摘要:

The effects of cationic hexadecyltrimethylammonium chloride (CTAC), nonionic polyoxyethylene (9.5)p-1, 1, 3, 3-tetramethylbutylphenol, Triton X-100 (TX-100), and anionic sodium dodecylsulfate (NaLS) surfactant micelles upon the spectrofluorimetric determination of pyrene is described. It was found that the intensity of the pyrene fluorescence is enhanced from 3 to 16 times in the presence of the micellar systems. Possible reasons for this micellar induced enhanced fluorescence are discussed. The spectral parameters, fluorescence lifetimes, quantum yields, lower detection limits, and analytical figures of merit for pyrene in CTAC, NaLS, TX-100, ethanol, and water are compared. The detection limit of pyrene in the presence of micelles (∼1.0 × 10−10M) is about an order of magnitude lower than that possible in alcohol alone. A brief discussion on the predicted general applicability of this new technique in fluorimetric analyses is also given.

ISSN:0003-2719    

DOI:10.1080/00032718208064379

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Vaporizing palladium from a graphite platform increases peak area and in some cases peak height sensitivity. The absorption pulse is considerably delayed so that vaporization takes place under isothermal conditions. Many vapor phase interferences are thus overcome. The relative sensitivity of the 340.5 nm non-resonance line exceeds that of the 276.3 nm resonance line. The mass of the platform as well as its contact surface with the graphite tube was found to exhibit a marked influence on peak height sensitivity. Calibration curves are more linear than with vaporization from the wall.

ISSN:0003-2719    

DOI:10.1080/00032718208064380

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Chromium ions,viz., chromic (Cr±3=III) and chromate (Cr±6= VI), can be reliably, conveniently, reproducibly, and quickly separated and detected by the use of conventional paired-ion, reversed phase (RP) high performance liquid chromatography (HPLC) together with refractive index (RI) and/or inductively coupled plasma emission spectroscopic (ICP) detection. A number of novel paired-ion approaches have now been developed, using PIC A (tetrabutylammonium hydroxide) or PIC B (sodium n-alkyl sulfonate) separately in the mobile phase. This allows for the retention of each Cr species depending on the particular ion pairing reagent being used, while the remaining Cr ion elutes in the solvent front. Changing the ion pairing reagent reverses the overall situation. The total time for each HPLC analysis is about 10 mins. ICP detection provides for a complete, overall method of speciation for both Cr (III) and Cr (VI)viatwo separate injections, together with quantitation for both species. This method of using paired-ion RP-HPLC can easily be applied to other mixtures of inorganic cations and anions, presumably with equally successful results. Minimum limits of detection are computed for chromateviadirect-ICP, using at least two basic methods for such computations. It is suggested that virtually all chromatographic detection limits can be significantly improved by the application of newer, spectroscopic based methods of automated computation of detection limits.

ISSN:0003-2719    

DOI:10.1080/00032718208064381

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

A new spectrofluorimetric method for the determination of zinc using pyridoxal nicotinylhydrazone as the reagent has been developed. This system forms a ternary complex with ammonia, ethylenediamine or pyridine with a stoichiometry ratio of 1:1:1. The interferences of foreign ions have been determined.

ISSN:0003-2719    

DOI:10.1080/00032718208064382

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Procedures for enrichment of non-volatile chlorinated aromatic pollutants from fat, water and milk are described.14C-DDT was used as a model compound in recovery experiments. A several thousand-fold enrichment of DDT added to butter was achieved by two consecutive straight-phase chromatographies on Lipidex 5000.

ISSN:0003-2719    

DOI:10.1080/00032718208064383

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

A sensor for potentiometric titrations was prepared by coating a spectroscopic graphite rod with a solution of poly(vinyl chloride) and dioctylphthalate in tetrahydrofuran. The reference was a Ag/AgCl single-junction electrode. The sensor was used in the following potentiometric titrations:

ISSN:0003-2719    

DOI:10.1080/00032718208064384

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Maintenance of a constant flow rate has been a long-standing problem with hi-vol samplers used to collect ambient aerosol. Numerous types of commercially available flow controllers are currently in use. A passive flow controller has now been developed that operates without external power or electrical circuits, and, when coupled with an AC inductive motor and cyclone blower, effectively controls flow rate between 100 and 1500 L/min.

ISSN:0003-2719    

DOI:10.1080/00032718208064385

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

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

ISSN:0003-2719    

DOI:10.1080/00032718208064378

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor