【摘要】 <正> 氟进入人体的途径大致有三:空气、饮水和食物。广州市区空气氟浓度为0.002～0.009毫克/立方米,没有超过国家标准(0.02毫克/立方米)。饮水氟的高低是不难测定的。自来水加氟的标准,世界卫生组织定为1ppm(百万分率,即毫克/公斤或毫克/升),广州自来水加氟则控制在0.6～0.8ppm。有些人主张广州自来水不用加氟,这可能是观点不同,不是水氟分析结果的问题。在分析结果上出现了分歧的是食物氟,因为同一地区的食物,这一单位测出食物氟偏高,另一单位测出食物氟偏低,从而对自来水加氟作出不同的结论。更多还原

【Abstract】 An acid extraction-fluoride electrode method was used to determine fluoride in food. The method consists of 3 steps: (1 ) weigh out 1.00 gram of the sample, powder, extraction with 25.0 ml of 0. lNHCI)stirring for 1 hour, ( 2 ) addition an equal volume of TISAB ( pH = 5.5 ) and 2.5 ng of background fluoride, and ( 3 ) measurement of fluoride activity with an ion selective electrode by standard addition technique.The results of analysis of fluoride in foods samples are presented in tabular form ( table 1 ) . It is shown that the fluoride content of foods sold in Guangzhou give the following mean values and standard deviations ( ppm F, dry weight) : ( 1 ) grain crops: rice, 0.44 ± 0.15 ( 22 ) , flour, 0.39 ±0.14 ( 13 ); ( 2 ) vegetables:range 0.21~6.75, median value 3.50; ( 3 ) fruits and juices: range 0.10~2.16, median value 1.13; (4)meats: about 1 ppm, fish: range 3.0~16.7, median value 6.85, eggs: range 0.32~ 0.55.and ( 5 ) non-staple food and flavouring: range 0.1~3.0 (except the teas ) .In order to check the reliability of the above results, some samples of low content ( <lppm ) of flouride were determined parallelly by ashing-fluoride electrode metiod, and sent to other laboratory (Institute of Test A-nalysis, Guangdong). In the significance test, mean value between laboratories was found statistically not significant difference ( P>0.01, table 2) .According to the fluoride content of foods, water supply, and air in Guangzhou, the estimated daily fluoride intake is about 1.47mg for children and 2.30mg for adults approximately(table 3 ) .更多还原