Lead diethyldithiocarbamate

Another aspect of tin as a constituent of electrode material is shown by tin(IV)TPP complexes incorporated into PVC membrane electrodes. These increase the selectivity to salicylate over anions such as Cl-, Br- I-, I()4, Cl()4, citrate, lactate and acetate. The specificity is attributed to the oxophilic character of the Sn ion in TPP at the axial coordination sites. Indeed, carboxyl groups incorporated into the membrane polymer compete for these binding sites. The complete complex structure is important. Substitution of TPP with octaethylporphirine results in loss of salicylate selectivity231. Preparation and analytical evaluation of a lead-selective membrane electrode, containing lead diethyldithiocarbamate chelate, has also been described232. 

Lead diethyldithiocarbamate [17549-30-3] M 503.7. Wash with H2O and dry at 60-70°, or dissolve in the min vol of CHCI3 and add the same vol of EtOH. Collect the solid that separates and dry as before. Alternatively, recryst by slow evaporation of a CHCI3 soln at 70-80°. Filter the crystals, wash with H2O until all Pb++ ions are eluted (check by adding chromate) and then dry at 60-70° for at least lOh. [A 49 1146 1977]. 

The reaction of aryl tellurium trichlorides and lead diethyldithiocarbamate in dry benzene produced aryl tellurium tris[diethyldithiocarbamates]2,6. 

Lead diethyldithiocarbamate dissolved in chloroform has been introduced as an effective reagent for concentrating copper (Hg, Au) from sea water. The metal ions are completely and selectively extracted from 500 ml of sea water into 10 ml of extractant solution. Lead diethyldithiocarbamate in chloroform should be added in at least 100-fold excess to the quantity of extractable metals. The sea water is favourably adjusted to pH 2-3 M). 

A solution of lead diethyldithiocarbamate in chloroform was found to be suitable for the extraction of gold from sea water. The method has previously been outlined in chapter 2.3.9 for the separation of copper84). Moreover, gold is accumulated from sea water by p-dimethylaminobenzylidenerhodanine on silica gel as described in chapter 2.3.12 92),... 

By taking advantage of the different stabilities of individual metal dithiocarbamates, it is possible to use ehloroform solutions of the relatively less-stable metal dithiocarbamates for the extraction of the metals which give more stable complexes [103-105]. In determining copper, for example, the colourless chloroform solution of lead diethyldithiocarbamate, Pb(DDTC)2, is used as the reagent. In this way the selectivity of metal reactions with dithiocarbamates may be enhanced. 

The interference of metals such as Fe, Mn, and Zn in the determination of copper has been overcome by using lead diethyldithiocarbamate instead of Na-DDTC. When a chloroform solution of Pb(DDTC)2 is shaken with an aqueous solution containing copper, a displacement reaction occurs ... 

Rather than adding masking agents or controlling the pH, the lead can be isolated beforehand by extracting lead iodide (ion association complex) or lead diethyldithiocarbamate. The lead iodide can be extracted with methylisobutyl ketone from HCl-acidified solution in the presence of KI (W2) while the diethyldithiocarbamate chelate can be extracted into carbon tetrachloride at pH 7 (L3). The lead can be back-extracted in the former case into an aqueous solution of sodium hydroxide and in the latter case into a solution of pH less than 7. Then it can be analyzed with dithizone. In this way, Zn, Cd, Hg, Ag, Al, and Sn do not interfere. 

Cation liquid ion-exchanger sensors are much more varied in type (99). Some examples are dialkyl- and di(alkylphenyl) phosphates for calcium and divalent ions (as discussed above) tetraphenylborates for onium ions and for drug type cations either by directly or by potentiometric titration lead diethyldithiocarbamate in trichloroethane for lead(II) (100) and mercury(II) PAN chelate in trichloromethane for mercury (101). 

A solution of lead diethyldithiocarbamate in chloroform reacts with copper salts in acid solution forming the red copper diethyldithiocarbamate which is also soluble in chloroform. This reagent is highly specific for Cu. 

Procedure. To a drop of the acidic test solution in a micro test tube, some drops of a 0.1% solution of lead diethyldithiocarbamate are added. After shaking, the organic layer becomes red to yellow when copper is present. 

Heterometric micro-determination of lead diethyldithiocarbamate derivative Spec A = 520 nm of 4-(2-pyridylazo)-resorcinol lead (1 1) complex in an ammonia-ammonium chloride medium at pH = 10 after extracting the lead in isobutyl methyl ketone... 

Water (alkyl lead) Complexation of sample with diethyldithiocarbamate extraction with pentane removal of water butylation extraction with nonane GC/AAS 1.25 ng/L 90-108 Chakra borti et al. 1984... 

Several ions (e.g., manganese, iron (II), iron (III), cobalt, nickel, copper, zinc, cadmium, lead, and uranyl) react with pyrocatechol violet, and to some extent are extracted together with aluminium. The interferences from these ions and other metal ions generally present in seawater could be eliminated by extraction with diethyldithiocarbamate as masking agent. With this agent most of the metal ions except aluminium were extracted into chloroform, and other metal ions did not react in the amounts commonly found in seawater. Levels of aluminium between 6 and 6.3 pg/1 were found in Pacific Ocean and Japan Sea samples by this method. 

Traces of copper and lead are separated [301] from macro amounts of calcium, magnesium, sodium, and potassium by adsorption from the sample onto active carbon modified with hydroxyquinoline dithizone or diethyldithiocarbamate. 

Chakraborti et al. [665] determined cadmium, cobalt, copper, iron, nickel, and lead in seawater by chelation with diethyldithiocarbamate from a 500 ml sample, extraction into carbon tetrachloride, evaporation to dryness, and redissolution in nitric acid prior to determination by electrothermal atomic absorption spectrometry in amounts ranging from 10 pg (cadmium) to 250 pg (nickel). 

Berman u°) could determine as little as 0.005 ppm cadmium in serum and 0.002 ppm in urine by extracting the cadmium from the digest with lead in sodium diethyldithiocarbamate into MIBK. Torres 112) isolated cadmium from urine by ion exchange chromatography. 

Edward Iratami [273] applied high performance liquid chromatography to the determination in river water of mercury(II), copper(II), nickel(II), cobalt(II) and lead(II) as their dithizonates and their diethyldithiocarbamates. The metals were first complexed, then the complexes... 

Liquid chromatography-absorption spectrophotometry was used by Vlacil and Hamplova [281] for the determination of lead and copper in natural waters. The metal diethyldithiocarbamates are extracted and concentrated by evaporation, followed by reversed phase liquid chromatography of the chelates. The copper and lead chelates can also be sequentially detected by spectrophotometry at 440 and 280nm. The detection limits for copper and lead were 8.6 and 17pg L 1 respectively, when liquid chromatography was used, and were 58 and 17pg L respectively when spectrophotometry was used. 

Poly(a-chloroacrylonitrile) decomposes to low molecular weight compounds when treated with nucleophiles [A,iV-diethyldithiocarbamate (Et2NCS2 ), PhS and azide ions]. An2 SRN mechanism was suggested for this reaction, in which an ET to the polymer leads to a radical and chloride ion. Coupling with the nucleophile and decomposition are the main reactions proposed for the radical intermediates98. The reaction of 2-chloro-2-methylpropionitrile, as a model compound, with TV, A-diethyldithiocarbamate (52% yield) and PhS (61% yield) was studied98. 

Metathetical reactions between aryl tellurium trichlorides and lead(ll) diethyldithiocarb-amates in dry benzene yielded aryl tellurium tris[diethyldithiocarbamates]4. 

This method is for the determination of cadmium, cobalt, copper, iron, manganese, nickel, lead and zinc, which are solvent extracted and concentrated as their diethyldithiocarbamate chelates. After destruction of the organic complexes dissolution of the residue in dilute acid gives a solution suitable for atomic absorption analysis [13]. 

---