Flow injection analysis for simultaneous quantification of prolactin concentration and glycosylation macroheterogeneity in cell culture samples.

A flow injection analysis (FIA) system is presented for a twostep immunoassay-based determination of the total humanprolactin (hPRL) concentration along with its degree ofglycosylation. Separate measurement of total hPRL and nonglysosylated human prolactin (nG-hPRL) were made using twoflow-through cartridges each containing immobilized antibodiesof different specificity. The antibodies are immobilized on thesurface of a carrier. Glycosylated hPRL (G-hPRL) and, thus, thedegree of glycosylation were calculated by the differencebetween the two specific determinations. Enhanced specificityfor the determination of nG-hPRL was obtained using unfavorablebinding conditions through incorporation of alkaline pH andchaotropic agents into the carrier/dispersion buffer. The assayfor total hPRL and nG-hPRL were each found to be linear withinthe relevant concentration range. The results of the two-stepFIA method were found to agree with those obtained by thestandard methods of ELISA and western blotting while offeringthe advantage of minimal analysis time (10 min) and eliminationof manual manipulations.