolve
50 mg of ABTS in 50 ml of phosphate buffer solution (75 mM, pH 7.0) and then
under agitation add 150-220 mg of PbO2 (7- to 10-fold excess over ABTS). The
solution immediately becomes blue-green. After 2-3 min of agitation, thoroughly
remove all powder from the solution using a fine filter. Reaction time may vary
depending on the surface area of PbO2. ABTS conversion to ABTS + should be
~20-30%. If it is higher, ABTS + slowly decays and in several hours its concentration
reaches the value corresponding to 20-30% conversion. ABTS + can be quantified
by measuring its absorbency at 660 nm, e = 1.2 x 104 mo1-1 liter cm -1.
Its concentration should be checked before and after use. ABTS + stock solutio
ns (-0.5 mM) are rather stable at ambient temperature. The ABTS+/ABTS mixture irreversibly precipitates at < 10 °C.
Regardless of what previous publication recommend, you should always test it by yourself by measuring the absorbance of the ABTS+PSA solution at 734 nm and/or making a scan reading of the solutions. By doing so, you have experimental evidence that the solutions are OK or not.
Daniel Carneiro Moreira What is PSA, Prostate-specific antigen ? Why do you need to record the absorbance of the ABTS+PSA solution? Why not to check the absorbance of ABTS alone solution?
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