Экология/6. Экологический мониторинг

Sailaukhanuly Ye., Kenessov B.N., Kamysbayev D.H.

Center of Physicochemical Methods of Research and Analysis,

Al-Farabi Kazakh National University

Determination of DDT in water using solid phase microextraction coupled with gas chromatography mass spectrometric detection

Dichlorodiphenyltrichloroethane (DDT) is a known insecticide, which was first synthesized in 1874, insecticidal properties of DDT were found during the Second World War. By the middle of 1980s in the world produced about 3.5 million tons DDT [1].

DDT has mutagenic and carcinogenic properties, is a poison the central nervous system. Causes pathological changes in the liver and kidneys of animals. It has a cumulative effect. Retained in the bodies of up to 20 days [2]. Of particular concern raised when DDT was detected in breast milk. The ability of DDT to accumulate in human adipose tissue and produce high residual toxicity was the cause of termination of production of DDT in the 70-80s by the highly developed countries [3].

DDT is very persistent in the environment, the half-life ranges from 2 to 25 years. In the environment, DDT can break through the biotic and abiotic ways. DDT in soil can also be deployed. Movement of pesticides in soil can occur by leaching, runoff and volatilization. Over very long periods of time DDT may be able to eventually leach into groundwater, especially through soils with little soil organic matter [4].

The method of solid phase microextraction is clean and rapid method compare to other methods using a large quantity of organic solvents [5].

The fiber 100 μm polydimethylsiloxane (PDMS) was selected for determination DDT, as DDT has a high octanol-water and slightly soluble in water [5]. This PDMS fiber is the most optimal for the direct extraction of DDT from aqueous samples. DDT was extracted with direct input fibers in water 60 minutes with constant stirring. GC–MS analyses were carried out using an Agilent 6890/5973 N (Agilent, Santa Clara, USA).

We obtain the calibration dependence of the peak area of DDT concentrations in the concentration range of 10-1000 ng/L methods SPME/GC/MS (Figure 1). Dependence described by the following equation:

S = 0.0616 x C_DDT

Where, S - area of the peak of DDT, × 10^-3 and C_DDT - the concentration of DDT ng/L.

Figure 1 - The calibration dependence of the peak area of DDT concentrations in water

Approximation coefficient (R²) was 0.996. So, during experiments, the optimal parameters determinations of DDT were optimized by SPME/GC/MS. The method has been successfully tested water samples contaminated with DDT.

References:

1. V.A.Isidorov. Introduction to chemical ecotoxicology. - St. Petersburg. - HimIzdat. - 1999. – 140 p.

2. M.D.Shvaiko. Toxicological Chemistry. - Moscow. - "Medicine". -1975. 376 p.

3. G.Fellenberg. Pollution of the environment. Introduction to environmental chemistry. - Moscow. - Mir. - 1997. – 232 p.

4. Sh.U.Kahn, Fundamental Aspects of Pollution Control and Environmental Science 5. Pesticides in the soil environment. Elsevier scientific publishing company, New York, 1980, 240 p.

5. J.B.Pawlyszin, S.Magdic, Analysis of Organochlorine pesticides using solid-phase microextraction. Journal of chromatography A, 723 (1996), p.111-122.