Development of microprefilter for chromatography column in HbA1c assays

The complexity of blood and its matrix in high-performance liquid chromatography (HPLC) glycated hemoglobin (HbA1c) assays is closely related to column performance. However, the available prefilters with a single structure or surface membrane materials are not ideal for column protection, and coupled with the complexity of blood samples, leads to rapid degradation of column performance. Therefore, we have developed a new microprefilter with a three-stage filtration design and depth filter material to protect the column. All filter materials used in the preparation of microprefilters were characterized, screened, and optimized, and then manufactured on the basis of optimized filter materials, which are depth filter material microprefilters. Based on the material and structural design, microprefilters were capable of filtering particulate matter from test samples on a step-by-step basis to avoid the plugging effect that occurs when all sizes of substances are gathered together. Moreover, all newly developed microprefilters can be tested more times, up to 600 times. Microprefilters with small-pore-size final filtration membranes of polyethersulfone, hydrophilic polytetrafluoroethylene, and mixed cellulose showed excellent column protection in terms of column efficiency, HbA1c retention time, number of column tests, and column backpressure, and prolonged column lifetime by as much as 20-30% compared with microprefilters with large-pore-size final membranes. Our study provides valuable depth filter material microprefilters with multistage filtration for chromatography columns, and showed excellent column protection and prolonged column lifetime. Meanwhile, microprefilters can be tested more times. The newly developed microprefilters with a small-pore-size final membrane are the optimal choice for column protection of the HbA1c assay.