Automated chemiluminescence immunoassay for a nonionic surfactant using a recycled spinning-pausing controlled washing procedure on a compact disc-type microfluidic platform

• CL flow immunoassay for a nonionic surfactant has been performed on a CD-type microchip.
• Washing efficiency of a surface of the microchip has been enhanced by using a rotation program.
• The proposed method has a function of sequential injection analysis by controlling rotation speed.

A fully automated and integrated chemiluminescence immunoassay, carried out on a compact disc (CD)-type microfluidic platform, for the detection of alkylphenol polyethoxylates (APnEOs) is described. The pattern of the CD-type microchip was designed so as to permit the sequential solution delivery of the sample solution, the washing solution and the luminol solution, which are required in the chemiluminescence immunoassay process, along with a designed rotation program for spinning the CD-type microchip. The procedure for flowing the washing solution, the volume of which was limited on the CD-type microchip, was optimized by using a recycled spinning-pausing rotation program to overcome the non-specific adsorption of the horseradish peroxidase labeled APnEOs at the detection area. The detection limit of the immunoassay is about 10 ppb.