Samples/properties	MSP-PEG-COOH prepared with Mal-PEG-Mal-400	MSP-PEG-COOH prepared with Mal-PEG-Mal-800	MSP-PEG-COOH prepared with Mal-PEG-Mal-4000	MSP-PEG-COOH prepared with Mal-PEG-Mal-6000
Size by laser-scattering (μm)	0.89	0.69	0.55	0.51
SAV-CIAP binding capacity(mg · g−1)	0.02	0.30	0.55	0.50
Carboxyl groups (mmole · g−1)	0.25	0.23	0.19	0.16

Notes: Sizes and quantities of carboxyl groups showed coefficient of variation below 12% from duplicated assays. Just one monomer at 4.0 g was used in each microemulsion system.

Abbreviations: CIAP, calf intestinal alkaline phosphatase; MSP, magnetic submicron particle; PEG, poly(ethylene glycol); SAV, streptavidin.