Acid cacodylic 191 -, methods

For many years, arsenic has been regarded as an important environmental pollutant. It can enter the environment in many ways, for example use as an agrochemical, in smelting operations, and from coal fired power plants. Buchet and Lauwerys [70] list the relative toxicities for several arsenic compounds of high concern. In descending order they give arsine > arsenite > arsenate > methanearsonic acid (MMA) > dimethylarsinic acid (cacodylic acid, DMA). Methods which can accurately assess environmental and occupational exposure to these toxic arsenic compounds are necessary. 

Cabannes factor analy chem An equational factor to correct for the depolarization effect of the horizontal components of scattered light during the determination of molecular weight by optical methods. ko banz. fak-tor cacodyl orgchem (CH3)2As A radical found in, for example, cacodylic acid, (CH3)2A-sOOH. kak-3 dil ... 

Bait Trees and Trap Out. In these treatments, behavioral chemicals (i.e. aggregation pheromones) are combined with a direct control method to produce beetle mortality. Baited trees have been evaluated using frontalure in a trap-tree application with the herbicide cacodylic acid (9, 10). This treatment was only partially effective. However, this technique does not affect the adult natural enemy population, but rather the FI generation of the natural enemy population which is killed. 

Dimethyliodoarsine has been prepared by the distillation of cacodyl oxide with concentrated hydriodic acid,1 by the interaction of cacodyl and methyl iodide,2 and by distillation of the periodide, (CH3)4AsIT2.3 Dimethyliodoarsine, among other products, results from the interaction of methyl iodide and powdered arsenic3 and may be obtained by the reaction between potassium iodide and dimethyl-chloroarsine.4 5 When a solution of caeodylic acid, (CH3)2-AsO(OH), and potassium iodide is treated with hydrochloric acid and sulfur dioxide, dimethyliodoarsine settles out as an oil and may be recovered in 90% yield.6,7 The following directions are taken from an improvement of the last method and do not require the isolation of the cacodylic acid.6,8... 

Methods of Speciation and Fractionation. It is apparent that in order to understand the mobility of arsenic and its availability for reactions, methods of speciation and fractionation must be applied to sediment samples in field and laboratory studies. In this paper speciation refers to the separation and quantitative determination of inorganic arsenic, methanearsonic acid, and cacodylic acid. Compartmentalization involves identifying the major compartments for arsenic in a heterogeneous system (e.g. aqueous, adsorbed, occluded,...) and determining the amounts of arsenic in each compartment. Fractionation involves the extraction of arsenic from operationally defined fractions of the solid phase of an aquatic system (e.g. sediment). 

The hydrolysis of inorganic pyrophosphate has been carried out in cacodylate buffer, pH 5.5 [179], trichloroacetic acid was then added to terminate the reaction, denatured protein was sedimented by centrifugation, and suitable aliquots of the supernatant solution were assayed for inorganic phosphate by the method of Fiske and SubbaRow [163]. 

It can also be prepared by Cadet s cacodyl reaction. In this method, cacodyl oxide first is prepared by the reaction of K- or Na-acetate with arsenic trioxide, and this is then oxidised with HgO or air to dimethylarsinic acid (Treffler, 1944). 

The First Study. Forest-applicator exposure to MSMA and cacofirst studied by Tarrant and Allard (9). They collected individual urine samples on Monday mornings ari7 Friday afternoons for 9 consecutive weeks from five applicators (each using a different combination of application method and chemical) and one control. Workers were supplied with clean clothes daily, including two pair of cotton gloves (to be changed at noon, or earlier if one pair became substantially contaminated with herbicide). Complete data were obtained for weeks 2, 3, 4, 7, and 8 (except for the injection hatchet-cacodylic acid combination, which was not included in the analysis). 

Table II. Mean Concentration of Arsenic in Urine from Forest Workers Applying MSMA or Cacodylic Acid via the Hack and Squirt Method in Operational Precommercial Tree Thinning (11)...

Seven operational application units were monitored on the basis of information from the previous tests in an effort to minimize applicator exposure (11). Operational monitoring involved six individual application crews of from five to ten applicators one crew treated two units. All crews used the hack and squirt method, but some applied cacodylic acid and others MSMA. The time required to complete a unit varied from 1 to 3 months, but not all crews were involved with chemical thinning each day. 

Later analyses showed that the substance had this formula, and Bunsen adopted the proposal of Berzelius that it should be named Kakodyloxyd (cacodyl oxide), from KaKa>8rj9y stinking, and regarded as the oxide of a radical cacodyl C4Hi2As2 = Kd (Berzelius, with reasons, used Kk). By the action of concentrated acids on cacodyl oxide, Bunsen prepared the chloride, iodide, and fluoride of cacodyl, and the cyanide, diese schone aber beispiellos giftige Verbindung by the same method, but more conveniently by distilling cacodyl oxide and mercuric cyanide. He also prepared cacodyl sulphide and selenide. 

---