Analysis of persistent halogenated hydrocarbons in fish feeds containing fish oil and other alternative lipid sources

A trade-off exists between beneficial n-3 long-chain polyunsaturated acids and toxic persistent halogenated hydrocarbons (PHHs), both of which primarily originate from fish oil commonly used in fish feeds. Alternative lipid sources are being investigated for use in fish feeds to reduce harmful contaminant accumulation, hence, research is needed to evaluate PHHs in fish feeds with various lipid compositions. An analytical method was developed for PHHs including nine organochlorine insecticides (OCPs), 26 polychlorinated biphenyls (PCBs) and seven polybrominated diphenyl ethers (PBDEs) in fish feeds with differing proportions of fish oils and alternative lipid sources by GC-ECD after accelerated solvent extraction, gel permeation chromatography (GPC), and sulfuric acid cleanup. The GPC removed the majority of the neutral lipids and sulfuric acid treatment effectively destroyed the polar lipids. Thus, the combination of the two methods removed approximately 99.7% of the lipids in the extracts. The method detection limits were less than 5 ng/g dry weight (dw) for most PHHs, while recoveries were 75-118%, 67-105%, 69-92%, 63-100% and 94-144% with relative standard deviations of 0.2-39%, 0.3-20%, 0.5-12%, 1.5-18% and 1.5-15% for PHHs in five types of fish feeds made from different lipid sources. Although the source of lipid showed no impact on cleanup efficiency and the developed method worked well for all feeds, fish feeds with 100% fish oil contained background PHHs and more interference than feeds containing alternative lipids.     

The Preparation of 4,5-Dihydro-5-Phenyl-5-(2-Phenylethenyl)Isoxazoles, 4,5-Dihydro-5-Methyl-5-(2-Phenylethenyl)Isoxazoles,or 4,5-Dihydro-5,5-DI-(2-Phenylethenyl)Isoxazoles from Dilithiated C(α),O-Oximes and Select α,β–-Unsaturated Ketones

C(α),O-oximes were dilithiated with lithium diisopropylamide and condensed with three α,β-unsaturated ketones: (2E)-1,3-diphenyl-2-propen-1-one, or (1E, 4E)-1,5-diphenyl-1,4-pentadien-3-one, or (3E)-4-phenyl-3-buten-2-one, followed by immediate acid cyclization to variously substituted 4,5-dihydroisoxazoles: 4,5-dihydro-5-phenyl-5-(2-phenylethenyl)isoxazoles, 4,5-dihydro-5-methyl-5-(2-phenylethenyl)isoxazoles, or 4,5-dihydro-5,5-di-(2-phenylethenyl)-isoxazoles.     

A field-scale demonstration of a novel bioremediation process for MGP sites

The Institute of Gas Technology (IGT) has developed and demonstrated an integrated chemical/biological treatment (CBT) process to efficiently remediate soils and sludges contaminated with hazardous compounds such as polynuclear aromatic hydrocarbons (PAHs), volatile hydrocarbons (e.g., BTEX), and polychlorinated biphenyls (PCBs). Bench-scale studies as well as the field-scale tests show that the CBT process is effective in significantly enhancing the rate as well as the extent of degradation of these contaminants.

In this paper, the results of bench-scale tests conducted with a variety of PAHs and a set of field-scale tests conducted with soils from a former manufactured gas plant (MGP) site (now a Superfund site) that contained coal-tar associated PAHs. The field tests results show that the chemically enhanced bioremediation using the CBT process results in up to 90% improvement over conventional bioremediation for total PAHs (2-6 ring compounds) degradation and over 100% improvement over conventional bioremediation for carcinogenic PAHs (4-6 ring compounds) degradation. In this paper, the preliminary results of the second field test being conducted using the contaminated soils from another MGP site are discussed.

     

Synthesis of the penta-glutamyl derivative of N-[4-[N-[3-(2,4-diamino-1,6-dihydro-6-oxo-5-pyrimidinyl)-propyl]amino]benzoyl]-L-glutamic acid (5-DACTHF). An acyclic analogue of tetrahydrofolic acid

The penta-glutamyl derivative of N-[4-[N-[3-(2,4-diamino-1,6-dihydro-6-oxo-5-pyrimidinyl)propyl]amino]-benzoyl)-L-glutamic acid (1, 5-DACTHF, 543U76) was synthesized by a convergent route. L-γ-Glutamyl-L-γ-glutamyl-L-γ-glutamyl-L-γ-glutamyl-L-γ-glutamyl-L-glutamic acid heptakis t-butyl ester ( 20 ) was prepared in ten steps from L-glutamic acid di-t-butyl ester and N-(benzyloxycarbonyl)-L-glutamic acid α-t-butyl ester. 4-[N-[3-(2,4-Diamino-1,6-dihydro-6-oxo-5-pyrimidinyl)propyl]trifluoroacetamido]benzoic acid ( 6 ), which was synthesized from pyrimidinylpropionaldehyde 3 in three steps, was condensed with 20 , followed by deprotection to provide N-[4-[N-[3-(2,4-diamino-1,6-dihydro-6-oxo-5-pyrimidinyl)propyl]amino]benzoyl]-L-γ-glutamyl-L-γ-glutamyl-L-γ-glutamyl-L-γ-glutamyl-L-γ-glutamyl-L-glutamic acid ( 2 ). Hexaglutamate 2 is a potent inhibitor of glycinamide ribonucleotide transformylase.     

Synthesis of N-[4-[2-(2,4-Diamino-1,6-dihydro-6-oxo-5-pyrimidinyl)-ethylamino]benzoyl]-L-glutamic acid. An acyclic analogue of 5,6,7,8-tetrahydrofolic acid

The synthesis of N-[4-[2-(2,4-diamino-1,6-dihydro-6-oxo-5-pyrimidinyl)ethylamino]benzoyl]-L-glutamic acid ( 2 ), a two carbon analogue of 5-DACTHF ( 1 ) and an acyclic analogue of 5,6,7,8-tetrahydrofolic acid, is reported. The pyrimidinylacetaldehyde diethyl acetal 3 , which was prepared in 2-steps from 2-chloro acetaldehyde diethyl acetal, was converted to 2 in four steps. Compound 2 was less cytotoxic toward Detroit 98 or L cells than 5-DACTHF ( 1 ).     

Solvent-dependent vibrational frequencies and reorganization energies of two merocyanine chromophores

Absorption and resonance Raman spectra have been measured over a wide range of solvents for two merocyanine dyes containing the indoline ("Fischer" base) electron donor group with different accepting groups. One appears to be near the cyanine limit (equal contributions of the neutral and zwitterionic resonance forms to both ground- and excited-state structures) based on electrooptic absorption data showing a very small dipole moment change upon electronic excitation. The resonance Raman spectra of both molecules show significant frequency shifts and intensity redistributions that evolve monotonically with increasing solvent polarity and are consistent with increasing zwitterionic character of the ground-state structure. The vibrational reorganization energies of both molecules, obtained by simulating the absorption band shapes, are smaller in polar solvents than in nonpolar or weakly polar ones, consistent with a more cyanine-like structure at higher solvent polarities. However, the vibrational reorganization energies of both molecules exceed 700 cm(-1) in all solvents, larger than in many true cyanine dyes, and the optical absorption maxima do not correlate well with either solvent polarity or vibrational reorganization energy. This indicates some limitations to the structural conclusions that can be reached from the two-state model for pi-conjugated donor-acceptor systems.     

A Locally-Biased form of the DIRECT Algorithm

In this paper we propose a form of the DIRECT algorithm that is strongly biased toward local search. This form should do well for small problems with a single global minimizer and only a few local minimizers. We motivate our formulation with some results on how the original formulation of the DIRECT algorithm clusters its search near a global minimizer. We report on the performance of our algorithm on a suite of test problems and observe that the algorithm performs particularly well when termination is based on a budget of function evaluations.     

Incorporation of Phytoremediation Strategies into the Introductory Chemistry Laboratory

An undergraduate laboratory exercise appropriate for introductory chemistry courses at the high school or college level is presented. The objective of the laboratory is to introduce the idea that plants can be used to remove contaminants from the environment–a process called phytoremediation. This laboratory connects the disciplines of chemistry and biology while enabling students to learn the skills of measurement, titration, calculation of molarity of an unknown solution, graphing, and interpretation of data.     

Preparation of 1H‐pyrazole‐5‐carboxamides from dilithiated C(α), N‐phenylhydrazones and lithiated ethyl oxanilates or lithiated ethyl oxamate

Dilithiated C(α), N‐phenylhydrazones were prepared in excess lithium diisopropylamide and condensed with either ethyl oxanilate, ethyl 4′‐chlorooxanilate, or ethyl oxamate to give intermediates that were quenched and acid cyclized to substituted lH‐pyrazole‐5‐carboxamides.