ABSTRACT
Herein, highly defined monolithic beds were prepared in glass microchips by photopolymerization of ethylene glycol methacrylate phosphate (EGMP), acrylamide, and N,N'-methylenebisacrylamide (BAA) using an epifluorescence microscope as UV-irradiation source. Such a fast and easy method allowed precise control of (i) the edge shape, (ii) the location along the microchannel, and (iii) the length of the monolithic plugs within glass microchips. The addition of hydroquinone, a polymerization inhibitor, to the prepolymerization mixture was beneficial for achieving local and robust incorporation of monoliths with sharp edges within microchannels. The monolith length was easily tuned from 160 to 400 µm through simple change in the magnification of the objective and was found to be repeatable (relative standard deviation <7.5%). Further application for on-chip monolith-assisted solid - phase extraction is demonstrated for fluorescently labeled peptide. Both binding and subsequent elution behaviors were found to fully agree with a cation-exchange mechanism in concordance with the presence of phosphate groups at the monolith surface. Graphical abstract In-chip microscope-UV-synthesis of monolithic plugs with sharp edges.
Subject(s)
Glass , Microscopy/methods , Peptides/chemistry , Polymers , Ultraviolet Rays/adverse effects , PorosityABSTRACT
Objective To develop SPE - HPLC method for the assay of paeonol in Liuwei Dihuang Pill (LDP). Methods Separation was performed on a Hypersil ODS(2) column (250 mm?4. 6 mm, 5?m) . The mobile phase consist of methanol - 2 % acetic acid (55 :45, v/v) . The flow rate was 1 mL/min. The UV detection was set at 275 nm. Results Paeonol had a good linear relation in the range of 0. 03998 ~ 0. 7996 ug, the average recovery of honeyed bolus of LDP was 102. 9 % and the RSD was 1.2%; the average recovery of concentrated bolus of LDP was 101. 5 % and the RSD was 1.8%. Conclusion The method is simple, sensitive and rapid and it can be used to determine the paeonol content of LDP.
