摘要:

Some of the reasons for the difficulty of devising a generally valid analytical procedure for polycyclic aromatic sulfur heterocycles (PASHs) are discussed. A procedure for the separation of polycyclic aromatic hydrocarbons and PASHs which has been used for many years is investigated. It is shown that the oxidation with hydrogen peroxide in acetic acid/benzene produces not only the desired sulfones of the PASHs but that also the aromatic rings of polycyclic compounds of all types are oxidized. Low or zero recovery of the analytes is therefore often found. A large number of reagents was tested for the reduction of aromatic sulfones to PASHs in order to find a substitute for lithium aluminum hydride. None was discovered that cleanly affects this conversion. It is strongly recommended that oxidation with hydrogen peroxide not be used for any samples in which aromatic compounds are to be analyzed.

ISSN:0306-7319    

DOI:10.1080/03067319208027038

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The concentration of the sulfur compounds dimethyl sulfide (DMS), dimethyl disulfide (DMDS), and carbon disulfide (CS2) as well as of methyl iodide (CH3I) was determined in surface sea water of the Atlantic Ocean from 30°S to 45°N during an expedition with the German research vessel 'FS Polarstern' using a purge and trap/gas chromatographic system equipped with a flame photometric and an electron capture detector. The most abundant sulfur compound was DMS with a mean concentration of 55 ng S/l. DMDS and CS2could be detected in 14 and 56 out of a total number of 100 sea water samples with concentrations up to 14.7 ng S/l and up to 10.7 ng S/l, respectively. This is the first time that DMDS could be quantified in a number of sea water samples. CH3I was determined in all samples with a mean of 0.6 ng I/l. In three Atlantic sea water samples dimethyl selenide (DMSe) was detected for the first time (concentration range, 1–5 ng Se/l). Its presence was verified by means of an atomic emission detector. DMSe was the only volatile selenium compound found. Contrary to CS2, the concentrations of CH3I and especially of DMS and DMDS are related to the levels of marine primary production. In agreement with this, the DMS concentrations correlated well with those of dimethyl sulfonium propionate (DMSP). However, no clear relationship between CH3I and DMS could be found, indicating a different pathway of biological production.

ISSN:0306-7319    

DOI:10.1080/03067319208027039

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Extensive use of food spices in oriental and Latin American cooking, pharmacy, and perfumery entails the evaluation of trace element contents in them. Instrumental neutron activation analysis (INAA) was used to determine the concentration of 18 trace elements (essential, toxic and non-essential) in six different spices consumed in Rawalpindi/Islamabad area. Turmeric powder and ginger powder were found to contain relatively high amounts of essential elements and low amounts of toxic elements. The comparison of our values with Canadian and Egyptian data shows variation in trace element contents of red pepper, turmeric, coriander and ginger. The estimated dietary intake through food spices show that these may be considered appreciable sources of trace element intake due to their extensive use. With the present studies the investigation of trace element contents of 13 food spices has been completed.

ISSN:0306-7319    

DOI:10.1080/03067319208027040

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Major, minor and trace elements, including Ag, Au, Ca, Cr, Cu, Mg, Mn, Co, Na, Ni, K, Fe, Pb, Sr and Zn, were determined by AAS in milk of some animals, such as cow, camel, goat, ewe and buffalo from Aswan city, as well as of grazing goat and ewe which are feeded by the naturally growing plantsIndiogefra Agrenta, Lotonis Platcarps, andAstragalus Vogelliain Wadi El Allaqi area at the southeastern part of the High Dam Lake (upper Egypt). The present study gives a new picture on trace element concentrations in milk as a result of different environmental conditions such as site, feeding plants and soil contamination. The results show higher concentrations of Na, Mg, Fe, Co, Cu, Mn, Ni, Pb, Sr and Zn in the milk of Aswan ewe than in that of cow, goat, camel and buffalo, while Na, Mg, K, Au, Co, Ni and Pb are found in higher concentrations in the milks of ewe and goat of Allaqi area than those of Aswan city, as a result of the high concentration of these elements in the natural growing plants in Wadi El Allaqi and in the grazing soil.

ISSN:0306-7319    

DOI:10.1080/03067319208027041

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0306-7319    

DOI:10.1080/03067319208027037

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor