Departamento de Quimica, Universidade Federal de São Carlos, Rod. Washington Luiz, km 235, CP 676 CEP 13560-970 São Carlos, SP, Brazil.
Talanta. 2004 Feb 27;62(3):469-75. doi: 10.1016/j.talanta.2003.08.016.
A monosegmented flow system was employed for the determination of low contents of phosphate in natural water. In this approach, sample and reagents are simultaneously injected to a PTFE reaction coil where the homogenization of the mixture occurs while the monosegment is pumped forwards the photometric detector. The proposed system was evaluated by determining phosphate ion, based on the reaction of association between molybdophosphate and malachite green. It was evaluated individually the best concentration of the reagent solution in relation to blank signal (absorbance of the blank) and the sensitivity of the method. A factorial design was proposed to explain the contribution of each component on the formation of the ion association complex, evaluating the individual contributions as well as the synergistic and antagonistic effects. With the established conditions, phosphorous is determined in the concentration range of 5.0-75mug P PO(4)(3-)l(-1) (r=0.9992), with a detection limit of 0.70mug P PO(4)(3-)l(-1) and a relative standard deviation of 2% (20mug P PO(4)(3-)l(-1), n=8). The proposed method has a sampling frequency of 72h(-1).
采用单段流系统测定天然水中的低含量磷酸盐。在这种方法中，样品和试剂同时注入聚四氟乙烯反应盘管中，在单段向前输送到光度检测器的同时，混合物均匀化。该系统通过基于钼酸盐和孔雀石绿之间的缔合反应来测定磷酸盐离子进行了评估。单独评估了试剂溶液与空白信号（空白吸光度）之间的最佳浓度以及方法的灵敏度。提出了一个析因设计来解释每个成分对形成离子缔合配合物的贡献，评估各个成分的贡献以及协同和拮抗效应。在建立的条件下，磷在 5.0-75μg P PO(4)(3-)l(-1)（r=0.9992）的浓度范围内进行测定，检测限为 0.70μg P PO(4)(3-)l(-1)，相对标准偏差为 2%（20μg P PO(4)(3-)l(-1)，n=8）。该方法的采样频率为 72h(-1)。
