Lindane detection limit

Renberg [64] recommends the use of y-BHC (lindane), DDE or DDT as a gas chromatographic internal standard. The relative retention times of the derivatives corresponding to these internal standards are shown in Table 15.3. The detection limits for the different substances for 1L of a water sample are 0.0001-0. lppb. 

Before the introduction of gas chromatography, the detection of toxaphene was carried out mainly by infrared spectroscopy [57, 58], measurement of total chloride content [59], or colorimetric methods [60]. Colorimetric methods had a detection limit around 100 pg/mL [60]. Coulson et al. pubhshed the first gas chromatogram of toxaphene in 1959 which clearly demonstrates the problem of the analysis of toxaphene. Due to the high number of components no signals of single compounds were observable in contrast to the case for other chloro-pesticides such as DDT, lindane, and chlordane [61]. 

The latest production model of the microcoulometric detection system has a minimum detectable limit of about 1 ng of chlorine but, in the writer s opinion, the minimum for practical use is about 3 ng. This estimate is based upon responses obtained by Dohrmann Instruments personnel with standard solutions of pure lindane. These results were obtained in mode I operation (gas flow into the cell between the electrodes) rather than mode II operation (gas flow impinging directly on the sensor electrode), a more sensitive mode currently being used on last year s model detector in our laboratories. Mode I is preferred, for operating parameters are much less critical. 

The electron capture detector is an essential comp>onent in the determination of trace amounts of organochlorines for which its sensitivity is roughly five orders of magnitude higher than for hydrocarbons. For instance, the detection limit for lindane may be as low as... 

The cholinesterase electrode was constructed on this basis for the total determination of organophosphates and carbamates [32]. This electrode is also sensitive to other toxic compounds with very low detection limits (paraquat (3 ppm) trichlorophenol (20 ppm) methylazinphos (150 ppb) lindane (15 ppm) and mercury (4 ppm)) [135]. This type of biosensor uses enzymatic inhibition and can be incorporated in an automated system for the quality control of water, and, notably, waste water [291]. 

The US EPA set a drinking water limit of 0.2 parts per billion (ppb) of lindane. Industrial dumping sites such as the one in Allegheny County, Pennsylvania contain an estimated 400 tons of lindane waste and other waste dumped over a 50-year period on 30 acres of land. The runoffs from this site as well as others have the potential to contaminate drinking water with lindane. Lindane is regularly detected in surface water in the United States (see US Geological Survey monitoring studies). 

Lindane Application of gas chromatography-mass spectrometry. Limit of detection 0.1 xg/kg [170]... 

A seven year study by the Indian Council of Medical Research released in 1993 analysed 2205 cow and buffalo milk samples from 12 states. HCH (lindane) was detected in about 85% of the samples, with up to 41% of the samples exceeding tolerance limits. DDT residues were detected in 82% of the samples and 37% contained residues above the limit of 0.05 mg/kg, in some cases 44 times higher at 2.2 mg/kg. 

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