Equation 23-3 gives the mass of analyte extracted into a solid-phase microextraction fiber as a function of the partition coefficient between the fiber coating and the solution.
(a) A commercial fiber with a 100-m-thick coating has a film volume of 6.9 × 10-4 mL.26 Suppose that the initial concentration of analyte in solution is cO = 0.10 μg/mL (100 ppb). Use a spreadsheet to prepare a graph showing the mass of analyte extracted into the fiber as a function of solution volume for partition coefficients of 10 000, 5 000, 1 000, and 100. Let the solution volume vary from 0 to 100 mL.
(b) Evaluate the limit of Equation 23-3 as Vs gets big relative to KVf. Does the extracted mass in your graph approach this limit?
(c) What percentage of the analyte from 10.0 mL of solution is extracted into the fiber when K 100 and when K 10 000?