摘要:

An on-line liquid chromatography/tandem quadrupole (LC/MS/MS) instrument was used to monitor aromatic acids in a complex mixture. This mixture contains components known to exist as humic acid degradation products. The use of the tandem quadrupole removed LC solvent interferences and selected the protonated molecular ion of a particular acid to undergo collisional activation. The resulting fragments provide the specificity to detect target acids; the CA spectrum is “clean” and resembles the reference spectrum. This specificity is unobtainable by LC/MS alone. Present LC/MS/MS detection limits are 5 μg injected on column (50 ng in source) for a full scan detecting fragment ions greater than 5% relative intensity.

ISSN:0003-2719    

DOI:10.1080/00032718208064358

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Liquid ion exchangers such as tri-n-octyl amine (TOA), tri-iso-octylamine (TTOA) and Aliquat 336 have been used in this laboratory for analytical separation of vanadium(V) and niobium(V)1, indium(III), thallium(III)2, thorium(IV), cerium(IV)3from succinate solutions. Extension of this study has revealed that benzene solutions of TOA, TIOA and Aliquat 336 could be used for anion exchange extraction of quadrivalent titanium and zirconium from succinate solution. The metal ions from the organic phase are stripped and determined spectrophotometrically.

ISSN:0003-2719    

DOI:10.1080/00032718208064359

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

A simple analytical procedure is described for the quantitative determination of low levels of difenzoquat in water. It involves trace enrichment of difenzoquat with a C18SEP-PAK reverse phase cartridge, followed by high performance liquid chromatographic determination with ultraviolet detection at 255 nm. The recoveries from the laboratory spiked samples are above 88%. The practical detection limit by this method is 2 ppb.

ISSN:0003-2719    

DOI:10.1080/00032718208064360

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Suitable TLC separation scheme for eleven organo-phosphorous pesticides on silica gel G plates impregnated with metal salt as well as with phenol, using the solvent system-n-hexanexylene-ethyl acetate-acetone (50:15:5:18) has been worked out. The visualization or the spots was done by exposure of the plate to iodine vapours.

ISSN:0003-2719    

DOI:10.1080/00032718208064361

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The determination of arsenic through employing non-dispersive atomic fluorescence spectrometry that follows a hydride generation pretreatment technique has been investigated. A laboratory made graphite furnace atomizer was used as an atom reservoir. The detection limit of arsenic (III) was 0.01 ng. The linear analytical range covered about three orders of magnitude of concentration. The present method has been successfully applied to the determination of arsenic in steel samples.

ISSN:0003-2719    

DOI:10.1080/00032718208064362

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Tetrakis N-dimethylaminoethylene (TMAE) has been evaluated as a reagent for chemiluminescene (CL) determination of oxygen. The experimental setup is designed so that oxygen diffuses across a membrane to react with TMAE yielding CL. The signal for 100% oxygen using a TFE Teflon membrane with an area of 5 cm2and 1.5 mls of pure TMAE is nine orders of magnitude greater than the detector noise. In the presence of 100% oxygen, the signal decreases due to TMAE consumption with a half-life of about six hours. The time to reach steady state response when oxygen levels change is less than a minute. A variety of membranes and reagent formulations have been evaluated in attempts to increase the duration of CL and to improve the response time.

ISSN:0003-2719    

DOI:10.1080/00032718208064363

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

This paper reports the extraction of the ion-pair formed by the tetrabutylammonium cation and the copper complex with thiocyanate from aqueous to MIBK solutions. The variables which affect the extraction efficiency were investigated and the optimal conditions for the efficiency to be almost 100 per cent were determined. The extraction can be accomplished between pH 1 and 7 and an excess of ammonium thiocyanate and tetrabutylammonium chloride is necessary. The absorption spectrum of the ion-pair in MIBK has a maximum at 510 nm. At 510 nm the absorbance is proportional to the concentration of copper in solution. Thus, the spectrophotometric determination of copper is possible, after the extraction by MIBK. Beer's Law is verified for a range between 3.8 × 10−5and 7.6 × 10−4M. after interferences were investigated, the precision and accuracy of this method were checked by determining the copper content in an alloy whose composition was certified by British Chemical Standards.

ISSN:0003-2719    

DOI:10.1080/00032718208064364

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The dissociation constants of 4- (4,5 -dimethyl -2-thiazolylazo) resorcinol (DMTAR) and formation constant of its complexes with Cu (II) were measured spectrophotometrically. The utility of DMTAR as the metallochromic indicator for Cu (II) in EDTA titrations is comparable to 4 - (2 -thiazolylazo) resorcinol (TAR).

ISSN:0003-2719    

DOI:10.1080/00032718208064365

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

A system for studying low-temperature degradation of PVC by monitoring HCl evolution is described. The sample is heated in a Du Pont Model 951 Thermogravimetric Analyzer from ambient to 150[ddot]C, and the fractions are collected by means of an AutoAnalyzer® turntable which is synchronized with the TGA instrument. Either air or N2is used as a sweep gas. This system allows for the precise collection of fractions versus time and temperature. The first fraction contains HCl released from room temperature to 120[ddot]C. Fractions are collected every 5[ddot]C (and 5 minutes) from 120[ddot] to 150[ddot]C, and several additional fractions are collected isothermally at 150[ddot]C. The fractions are then analyzed for chloride with an AutoAnalyzer® connected to a cell containing a chloride specific ion electrode and a fluoride reference electrode. The system is calibrated with standard chloride solutions ranging in concentration from 0.5 to 20 ppm. Samples are analyzed at a rate of 24 per hour. The system is capable of analyzing 60 per hour. Data are given illustrating the precision of both the chloride analysis and the total pyrolysis-analysis system. Also, data are shown comparing an untreated PVC sample to one containing an oxidation inhibitor. As expected, the data show that the inhibitor-containing sample is more stable to 150[ddot]C than the untreated sample. The advantages of this system are: (1) High sensitivity which allows for the detection of HCl evolution at low temperatures. Because of the good sensitivity, the method is very useful for testing the thermal stability of experimental compounds. (2) Ease of operation since the AutoAnalyzer® makes it unnecessary for operator manipulation during pyrolysis and chloride analysis. (3) Precise control of pyrolysis time, temperature, and programming rate.

ISSN:0003-2719    

DOI:10.1080/00032718208064366

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:10.1080/00032718208064357

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor