清除结石，用优级纯硝酸冷消化处理后，分别采用电化学分析法和分光光度法测定离体牙氟和磷的含量并计算氟磷含量比（F／P）。
Fluorine ( F ) and phosphorus ( P ) were measured with electrochemical analysis and spectrophotometry ; the ratio of F to P ( F / P ) was calculated .
优级纯