Cathodic stripping voltammetric determination at a hanging mercury drop electrode of the environmental heavy metal precipitant trimercapto-s-triazine (TMT).
Trimercapto-s-triazine (TMT) is available commercially for precipitating heavy metals in effluents prior to discharge and for recovering silver and copper. The TMT content of an effluent for discharge is normally monitored down to about 2 ppm by means of its UV absorption at 285 nm. Indirect cathodic-stripping voltammetric methods of determining TMT at sub-ppb levels in standard solutions are reported here. These methods might prove suitable for the determination of TMT in effluent at levels lower than is currently possible. TMT can be accumulated and determined indirectly at pH 9.0 as its mercury salt down to sub-ppb levels. Accumulation is made at 0 V and the mercury TMT reduction peak is at -0.47 V. Alternatively, by adding nickel(II), TMT can be determined optimally at pH 7.8, using the catalytic nickel peak at -0.73 V and accumulating between -0.10 and -0.60 V: at this pH the HgTMT peak at -0.47 V is small. At slightly higher pH (pH 8.6) the nickel TMT complex can be accumulated directly at -0.40 V, but at this pH, however, a slightly increased sensitivity can be achieved by accumulating TMT as its mercury salt, at -0.1 V in the presence of nickel(II), the nickel TMT complex being formed during the potential sweep on the release of the TMT when the mercury salt is reduced. Unlike many other thiols TMT is not accumulated as its copper(I) salt on addition of copper(II) to the solution.
Electrochemistry of Mercury
The sections in this article are 
 
 
Double-layer Properties of Hg/Water Interface 
Potential of Zero Charge 
Surface Charge Density and Capacitive Current 
Experimental and Theoretical Studies of the Hg/Water Interface 
 
 
Double-layer Properties of Hg/Nonaqueous Media Interface 
Adsorption and Electrode Reactions at Hg Surface 
Deposition and Underpotential Deposition of Hg on Various Electrodes 
Underpotential Deposition of Mercury on Gold Electrodes 
Film Electrodes and Related Hg Electrodes 
 
 
Adsorption and Electrode Reactions of Inorganic Ions and Coordination Compounds of Metal Ions 
Analytical Applications 
 
 
Adsorption and Electrode Reactions Involving Organic Compounds 
Organic Compounds Containing Sulfur, Selenium, and Tellurium 
Organic Nitrogen Compounds 
Indicators and Dyes 
Vitamins and Antibiotics 
Enzymes and Coenzymes 
Other Organic Compounds 
Analytical Aspects of Adsorption of Organic Compounds 
 
 
 
 
Ammonium and Quaternary-substituted Ammonium Amalgams
Fragment Rotational State Distributions From The Dissociation Of NeIBr: Experimental And Theoretical Results
The IBr fragment rotational state distributions that result when the NeIBr van der Waals molecule undergoes vibrational predissociation have been measured in a pump–probe laser‐induced fluorescence experiment. Independent of initial vibrational state and the number of quanta of vibrational energy lost from the I–Br coordinate, the rotational distributions extend over the full range of energetically accessible states. From the observation of energetic constraints on the rotational distribution, the dissociation energy (D0) is calculated to be 65.5±1.2 cm−1 for the A electronic state, v=16. For the X electronic state, v=0, D0=71.8±1.2 cm−1. Quantum mechanical bound state calculations carried out on a model A electronic state potential energy surface are in quantitative agreement with this result. The rotational distributions are broader than that predicted by either a Franck–Condon or classical impulsive model for the dissociation. The distributions are qualitatively in accord with classical trajectory calc...