摘要:

The departure from linear response which often occurs at dilute fluoride concentrations of the calibration curve reduces the sensitivity of the electrode. The linear portion of the standard curve may be extended to lower fluoride levels by dilution of the buffer itself. TISAB III M. tri-Ammonium citrate (TAC) is the superior of the eleven buffer systems examined in terms of masking ability. Of the potentially interfering species studied, only A1 and Mg pose interference problems.

ISSN:0003-2719    

DOI:10.1080/00032718108055488

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

A method is described for the determination of potassium in seawater and marine sediment porewater. After precipitation of the halogen ions with AgNO3, potassium is precipitated with sodium tetraphenylborate. The excess tetraphenylborate is then determined by AgNO3titration, using a silver electrode for end-point detection. Application of this method to seawater samples as small as 1 cm3, gave accuracy and precision of better than 1%.

ISSN:0003-2719    

DOI:10.1080/00032718108055489

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

A simple method for the direct determination of silica in drinking, sea and boiler water was developed. It is based on interfacial preconcentration of silicomolybdate at the electrode (HMDE) and subsequent voltammetric determination. Silica reacts with molybdate at pH 1.6 ± 0.1 to form silico molybdate. By addition of methylethylketone silicomolybdate is completely converted to the β-form. Citrate addition masks any phosphate, if present, and also excess of molybdate. By keeping the initial potential of the HMDE at −0.2 V for 2 min the silicomolybdate is accumulated by adsorption in the interface. Then its bulk concentration is determined by measuring the peak height at −0.36 V. Traces of silica in drinking, sea and boiler water are determinable down to 1 × 10−7M or 6.4μg/l SiO2.

ISSN:0003-2719    

DOI:10.1080/00032718108055490

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

A simple d.c. are emission spectrographic method is described for the determination of 12 trace impurities in phosphor grade CaWO4in the range 5 to 250 ppm. A charge of 25 mgs containing sample mixed with graphite in the ratio 1:3 is excited in a 10 amp d.c. arc. Scandium is used as the internal standard. The precision of the method is ± 15%. Detailed discussion on the selection of the final parameters has been given with supporting data.

ISSN:0003-2719    

DOI:10.1080/00032718108055491

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Laser-induced fluorometric analysis of ultratrace levels of uranium in industrial environmental samples is compared with commonly used spectroscopic techniques for uranium analysis.

ISSN:0003-2719    

DOI:10.1080/00032718108055492

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

A personal sampling and analytical method for ethylene glycol aerosol and vapor in air was developed and tested. The personal sampler contains a glass fiber filter followed by two sections of silica gel. Samples are analyzed by gas chromatography. Ethylene glycol vapor at concentrations ranging from 4.2 to 327 mg/m3for 3-L air samples can be measured. Ethylene glycol can evaporate from the filter during air sampling at 25 °C and enter the silica gel tube.

ISSN:0003-2719    

DOI:10.1080/00032718108055493

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

A GC method using a flame thermionic detector (FTD) with a RbSO4source to determine nitrosamines is described. The method is sensitive enough to be used for a preliminary screening of foodstuffs for the presence of volatile nitrosamines. The lowest detection limit is 0.1 ng for DMNA, DENA, or DPNA, with a linear range of 0.1 − 100 ng determinable. The method has a favorable stability; the factors affecting its sensitivity, e.g. the H2flow rate, column temperature and the solvent used, have been studied.

ISSN:0003-2719    

DOI:10.1080/00032718108055494

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Low energy (0–100 eV acceleration tandem quadrapole technique) and high energy (CID-MIKES technique) collision induced decomposition methods are compared, using selected methyl ketones. The compounds studied were acetone, 2-butanone, cyclopropyl methyl ketone, and 3-methyl-2-pentanone.

ISSN:0003-2719    

DOI:10.1080/00032718108055495

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Correlations between extraction distribution ratios, bond types, and common solvent physical properties were determined for 19 extraction systems. Different types of bonding are involved in the water adduct formation on different types of chelates.

ISSN:0003-2719    

DOI:10.1080/00032718108055496

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

ISSN:0003-2719    

DOI:10.1080/00032718108055487

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor