Direct Introduction of Water Sample in Multisegmented Flow-Injection Analysis for Sulfide Determination

Allergic contact dermatitis caused by N,N‐diethyl‐p‐phenylenediamine used in water quality analysis

“…DPD is a para‐amino compound that has benzene ring with amine and diethylamine in para‐substitution, and it is soluble in water, but not volatile. DPD is used in the form of DPD sulfate for measuring free chlorine and combined chlorine in drinking water . This method is used in many countries.…”

A Single FIA System Coupled with Reduction and Distillation Processes for the Determination of Sulfate Ion by Spectrophotometry

“…It is important to stress that, in our previous work, 8 the sulfite determination was done using a similar system, thus based on sensibility (0.2218 and 0.0783 for sulfide and sulfate determinations, respectively) and the stoichiometry ratio reactions (3:1). It can be inferred that the sulfate to sulfite conversion is about 94%.…”

“…6,7 In this work a FIA system used for the reduction, distillation and determination of sulfate (all in only one FIA system) was proposed. The method is based on our previous work, 8 in which sulfide was determined. The FIA system has a mini-reactor to which hydroiodic is added for the reduction of sulfate to sulfide.…”

“…9 The two main advantages of the proposed system are: i) rapidity in determining, because the samples are only filtered and introduced in the system with no more additional treatment; ii) improvement in the sensibility, because the available spectrophotometric methods for sulfate determination have a detection limit in the range of mg L -1 ; on the other hand, in sulfide (or sulfate reduced) detection, a limit of up to μg L -1 can be reached. 8 The idea to reduce sulfate to sulfide for subsequent determination of the latter is an old one, 10,11 nevertheless, up to now each step has been performed separately, making the method slow and showing poor accuracy. In the present work, the FIA system provided: speed, better precision and accuracy, lower cost, and less susceptibility to sample contamination.…”

Monosegmented Flow Analysis Exploiting Aqueous Two-phase Systems for the Determination of Cobalt

“…Flow analysis systems with solvent extraction (FA-SE) are very suitable for this purpose because they reduce the sample manipulation, time of analysis, the volume of waste and interference with the process from analysts. 6,7 Futhermore, flow systems can be easily automated. Flow monosegmented analysis techniques impart additional advantages, such as efficient clean-up of the system and high sensitivity (due the reduction in the dispersion of the analyte).…”