【摘要】 磷钼蓝(PMB)与十六烷基三甲基溴化铵(CTMAB)可生成疏水性的PMB-CTMAB离子缔合物,被Sep-PakC18小柱萃取富集,基于此建立了SEP-PAKC18小柱固相萃取-分光光度法测定海水中痕量活性磷酸盐的新方法。对洗脱液酸度、萃取流速、试剂用量、反应时间与温度等实验参数进行了优化选择,并考察了盐度对测定结果的影响。实验结果表明,PMB-CTMAB在SEP-PAKC18小柱上可被有效地定量萃取;盐度在25~45范围内,对测定结果没有影响。在优化的实验条件下,以盐度为35的人工海水作为基底,方法的线性范围为0.18~4.00μg/L;平均回收率为98.5%;检出限为0.05μg/L。对实际海水中痕量活性磷酸盐进行测定,相对标准偏差(RSD)为2.7%~5.6%。与广泛采用的MAGIC法比较,结果无显著差异。新方法具有消耗试样体积少、测定速度快等优点。更多还原

【Abstract】 An ion pair compound of phosphomolybdenum blue （PMB） with cetyltrimethylammonium bromide （CTMAB） can be extracted by solid phase extraction technique on C₁₈ column. Based on this, a novel method was established to determine trace orthophosphates in seawater. Experimental parameters, including acid （concentration） of the eluant, the extracting flow rate, the reagent concentrations, the reaction time and （temperature）, were optimized. The effect of salinity was also investigated. The results showed that PMB-（CTMAB） could be efficiently extracted, and the extraction was not influenced by the salinity within 25 and 45. Under the optimized conditions, using artificial seawater （35） as a matrix, the linearity, the recovery and the （detection） limit of the proposed method were found to be 0.18 to 4.0 μg/L , 98.5% and 0.05 μg/L , （respectively）. The RSDs ranged from 2.7% to 5.6% for the real seawater samples. Three seawater samples were analyzed with both the proposed method and magnesium hydroxide-induced coprecipitation （MAGIC） method, and the （results） showed no significant difference with t test. The proposed method had the advantages of being more sensitive, faster and sampler saving.更多还原