Single-sweep polarographic techniques useful in micropollution studies of ground and surface waters

Abstract

Single-sweep polarography offers many advantages to the chemist who is faced with the control and analysis of water quality today. Some of these such as a technique that can characterize soluble species; a highly sensitive (parts-perblllion) method suitable for fleld operation, automation, and continuous monltoring; and direct analyses, with preconcentration or separation of the micropollutant from the water sample many times unnecessary, and matrix problems of interference minimized, are discussed. Single-sweep polarographic procedures have been developed in these laboratories that have proved useful In detecting and analyzing for a number of micropollutants of river water, well and spring water, tap water, sea water, and effluent waters from many sources. Potential methods of analysis are discussed for chromium (Crl" and Cr"), arsenic (As111 and AsV) and iodine (I-and 103-) soluble ionic species. Some uranium, selenium, lead, cadmium, tellurium, thallium, manganese, copper, nickel, and zinc ionic species were also studied and techniques are presented for thelr analysis. Techniques for the single-sweep polarographic analysis of traces of explosives and plasticizers in water, such as nitroglycerine, 1,2-propylene glycol dlnitrate, 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitro-1,3-5-hexahydrotrlazlne (RDX), diethyl phthalate, and dibutyl sebacate are also presented and discussed.Single-sweep polarography ( 1 ) is a simple, rapid, and inexpensive method of trace element analysis that offers many advantages in the surveillance and control of micropollutants that may find their way into our ground and surface water supplies.It is the purpose of this research to present and describe some useful single-sweep polarographic techniques that have been developed and used in this laboratory (2, 3 ) for detecting and measuring directly extremely low levels of cationic and anionic species as well as some organic micropollutants in natural water. These techniques require little or no prior concentration of the pollutant and only a few milliters of sample is needed for the analysis. EXPERIMENTALIn general, ground water is purer than surface water due to the fact t h a t it is more remote both physically and in time from environmental pollution. Since the drinking and doniestic water supply of this Center (NWC) is obtained from fairly deep and uncontaminated wells (200 to 800 feet), it was decided to use this water as a standard to establish a norm or base line from which toxic micropollutants might be rapidly detected and measured if they entered the water supply. This water provided a large supply of a relatively low level metal soluble species and low level organic material supporting electrolyte for the polarographic studies. The well water used is very low in organic ligands which are potentially strong complexing agents and interfere seriously in some trace element analysis. This was determined by standard additions of both CuL+ and Zn2+ to the well water. The single-sweep polarograms for both Cu2+ and Zn2+ proved to be linea...

Analysis and Speciation of Traces of Arsenic in Environmental, Food and Industrial Samples by Voltammetry: a Review

“…On account of that, more often than not, reduction to As(III) prior to the accumulation/determination step must be performed, both for total element quantification and speciation studies, although techniques for direct As(V) analysis have also been successfully implemented. In general, for the latter case, pyrogallol [38,39], catechol [40] or mannitol [21,23,41] is used. Still, there are examples [7,22] of As(V) determination by ASVon a gold working electrode just in 0.1 mol L À1 HCl as supporting electrolyte, using deposition potentials of À 0.8 and À 1.6 V, respectively.…”

The voltammetric determination of trace U(VI) in seawater —adsorptive preconcentration of the 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol complex

“…Milner et al (4) used a pulsed polarographic method but a complex separation and preconcentration step was required. Whitnack (5) attempted a direct polarographic analysis but was unable to detect uranium in seawater. A sensitive "catalytic"…”