[ElPogito11]

Hi All! I have a question regarding the new formula for % LFM recovery given on the 23rd edition of standard methods on examination of water and waste waters. The exact formula shown there is

% LFM Recovery = LFM conc x (spike vol + sample vol) - (sample conc x sample vol)   x 100
                                                            spike solution conc x spike vol

What is the difference between LFM conc and spike solution conc?