TECHNOLOGY FOCUS - POLYMERS - Preferred Cell: In the cell made of polymers for spectra measurement, where, in the region composed of the polymer chain, the ratio in oxygen to carbon and the ratio in nitrogen to carbon determined by X-ray photoelectron spectroscopy (XPS) are both greater than or equal to 0.01. The region composed of the polymer chain includes an analysis light-permeable region on the cell inner surface and, in the analysis light-permeable region, the ratio in oxygen to carbon and the ratio in nitrogen to carbon determined by X-ray photoelectron spectroscopy (XPS) are both greater than the value obtained in the region on the cell surface in which the analysis light would not permeate by greater than or equal to 0.01. The cell made of polymers for spectra measurement comprises a bottom wall, side walls provided upward in a vertical direction from the periphery of the bottom wall, and an opening at the upper end, where at least a pair of regions on the inner surfaces of the side walls that face to each other and correspond to the lower end to the middle toward the upper end, and the inner surface of the bottom wall are composed of the polymer chains. Preferred Method: The step (1) involves disposing the cathode in a position inside the cell by inserting it from the opening and disposing the anode in a position outside the cell, which faces the cathode through at least a pair of portions of the side walls that face to each other and correspond to the lower end to the middle toward the upper end, and through the bottom wall. Preferred Components: The polymer chain is cross-linked by a cross-linking group comprising the functional group including the secondary or tertiary nitrogen. The functional group including oxygen comprises at least one group selected from a hydroxyl, ether, carbonyl, carboxyl, or ester. The polymer chain further comprises a functional group including the primary nitrogen. The main polymer of the cell is a cycloolefin polymer. The contact angle against water in the region composed of the polymer chain is less than or equal to 85 degrees . EXAMPLE - No suitable example given.