DDT, detection

Pump immediately after the EDC-NHS solution, a previously prepared lx Fsolution of the bioreceptor in the immobilization buffer see Note 13) at 0.15 pL/s. Concentration must be optimized for each application however, it typically ranges from 10 to 50pg/mL. For DDT detection, lx Fof6pg/mL in PBS pH 7 should be used. The bioreceptor immobilization produce a new deflection, very similar to the one showed in Fig. 5A. 

Prepare series of solutions (minimum 4-5) of different concentrations of the antibody in triplicate. For DDT detection, concentrations ranging from 0.5 to 10 pg/mL were used. 

In this core, concentrations of PCBs (determined as Aroclor 1254 and 1260, by high resolution gas chromatography, electron capture detection and high resolution gas chromatography-low resolution mass spectrometry) were <30 ng and those of total DDT (p,p DDT + p,p DDD + p,p DDE) <5 ng g Campesan et al. (21) in 11 sediment samples from Valle di Brenta, determined by GC-ECD the following mean concentrations (ng gd.w.) ... 

When DDT was widely used, it was released into the environment in a number of different ways. The spraying of crops, and the spraying of water surfaces and land to control insect vectors of diseases, were major sources of environmental contamination. Waterways were sometimes contaminated with effluents from factories where DDT was used. Sheep-dips containing DDT were discharged into water courses. Thus, it is not surprising that DDT residues became so widespread in the years after the war. It should also be remembered that, because of their stability, DDT residues can be circulated by air masses and ocean currents to reach remote parts of the globe. Very low levels have been detected even in Antarctic snow ... 

Co(TPP) has been demonstrated to act as a catalyst for the electrocarboxylation of benzyl chloride and butyl bromide with CO - to give PhCHiCfOiOCH Ph and Bu0C(0)C(0)0Bu, respectively. The propo.sed mechanism involved Co(TPP)R and [Co(TPP-N-R) as intermediates (the latter detected by spectroscopy) in the catalytic production of free R or R-, which then reacted directly with Co(TPP) precipitated on graphite foil has been successfully used for the determination of organic halides, including DDT and 1,2,3,4,5,6-hexachlorocyclohexane (lindane), to sub-ppm level in aqueous solution. Deoxygenation of the solutions is not required, and the technique is moderately insensitive to the ionic composition of the solution. ... 

Unlike DDT, TDE does not lose one mole of hydrogen chloride when heated with ferric chloride, but rearranges to form an isomeric compound (31). It may be possible to develop this observation into an analytical method to differentiate between the two products or to detect the one in the presence of the other. 

Riemschneider (96) purposely swallowed both DDT and DFDT, and reports that no essential pharmacological differences could be detected in the two compounds. 

In 1976-78, OCPs were detected without exception in every body of water studied in the Caucasus region (lake Sevan, the Mingechaursk Reservoir, and the Razdan, Inguri, Kura, and Rioni Rivers). DDT was found in 77.3% of samples, HCH in 96.4% and granosan in 100%. 

Pesticides contaminate not only surface water, but also ground water and aquifers. By 1990 in the USSR, 15% of all pesticides used were detected in underground water [29]. Pesticides were detected in 86% of samples of underground water in Ukraine in 1986-87 (including DDT and its metabolites, HCH, dimethoate, phosalone, methyl parathion, malathion, trichlorfon, simazin, atrazine, and prometrin). In actual fact, the number of pesticides was apparently larger, but the laboratory was able to determine the content of only 30 of the 200 pesticides used at that time in Ukraine [29]. In the 1960s, in the Tashkent and Andizhan oblasts of Uzbekistan, the methylmercaptophos content in the water of studied well shafts was, by clearly underestimated data, 0.03 mg/l (MPC was 0.01 mg/l), of DDT was 0.6 mg/l (MPC was 0.1 mg/ I), and of HCH was 0.41 mg/l (MPC was 0.02 mg/l) [A49]. 

Research on pesticides in food products carried out in 1965-66 in Khersonsk Oblast (Ukraine) detected HCH in 80% of vegetable product samples, and DDT in 74.3%o (in products of animal origin, these figures were 10%o and 93.8%), respectively). The daily diet of subjects from Group I intensity work contained 2.31 mg of DDT [A77]. 

In Table 3.16, shaded pesticides are those detected in products where they should have been absent, because 1) they were banned (DDT, heptachlor) 2) their presence in all food products was banned (methyl parathion, 2,4-D, etc.) 3) they were not permitted to be present in particular food products (trichlorfon in meat and dairy products) and 4) they were not permitted to be used with particular crops. Unfortunately, practically the entire table is shaded, which shows that all regulations were violated. 

Graham A., Carlson C., Edmiston P., Development and characterization of molecularly imprinted sol-gel materials for the selective detection of DDT, Anal. Chem. 2002 74 458-467. 

Despite the restrictions to usage and production there still remain extensive amounts of DDT and its metabolites in the environment. Traces of DDT were detected all around the world, including regions where there are no direct sources, such as open ocean waters [Tanabe and Tatsukawa (1983),Iwata et al (1993)], the Arctic [Patton et al (1989)], and high mountain areas [Villa et al (2003)]. 

To evaluate the potential risk of Ebro river sediments, the concentrations detected were compared to actual legislation. The WFD does not specifically address sediment management [95]. In contrast to this, the Canadian sediment quality guidelines for the protection of aquatic life [96] provide data for different types of sediments and include 33 compounds, PAHs and DDTs among them. All the PAHs included in the Canadian guidelines are present above the limit, ranging from 3% of the samples for naphthalene to 90% for dibenzo(a,h)anthracene. Special attention has to be paid to benzo(a)pyrene and dibenzo(a,h)anthracene, considered... 

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