Infrared spectroscopic investigations of humic substances and their metal complexes

A study has been made on the infrared spectra of lowland peats and purified humic, hymatomelanic and fulvic acids, as well as their acetylated derivatives and metal complexes. Extraction and purification may modify humic acids of untreated peats only to a small extent. Acetylation of fulvic and humic acids with acetic acid anhydride resulted mainly in the reaction of phenolic hydroxyl and quinone groups. Similarities of the spectra of the individual humic substances point to similar structures, differing only in the number of functional groups and the degree of aggregation. Metals are bound by humic substances mainly in metalcarboxylate bonds. The degree to which these bonds are ionic or covalent can be determined by the antisymmetric carboxylate stretching frequencies.     

Mineralogisch-chemische umwandlungen bei der verwitterung pyroklastischer gesteine auf teneriffa (Kanarische Inseln)

In a weathering profile on pyroclastic material four phases of volcanic activity could be defined by mineralogical analysis. Halloysite in 10 Å- and 7 Å-modifications is the predominant new mineral formed by weathering processes. Various degrees of development of this clay-mineral were found in scanning microscopy.The paragenesis of gibbsite, ilmenite and anatase is characteristic for horizons of most intense weathering. The gibbsite found in distinct layers indicates an alteration of climatic conditions between eruption-stages 3 and 4. Absolute age determinations on potash-felspars from a layer of stage 3 yield 1.53 mio. years (+ 10%).     

Comparison of dieldrin, lindane, and DDT extractions from serum, and gas-liquid chromatography using glass capillary columns.

Rats were given an oral dose of 14C-labeled chlorinated pesticides to obtain serum containing p,p'-DDT, dieldrin, or lindane. Simple hexane and formic acid-hexane extraction methods, involving pretreatment of the serum with formic acid, were compared by radiometric and by paper chromatographic and gas chromatographic analysis. In vivo binding of chlorinated pesticides to constituents of the serum does not necessarily prohibit their isolation by simple hexane extractions, provided that the extraction is very vigorous and at least 5 min long. Stable emulsions were broken by cooling in liquid nitrogen or Dry Ice-acetone. The hexane extraction method described yields quantitative recovery of the pesticides studied, whereas the formic acid-hexane method is quantitative for p,p'-DDT, 93% for dieldrin, and 89% for lindane. Gas chromatographic comparison of both methods, using human serum, shows that the hexane method extracts 16% more beta-BHC, 7% more dieldrin and HCB, and 4% more p,p'-DDE from serum than does the formic acid-hexane method. The difference for p,p'-DDT is not significant. Gas chromatography with glass capillary columns and an all-glass solids injection system yielded detection limits as low as 15 fg. Data show that the use of an internal standard considerably improves the precision of quantitation.     

Detection of O,O-diethyl-O-(2,5-dichlorophenyl) phosphorothioate and O,O-diethyl-O-(3,6-dichloro-2-pyridyl) phosphorothioate in meat fat.

Two previously unreported organophosphorus residues have been detected in meat fat. The first, O,O-diethyl-O-(2,5-dichlorophenyl) phosphorothioate, apparently results from the debromination of bromophos-ethyl, while the other, O,O-diethy-O-(3,6-dichloro-2-pyridyl) phosphorothioate, presumably arises by the monodechlorination of chlorpyriphos. Mass spectral evidence is presented in support of the assigned structures and gas-liquid chromatographic retention data for the residues and their oxygen analogs are provided.     

Nitrogen and Italian ryegrass. 3. Growth up to 14 weeks: yields, proportions, digestibilities and nitrogen contents of crop fractions, and tiller populations

The regrowth of Italian ryegrass following a cut in late April was studied at weekly intervals up to 14 weeks. There were four levels of applied N: 28, 84, 140 and 196 kg ha^-1. The proportion of green leaf blade declined from 80% of DM yield after 2 or 3 weeks of regrowth to 5% after 13–14 weeks. About three-quarters of the increase in DM yield of total herbage from week 3 to week 11 was attributable to increased yield of ‘stem’. The level of applied N had little effect on the proportion of crop fractions except during the period immediately before and after the begiiming of ear emergence when the higher rates of N increased the proportion of ‘stem’ and reduced that of green leaf. The most digestible crop fractions were green leaf, inflorescence and immature ‘stem’. D-value of ‘stem’ declined by about 20 units from week 1 to week 14, while D-value of green and dead leaf declined at about half this rate and there was little or no decline in D-value of inflorescence. The N content of green leaf was consistently higher than that of the other fractions. The N content of ‘stem’declined markedly to around 0.5% by week 12. The N content of dead leaf and inflorescence was intermediate between that of green leaf and mature ‘stem’. The N content of all fractions was increased by applying more N. The tiller population increased during the flrst 3 weeks of regrowth and declined during the next 4. Applying more N increased both tiller population and weight per tiller.     

Effects of repeated use of an area of heather Calluna vulgaris (L.) hull moor at Kindrogan,Scotland, for teaching purposes

A triangular plot of heather moor at Kindrogan was used for teaching botanical analysis for eight years, using the same set of random coordinates to locate sample points. Because of the method of point location, there was a gradient of trampling pressure across the plot, and there were also parts of the plot that were never analysed. At the end of the eight-year period heather cover and mean height were found to have declined with increasing levels of trampling. Mean numbers of species/m² did not however decline, and were actually minimal on untrampled ground. With moderate levels of trampling, quadrats that had been analysed for eight years contained more heather litter than those that had not been analysed before. No decline in species frequencies was found in previously analysed quadrats. The value of the plot for teaching purposes does not seem to have declined, and may have actually increased over the period of use.     

Stratigraphy and land use of the Post-Diamond Hill Paleosol,western Oregon

The Post-Diamond Hill Paleosol generally underlies Late Pleistocene sediments of the Willamette Formation. However, in numerous localities in the Willamette Valley, reddish gray clay paleosols either outcrop at the surface or occur within soil profile depth. Then they are part of soils of the modern landscape. Where the paleosols outcrop, the soils are mostly Typic Pelloxererts in the fine, montmorillonitic, mesic family. Because of the nature of the paleosols, these soils are poorly suited for nearly all intensive uses; the dominant use is hay and pasture.     

Interactions between Escherichia coli and allophane—I. Adsorption

Sorptive interactions between Escherichia coli (ATCC 11303B) and a purified allophane clay fraction were studied quantitatively using electronic particle counting and electrophoresis. Adsorption was influenced by pH and ions present at the allophane surface. These effects could be rationalized by considering changes in the net surface charge of the components. Electronic particle counting studies at pH 5.5 and above gave adsorption isotherms that obeyed single-term Langmuir kinetics. At pH 4.5, a more complex two-step isotherm was obtained, which was attributed to aggregation of unadsorbed cells by Al solubilized from the allophane surface.     

Gas-liquid chromatographic-mass spectrometric determination of alpha- and beta-naphthylamines in FD&C Red No. 2 (amaranth)

A method is described for the simultaneous quantitation of trace amounts of alpha- (alpha-NA) and beta-naphthylamines (beta-NA) with detectability in the 0.1 ppb range and sensitivity of 50 picomoles in certified food grade amaranth (FD&C Red No. 2; C.I. Food Red 9; CI 16185). The amaranth sample is extracted with benzene, and the evoporated residue is derivatized with perfluorooctanoic anhydride. The resulting derivatives are separated by gas-liquid chromatography and identified and quantitated by mass spectrometric monitoring of the m/e at 539.04. The method was used for quantitation of alpha-NA and beta-NA in randomly chosen samples of amaranth. Of 11 samples from different manufacturers, 5 were free of the beta-isomer; the remaining samples contained up to 1.2 ppb beta-NA. The concentration of alpha-NA ranged from no detectable amount to 970 ppb; the majority of the samples contained less than 7 ppb.     

Analysis of fat-soluble vitamins. XXIII. High performance liquid chromatographic assay for vitamin D in vitamin D3 and multivitamin preparations.

Vitamin D is determined in preparations containing other fat-soluble vitamins by high performance liquid chromatography (HPLC). The unsaponifiable residue is extracted and separated from interferences by reverse phase chromatography; the fraction corresponding to vitamin D3 is collected and quantitated using normal phase chromatography (amylalcohol-n-hexane as mobile phase) by measuring the vitamin D3 and pre-vitamin D3 peaks at 254 nm. Previtamin D3 content is calculated as vitamin D3 with a conversion factor (determined on the equipment used). Application of the method to vitamin AD3 mixtures in oils gives 98-102% recovery. The reproducibility, using an external standard, is 2-3%, calculated as the coefficient of variation; with an internal standard, the coefficient of variation is 1-1.5%. The method measures potential vitamin D3 content in preparations containing greater than or equal to 200 IU/g in the presence of all known vitamin D3 isomers, vitamin A, and vitamin E.