应用吸光光度法测定液体有机产品的色度

DETERMINATION OF COLOURITY OF ORGANIC LIQUIDS BY ABSORPTIOPHOTOMETRY

根据色度学原理应用吸光光度法测定了工业乙酸酐及冰乙酸产品的色度。应用分光光度计 ,建立标准曲线 ,通过测定样品在 3 80 780nm处的透光度 ,计算黄变度 ,查得其相应铂 钴色度号。此方法能准确地反映出样品的真实颜色 ,消除了人为误差 ,提高了分析方法的准确度。适用于日常工业分析、科学研究及仲裁 ,对于目视比色时存在色调干扰的样品测定尤为重要。

Based on the fundamentals of colorimetry, the colourity of industrial acetic anhydride and glacial acetic acid was determined by using spectrophotometer. Transmittances of the sample in the spectrum range between 380~780nm are measured at intervals of 10nm. The tristimulus values ( x, y and z ) can be calculated from the transmittance values. Since the tristimulus values are used to express the degree of additivity of the three primary colours (red, green and blue) the colourity of substances can be quantitatively illustrated. The index of degree of yellow change, Yi, is calculated from the tristimulus values. A standard curve between 16 standard color codes (prepared with Pt Co standard solutions) and the degree of yellow change (Δ Y ) is prepared. The color code of the sample can be found from this standard curve. The standard deviations of three acetic anhydride samples and three glacial acetic acid samples at different colourity levels ( n =5) are calculated giving the following values: 0.14, 0.11, 0.26 for acetic anhydride; 0.14, 0.21, 0.21 for glacial acetic acid. The proposed method is established on a more reasonable and quantitative basis, and errors due to differences in color hue usually happened in visual method are eliminated, hence more accurate and precise results can be obtained. This method can be used in routine quality inspection, and is also suitable to be used in research works and referee determination.