The Extraction and Determination of Polynuclear Hydrocarbons in Paraffin Waxes

1963 ◽  
Vol 46 (6) ◽  
pp. 933-941
Author(s):  
John W Howard ◽  
Edward O Haenni
Keyword(s):  
Dimethyl Sulfoxide ◽  
Absorption Spectra ◽  
Partition Coefficients ◽  
Paraffin Wax ◽  
Chromatographic Techniques ◽  
Polynuclear Compounds ◽  
Pure Compounds ◽  
Background Material ◽  
Paraffin Waxes

Abstract A method for the isolation and determination of polynuclear hydrocarbons in paraffin wax has been developed in which polynuclear compounds are extracted from the wax by diluting a melted wax solution with an aliphatic solvent and extracting the resulting solution with dimethyl sulfoxide. Paper chromatographic techniques are used to separate the compounds from the background material extracted from the wax. The hydrocarbons are rechromatographed until their ultraviolet absorption spectra are comparable to those obtained for pure compounds. Recoveries of 19 polynuclear hydrocarbons added to 100 g samples of paraffin wax at levels of 0.1 ppm or less ranged from 62 to 96%. Recoveries of benzo(a)pyrene and dibenz(a, h) anthracene added to 100 g or 500 g of wax at levels as low as 0.02 ppm or 0.005 ppm, respectively, were in the range 90—100%. The variations in the recoveries are apparently caused by differences in the partition coefficients of the hydrocarbons between the aliphatic solvent and dimethyl sulfoxide and at lower levels by the tendency of some of the compounds to be oxidized. The method has been utilized for the determination of polynuclear hydrocarbons in commercial waxes.

Determination of Benzene in Polypropylene Food-Packaging Materials and Food-Contact Paraffin Waxes

1991 ◽  
Vol 74 (2) ◽  
pp. 367-374
Author(s):  
Sandra L Varner ◽  
Henry C Hollifield ◽  
Denis Andrzejewski
Keyword(s):  
Gas Chromatography ◽  
Food Packaging ◽  
Fused Silica ◽  
Paraffin Wax ◽  
Gas Chromatography Mass Spectrometry ◽  
Food Contact ◽  
Limit Of Quantitation ◽  
Headspace Gas ◽  
Paraffin Waxes

Abstract An analytical procedure was developed for determination of benzene in polypropylene food packaging and was adapted for determination of benzene in commercial paraffin waxes Intended for food-contact use. The polymer was dissolved in hexadecane at 150°C. The wax was melted in an 80°C oven. A simple helium-sparging apparatus was used to remove the volatile chemical from the polymer or wax. The contaminant was collected In methanol, distilled water was added, and the resulting solution was analyzed by headspace gas chromatography. The Instrument was equipped with a 30 m fused silica open tubular capillary column and a photoionization detector. Average recoveries of benzene from polymer and paraffin wax at low parts-per-billion concentrations were 63 and 70%, respectively. Limits of detection and quantitation for analysis of polypropylene were 8 and 17 ppb, respectively; the limit of quantitation for analysis of paraffin wax was 2 ppb. in several commercial polypropylene products examined, benzene levels ranged from none detected to 426 ppb. In 3 commercial waxes examined, concentrations of 16-73 ppb benzene were determined. The presence of benzene was confirmed by gas chromatography/mass spectrometry

Determination of Micro Quantities of Some Chlorinated Organic Pesticide Residues in Edible Fats and Oils

1963 ◽  
Vol 46 (2) ◽  
pp. 182-186
Author(s):  
Martin Eidelman
Keyword(s):  
Dimethyl Sulfoxide ◽  
Pesticide Residues ◽  
Edible Oils ◽  
Detection System ◽  
Fats And Oils ◽  
Fish Oils ◽  
Edible Fats ◽  
Background Material ◽  
Chlorinated Organic

Abstract The dimethyl sulfoxide procedure was extended to eleven edible oils and fish oils. After cleanup, the detection system of choice may be used. If extracts of samples larger than 20 g are injected into the microcoulometric detection system, halogenated background material will make evaluation difficult. In fish oils, when paper chromatography is used for evaluation, an Rf indicating aldrin must be further investigated, since it is possible that a spot at this Rf might be background material.

Spectrophotometric study of the reactions of lanthanoids with bromopyrogallol red in the presence of cation active tensides

1982 ◽  
Vol 47 (2) ◽  
pp. 503-508 ◽  
Author(s):  
Irena Němcová ◽  
Pavla Plocková ◽  
Tran Hong Con
Keyword(s):  
Absorption Spectra ◽  
Photometric Determination ◽  
Spectrophotometric Study ◽  
Ternary Complexes ◽  
Optimal Conditions ◽  
Bromopyrogallol Red ◽  
Binary Complexes

The absorption spectra of the binary complexes of lanthanoids with bromopyrogallol red were measured and the formation of ternary complexes with cation active tenside, Septonex, was studied. Optimal conditions were found for the formation of these complexes and the possibility of their use in the photometric determination of lanthanoids was demonstrated on several examples.

Interphase distribution of 2-furylethylenes

1985 ◽  
Vol 50 (8) ◽  
pp. 1642-1647 ◽  
Author(s):  
Štefan Baláž ◽  
Anton Kuchár ◽  
Ernest Šturdík ◽  
Michal Rosenberg ◽  
Ladislav Štibrányi ◽  
...  
Keyword(s):  
Partition Coefficient ◽  
Partition Coefficients ◽  
Transport Rate ◽  
Phase System ◽  
Two Phase ◽  
Interphase Distribution ◽  
Distribution Kinetics ◽  
System 1 ◽  
Kinetics Of

The distribution kinetics of 35 2-furylethylene derivatives in two-phase system 1-octanol-water was investigated. The transport rate parameters in direction water-1-octanol (l1) and backwards (l2) are partition coefficient P = l1/l2 dependent according to equations l1 = logP - log(βP + 1) + const., l2 = -log(βP + 1) + const., const. = -5.600, β = 0.261. Importance of this finding for assesment of distribution of compounds under investigation in biosystems and also the suitability of the presented method for determination of partition coefficients are discussed.

scholarly journals Evidence for two asymmetric conformational states in the human erythrocyte sugar-transport system

1975 ◽  
Vol 145 (3) ◽  
pp. 417-429 ◽  
Author(s):  
J E Barnett ◽  
G D Holman ◽  
R A Chalkley ◽  
K A Munday
Keyword(s):  
Glucose Transport ◽  
Transport System ◽  
Human Erythrocyte ◽  
Partition Coefficients ◽  
External Medium ◽  
Sugar Transport ◽  
Conformational States ◽  
Glucose Transport System ◽  
Oil Water

6-O-methyl-, 6-O-propyl-, 6-O-pentyl- and 6-O-benzyl-D-galactose, and 6-O-methyl-, 6-O-propyl- and 6-O-pentyl-D-glucose inhibit the glucose-transport system of the human erythrocyte when added to the external medium. Penetration of 6-O-methyl-D-galactose is inhibited by D-glucose, suggesting that it is transported by the glucose-transport system, but the longer-chain 6-O-alkyl-D-galactoses penetrate by a slower D-glucose-insensitive route at rates proportional to their olive oil/water partition coefficients. 6-O-n-Propyl-D-glucose and 6-O-n-propyl-D-galactose do not significantly inhibit L-sorbose entry or D-glucose exit when present only on the inside of the cells whereas propyl-beta-D-glucopyranoside, which also penetrates the membrane slowly by a glucose-insensitive route, only inhibits L-sorbose entry or D-glucose exit when present inside the cells, and not when on the outside. The 6-O-alkyl-D-galactoses, like the other nontransported C-4 and C-6 derivatives, maltose and 4,6-O-ethylidene-D-glucose, protect against fluorodinitrobenzene inactivation, whereas propyl beta-D-glucopyranoside stimulates the inactivation. Of the transported sugars tested, those modified at C-1, C-2 and C-3 enhance fluorodinitrobenzene inactivation, where those modified at C-4 and C-6 do not, but are inert or protect against inactivation. An asymmetric mechanism is proposed with two conformational states in which the sugar binds to the transport system so that C-4 and C-6 are in contact with the solvent on the outside and C-1 is in contact with the solvent on the inside of the cell. It is suggested that fluorodinitrobenzene reacts with the form of the transport system that binds sugars at the inner side of the membrane. An Appendix describes the theoretical basis of the experimental methods used for the determination of kinetic constants for non-permeating inhibitors.

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