二甲酚橙光度法测定铌(本刊1978年第4期),钼有干扰。在测定高铌(含量>0.2%)试样时,影响还不显著,但测定低铌(含量<0.15%),而钼含量>0.5%的试样时,影响就比较显著。含钼1%,使铌的结果偏高约0.005%,2～4%钼偏高0.008～0.013%.钼的干扰随铌含量而略有不同,铌量低或不含铌时,影响大些;再者,钼显色的再现性较差,进行校正有一定的误差。为了排除钼的干扰,可以在原操作方法中增加一分离步骤,即在低铌的测定方法中,在加入1:50氢氟酸2毫升,煮沸约1分钟,使过氧化氢分解,冷却后,加入安息香肟的乙醇溶液(2%)1.0毫升(含钼2～4%)或0.5毫升(含钼～2%)使钼沉淀[在酸性溶液中,安息香肟定量沉淀钼,部分沉淀铌、钽、钨、铬 Xylenol orange spectrophotometric determination of niobium (No. 4, 1978), molybdenum interference. In the determination of high niobium (content> 0.2%) of the sample, the impact is not significant, but the determination of low niobium (content <0.15%), and molybdenum content of> 0.5% of the sample, the impact is more significant. Molybdenum 1%, so that the results of niobium high about 0.005%, 2 ~ 4% molybdenum high 0.008 ~ 0.013% .Molybdenum interference with the niobium content slightly different, niobium content is low or not, the impact of larger In addition, the reproducibility of molybdenum color is poor, there is a certain error correction. In order to eliminate the interference of molybdenum, a separation step can be added to the original operation method, that is, in the method for measuring low niobium, 2 ml of 1: 50 hydrofluoric acid is added, boiled for about 1 minute, hydrogen peroxide is decomposed, and after cooling, 1.0 ml (2 to 4% molybdenum) or 0.5 ml (molybdenum to 2%) of molybdenum is added to precipitate molybdenum with an added solution of benzoinoxime (2%) [In an acidic solution, , Tungsten, chromium