Diphenyl ether analysis

CoMSIA (comparative molecular similarity index analysis) is a recent development from CoMFA and does not suffer from the alignment problem. It has been used to model hERG potassium channel inhibition by drugs [59] and the toxicity of phenylsulfonyl carboxylates [60], organophosphates [61], and polybrominated diphenyl ethers [62], with results comparable to those from CoMFA. 

To determine the diphenyl ether herbicides in the samples, GC/ECD or GC/NPD is used in general. GC/ECD is preferred to GC/NPD owing to its higher sensitivity. An aliquot of GC-ready sample solution is injected into the gas chromatograph under the conditions specified below. In addition, multi- and confirmatory analysis of residues is carried out using gas chromatography/mass spectrometry (GC/MS) in the selected-ion monitoring (SIM) mode. 

Multiresidue analysis of 72 pesticides including three diphenyl ethers was carried out by GC/NPD under the following conditions column, 5% DB-5 (30 m x 0.53-mm i.d., 0.53- xm film thickness) temperature, column 100°C(1 min) increased at 5 °Cmin to 280°C (lOmin), inlet and detector 280°C gas flow rates. He 11.2mLmin H2 3.5mLmin air llOuiLmin" injection volume, 2 rL. The retention times... 

Okumura et al reported State regulatory programs for pesticide residues in food crops analyzed by the CDFA. In the multiresidue analysis of several organochlorine pesticides including diphenyl ether herbicides, bifenox, nitrofen and oxyfluorfen, HPLC has also been used. 

Quantitative analysis is performed by the calibration technique. A new calibration curve with a standard solution of each diphenyl ether herbicides is constructed, plotting the peak area against the amount of standard solution injected. Each diphenyl ether herbicide in the sample is measured by using the peak area for each standard. Before each set of measurements, the GC and HPLC system is checked by injecting more than one standard solution containing ca 0.01-2 mg L of each compound. 

The MDCs are estimated from an S/N of the diphenyl ether peaks of at least of 3 in the recovery test. With fortification levels between 0.2 and 0.5mgkg recoveries of bifenox from brown rice matrices ranged from 85 to 102% with the limit of detection (LOD) and limit of quantitation (LOQ) being 0.010 mg kg according to the analytical method of the Notification of the Ministry of the Environment, Japan. By the residue analysis method described in Section 2.2.2(3), recoveries of chlornitrofen and CNP-NH2 from brown rice and vegetables with fortification levels of 0.04-0.10 mg kg ranged from 82 to 98%. The LOD for each sample was 0.005 mg kg for chlornitrofen and CNP-NH2. ... 

Diphenyl ether herbicides are generally extracted from 10 to 50 g of air-dried soil with an organic solvent such as acetone, methanol and benzene by sonication, mechanical shaking or Soxhlet extraction. If necessary, the extracts are then cleaned by column chromatography or SPE. The extract is evaporated completely to dryness and the residue is dissolved in an appropriate volume of the solvent for GC analysis. The reduced amine metabolites are extracted under alkaline conditions. 

Meironyte D, Bergman A, Noren K (1999) Analysis of polybrominated diphenyl ethers in Swedish human milk. A time-related trend study, 1972-1997. Organohalogen Compd 58(6) 329-341. doi 10.1080/009841099157197... 

All of the organohalogen compounds studied were commercial products obtained from various manufacturers and used as received. Only the DBDPO was purified further by recrystallization for some of the chromatography and thermal analysis experiments. Samples of antimony trioxide and antimony pentoxide were also obtained from commercial sources. The ultrapure antimony trioxide, bismuth trioxide, bismuth metal, antimony metal, dibenzofuran and diphenyl ether were all obtained from Aldrich Chemicals. The poly(propylene) (PP) resin was 0.7 mfi, food grade from Novamont and the poly(ethylene) was unstabilized, high molecular weight, HDPE from American Hoechst. 

Pijnenburg AMCM, Everts JW.de Boer J, Boon JP (1995) Polybrominated biphenyl and diphenyl ether flame retardants analysis, toxicity, and environmental occurrence. In Ware GW (ed) Reviews of environmental contamination and toxicology, vol 141. Springer, Berlin Heidelberg New York, p 2... 

Mill, J. S. (1844) On the Definition of political economy and on the method of investigation proper to it , in Collected Works, vol IV (1967), Toronto University Press, Toronto Meironyte, D., Noren, K. and Bergman, A. (1999) Analysis of polybrominated diphenyl ethers in Swedish human milk. A time related trend study, 1972—1997 , Journal of Toxicology and Environmental Health Part A, vol 58, no 6, pp329—341 O Riordan, T. and Cameron, J. (eds) (1994) Interpreting the Precautionary Principle, Earthscan, London... 

Polybrominated Diphenyl Ethers. Information on the relative importance of different routes of exposure to PBDEs is limited. Data on the concentrations of PBDEs in foods, collected using a market-basket approach, are needed to determine concentrations of PBDEs in foods consumed by the general population. Data on the PBDE concentrations in foods grown in contaminated areas, particularly in the vicinity of hazardous waste sites, are also needed. Data on congener-specific PBDE analysis of food, especially plant products, would be useful. More monitoring data on the concentrations of total PBDEs as well as conquers in air in remote, rural, urban, and areas near hazardous waste sites and incinerators are needed. Data on PBDE concentrations in finished drinking water nationwide would be helpful. 

The purpose of this chapter is to describe the analytical methods that are available for detecting, measuring, and/or monitoring polybrominated biphenyls and polybrominated diphenyls ethers, their metabolites, and other biomarkers of exposure and effect to polybrominated biphenyls and polybrominated diphenyls ethers. The intent is not to provide an exhaustive list of analytical methods. Rather, the intention is to identify well-established methods that are used as the standard methods of analysis. Many of the analytical methods used for environmental samples are the methods approved by federal agencies and organizations such as EPA and the National Institute for Occupational Safety and Health (NIOSH). Other methods presented in this chapter are those that are approved by groups such as the Association of Official Analytical Chemists (AOAC) and the American Public Health Association (APHA). Additionally, analytical methods are included that modify previously used methods to obtain lower detection limits and/or to improve accuracy and precision. 

ECD = electron capture detection GC = gas chromatography GPC = gel permeation chromatography HRMS = high resolution mass spectrometry LC = liquid chromatography MS = mass spectrometry NAA = neutron activation analysis NCI = negative chemical ionization PBDEs = polybrominated diphenyl ethers... 

Hori S, Akutsu K, Kitagawa M, et al. 2000. Development of analysis for polybrominated diphenyl ether in seafood and actual contamination of seafood. Organohalogen Compounds 47 214-217. 

Johnson A, Olson N. 2001. Analysis and occurence of polybrominated diphenyl ethers in Washington state freshwater fish. Arch Environ Contam Toxicol 41(3) 339-344. 

Sjodin A, Thuresson K, Hagmar L, et al. 1999b. Occupational exposure to polybrominated diphenyl ethers at dismantling of electrons. Ambient air and human serum analysis. Organohalogen Compounds 43 447-451. 

Wenning RJ. 2002. Uncertainties and data needs in risk assessment of three commercial polybrominated diphenyl ethers probabilistic exposure analysis and comparison with European commission results. Chemosphere 46(5) 779-796. 

The t3C resonances of xanthone (21) have been assigned on the basis of shift analysis of the structurally related compounds anthrone and xanthene (77P735) and by correlation with the component molecules diphenyl ether and benzophenone (78T1837). Delocalization of the non-bonding electron pairs at oxygen, leading to an increase in aromaticity of the pyranone ring, accounts for the deviation of the chemical shifts of C-4a, C-8a and the carbonyl carbon atom from the calculated values. 

Hites RA (2004) Polybrominated Diphenyl Ethers in the Environment and in People A Meta-Analysis of Concentrations. Environ Sci Technol 38 945... 

Hites, R.A., 2004. Polybrominated diphenyl ethers in the environment and in people A meta-analysis of concentrations. Environ. Sci. Technol. 38, 945-956. 

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