Volume 37 Number 4 LABMEDICINE 233 Over the last years capillary zone electrophoresis has emerged as a powerful tool for the separation of proteins and other biopolymers, 1 including serum protein fractions. 2 In clinical use, it allows the detection of monoclonal immunoglobulins (MCs). In comparison to traditional electrophoretic methods, Paragon CZE (Beckman Coulter, Fullerton, CA) offers several advantages: automation, high resolution, 3,4 and faster turnaround time. 5 More recently, a new

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... pillary electrophoresis instrument has been developed by Sebia (Capillarys, Sebia, Issyles-Moulineaux, France). Considering the importance of automation and reproducibility of serum electrophoresis, we compared the analytical performance of the 2 instruments: Paragon CZE and Capillarys. As a further goal, we evaluated the ability of MCs (n=175) detection of both instruments. Materials and Methods Instruments The Paragon CZE system basically consists of a sample unit which accommodates the primary tubes and a phoresis chamber equipped with 7 fused silica capillaries (20 cm in length and 25 µm inner diameter). Proteins are measured by direct absorption at 214 nm through a small optical window in the capillary. The sample carousel consists of 10 sectors each containing 7 primary tubes and 1 segment with 7 traps for dilutions. 4 The protein separation occurs in 4.3 min, at 10.3 kV and 24°C. 5 The software version used was 1.6.02, with modified buffer and more efficient cooling, with respect to the previous versions. Capillarys instrument includes a flowing tape for sample handling, a system of 8 fused silica (17 cm in length and 25 µm inner diameter) capillaries arranged in parallel for the analysis, and a computer with software (4.41 version) for the management of operation and results. Ultraviolet detection at 200 nm is used for protein quantification. The system is provided with sample racks for the primary tubes and segment for dilutions, each consisting of eight traps. The electrophoretic migration occurs in 2.30 min at 9KV and 35°C. The temperature is controlled by Peltier's effect. Both instruments were used as indicated by the manufacturer. Science Figure 3_Detection limit of monoclonal component. Electropherogram of an undiluted MC sample showing a peak in the γ γ-region in A and in C, and diluted sample (1:32) corresponding to 0.4 g/L of MC in B and D obtained with Paragon (A, B) and Capillarys (C, D), respectively.