I could have detected up to 10 ppb analyte by electrochemical sensing. In many papers researchers reported lower limit as 15 ppb or 10 ppb and LOD as 0.001ppb or even low?
I know statistical techniques like LOD, LOQ calculations using calibration method, slope, intercept etc but I m confuse where to apply? like I need to apply for serial concentration as 10, 20, 30, 40, 50 ppb vs. current response?
in some methods, i have studied that researchers take 5-7 blank readings than they calculate from this data LOD and LOQ but in this way, one parameter would be constant like concentration would be zero and current response will be varied. With this response data do i need to proceed??? Only this point is confusing which data should i need to take into account? Please guide me.
Thanks in advance.
Dear Noorulain Babar: "....researchers take 5-7 blank readings than they calculate from this data LOD, yes.Certainly, if you have 5 or 7 readings of your blank without analite, you obtain the average (x) and the standard deviation (s). Then LOD will be 3s. But in inhibition biosensors is different (5% Inhibition). In both cases the researchers are not nagree, completely.
Regards
Sir,
Graph / curve will be between Conc. and response(Current). But here in case of blank readings, Conc. will be zero at all only current will be changing maybe in nano-micro range. Kindly elaborate.
Thank you.
Dear Noorulain Babar it does not matter how much low level you are going to achieve you just follow statistiscal techniques by running 5 or 7 readings of blank and you lowest level standard,HPS,LPS and get values and apply stat.
Estimado Noorulain Babar:
Dear Noorulain Babar: if you increase the sensitivity of your registrator you can obtain an significative oscilation over cero. With this oscilations you can calculate Average and SD(s). 10s, it is the determinative limit.
Geetings
Lod is the lowest quantity of a substance that can be distinguished from a blank with stated confidence.
so it can be calculated from the linear plot which is obtained by plotting the graph of different concentration of analyte Vs current in Cyclic voltammogram
LOD= 3.3*(Std Dev. / squire root of N)
where n is the number of tests
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