摘要:

Solid polycyclic aromatic hydrocarbons with 4–7 rings on metal, glass, ceramic, and plastic substrates were desorbed and ionized in air with a quadrupled Nd-YAG laser. Gaseous product ions were analyzed at ambient conditions in air directly using ion mobility spectrometry. Ablation rates for perylene on borosilicate glass were estimated as 0.01 ng/mm2 per pulse and standard deviation for peak heights with roughly 1 ug/mm2was 34 %. Substrate interference was avoided by using an unfocused laser beam at 0.5–1 mJ/pulse although gaseous ions also could be generated from substrates with a focused beam at 1 mJ/pulse.

ISSN:0003-2719    

DOI:10.1080/00032718808081236

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

We participated in the interlaboratory studies conducted by the National Bureau of Standards/Department of Energy (NBS/DOE) Analytical Characterization Group in which shale oil and diesel particulates were analyzed for three ring to six ring polynuclear aromatic hydrocarbons (PAH). Diesel particulates were extracted by Soxhlet or ultrasonic extraction. The PAH fraction was isolated with Sephadex LH-20 gel filtration chromatography and silica gel adsorption chromatography. The individual PAH was identified and quantitated with a gas chromatography/flame ionization detector and computerized gas chromatography/mass spectrometry. The combination of gel filtration and adsorption chromatography was found to be effective in isolating PAH from various complex sample matrices for further instrumental analysis. The results compared favorably with methods used among the other participating laboratories.

ISSN:0003-2719    

DOI:10.1080/00032718808081237

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The color reaction between Xylenol orange (XO), zirconium (IV) and fluoride ions in the presence of various surfactants alone or in combination was studied at various pH. The XO -zirconium)IV)-fluoride ion ternary complex in mixed micellar media containing a low concentration of N-hexadecylpyridinium chloride (HPC) as a cationic surfactant and large amounts of (poly{oxyethylene)dodecyl ether (Brij 35) as a nonionic surfactant at weakly acidic media was found to be the most stable, and showed a remarkable bathochromic shift and clear contrast against a reagent blank. The maximum absorbance was at 600 nm in the mixed micellar media at pH 3.5, and the apparent molar absorptivities at 600 nm were 7.0 × 1041 mol−1cm−1for zirconium(IV) and 1.4 × 1041 mol−1cm−1for fluoride ion. The calibration curves covered the ranges of 0.5 ∼ 20.0 μg/10 ml zirconium! IV) and 0 ∼ 20.0 μg/10 ml fluoride ion with the Sandell sensitivities being 0.0013 μg/cm2for zirconium(IV) and 0.0016 μg/cm2for fluoride ion.

ISSN:0003-2719    

DOI:10.1080/00032718808081238

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The potential applicability of surfactant solutions as carrier streams in flow injection analysis is examined. The reaction rates determined for the base catalyzed hydrolysis of acetylsalicylic acid in aqueous, micellar and microemulsion solutions show a rate enhancement of 40% for the static microemulsion system when compared to the aqueous solution. However, when the identical microemulsion solution is employed as a carrier stream in flow injection analysis with ultraviolet detection, this enhancement in rate is not observed. To our knowledge, all previous work employing microemulsions in FIA has been concerned only with detection enhancement, here we present direct comparisons between aqueous and microemulsion carriers concerning rates of reaction, peak dispersion and analytical figures of merit. The loss in relative sensitivity can be traced to the increased dispersion in the microemulsion system (D = 14.36) when compared to the aqueous carrier (D = 12.52). Additionally, an increased skewness was observed in the peaks obtained with a microemulsion carrier, yielding further information about the physical dispersion process occuring in the sample plug.

ISSN:0003-2719    

DOI:10.1080/00032718808081239

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Liquid-liquid partition coefficients (KD) of both Cr(III) and Pd(II) complexes of several β-dlketones between dodecane and a water-methanol mixture have been determined by a combined method of batch technique and high performance liquid chromatography (HPLC). The KDof each metal complex is enhanced as the methanol content of the mixed liquid phase decreases. In bothhomologs of the Cr(III) complexes and the Pd(II) complexes, KDincreases with an increase in the molecular size of the complex, although Cr(III) complex tends to have smaller KDthan the Pd(II) complex whose molecular size is comparable with that of the Cr complex.

ISSN:0003-2719    

DOI:10.1080/00032718808081240

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A comparative study of the chromatographic behaviour of anions, iodide, sulphide, phosphate, arsenate, arsenite, vanadate, chroraate, dichromate, thiosulphate, thiocyanate, ferricyanide and ferrocyanide on papers impregnated with hydrated bismuth oxide and untreated Whatman no, 1 papers has been made by employing identical aqueous, non-aqueous and mixed solvent systems. Sharp and compact spots were obtained with impregnated papers whereas the opposite applied to plain papers. Various analytically important binary and ternary separations are reported.

ISSN:0003-2719    

DOI:10.1080/00032718808081241

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Indium(III) reacts with α-diketone bisphenylthiosemicarbazones derived from glyoxal, biacetyl and methylglyoxal to form 1:1 and 1:2 (In: reagent) complexes in acid and basic medium, respectively. The effect of experimental variables was studied in detail on the acid site, and a new method for the spectrophotometric determination of indium(III) with meth-ylglyoxal bis(4-phenyl-3-thiosemicarbazone) (MGBPT) is proposed. The yellow 1:1 In-MGBPT complex is formed at pH 3.5–6 in a solution containing a 60 % V/V of dimethylforrnamide. The nature of the complex (ε = 27,100 1 mol−1cm−1at 465 mm) and the effect of interferences were studied.

ISSN:0003-2719    

DOI:10.1080/00032718808081242

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A colour reaction has been studied for resin bead detection of phenylhydrazine with copper(II) nitrate. The interaction of phenylhydrazine with periodic acid has been studied for its spectrophotometric determination. The detection limit is 10μg. Beer's law is obeyed in the concentration range 0.1 to 3.0 mg of phenylhydrazine.

ISSN:0003-2719    

DOI:10.1080/00032718808081243

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A method based on the decoloration of dilute chloroform solutions of ura nyl quinolin-8-olate by shaking with aqueous solution of anions is proposed for the spectrophotometric determination of carbonate. The effects of several variables on the decoloration (pH, shaking time, volume ratio, etc.) were established. The spectral stability of an organic solution of the metal chelate is increased with an excess of quinolin-8-ol in the organic phase, and it avoids its stripping with water. The decoloration of chloroformic solutions varies linearly with the carbonate concentration between 10 and 50 μg.ml−1in the aqueous phase (apparent molar absorptivity is found to be 2.03×103l.mol−1.cm−1at 390 nm). Interferences of many foreign ions (cations and anions) are also established. The method is relatively free from anion interferences.

ISSN:0003-2719    

DOI:10.1080/00032718808081244

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Hafnium (IV) was selectively extracted from 0.45–0.55 M HC1 media as its chelate with N-p-methoxyphenyl-2-furylacrylo-hydroxamic acid (MFHA) into chloroform. Xylenol orange was added to the extract to form an intensely coloured ternary complex measurable spectrophotometrically at 545 nm (ε = 8.3×1041 mol−1cm−1) with a sensitivity better than 0.002 ppm. For atomic absorption spectrometric determination, hafnium was extracted with MFHA into methyl isobutyl ketone and measured with 286.6 nm resonance line in the nitrous oxide-acetylene flame. The methods were applied to the analysis of hafnium in alloys, plant tissues, animal tissues and natural waters. The MFHA-xylenol orange reagent combination was chosen after studying ten hydroxamic acids and five chromogenic reagents.

ISSN:0003-2719    

DOI:10.1080/00032718808081245

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor