Generation of standard gaseous mixtures

́nik, Jacek Namies

doi:10.1016/s0021-9673(01)87581-6

Cited by 131 publications

(46 citation statements)

References 173 publications

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“…Static methods rely on mixtures of gases in closed containers of known volume, while dynamic processes involve mixing a continuous flow of analyte into a dilution or carrier stream. A comprehensive review of standard generation processes for VOC can be found elsewhere (Barratt, 1981;Namiesnik, 1984;Naganowska-Nowak et al, 2005) Modern static techniques most commonly utilize mixtures of gases in treated high-pressure cylinders (Apel et al, 1998;Rappengluck et al, 2006;Apel et al, 1994). Static techniques are the preferred calibration method for many field and laboratory investigations due to the portability and robust nature of high-pressure gas cylinders.…”

Section: Introductionmentioning

confidence: 99%

Development and validation of a portable gas phase standard generation and calibration system for volatile organic compounds

et al. 2010

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Abstract. We report on the development of an accurate, portable, dynamic calibration system for volatile organic compounds (VOCs). The Mobile Organic Carbon Calibration System (MOCCS) combines the production of gas-phase VOC standards using permeation or diffusion sources with quantitative total organic carbon (TOC) conversion on a palladium surface to CO 2 in the presence of oxygen, and the subsequent CO 2 measurement. MOCCS was validated using three different comparisons: (1) TOC of high accuracy methane standards compared well to expected concentrations (3% relative error), (2) a gas-phase benzene standard was generated using a permeation source and measured by TOC and gas chromatography mass spectrometry (GC-MS) with excellent agreement (<4% relative difference), and (3) total carbon measurement of 4 known gas phase mixtures were performed and compared to a calculated carbon content to agreement within the stated uncertainties of the standards. Measurements from laboratory biomass burning experiments of formic acid by negative-ion proton-transfer chemical-ionization mass spectrometry (NI-PT-CIMS) and formaldehyde by proton transfer reaction-mass spectrometry (PTR-MS), both calibrated using MOCCS, were compared to open path Fourier transform infrared spectroscopy (OP-FTIR) to validate the MOCCS calibration and were found to compare well (R 2 of 0.91 and 0.99, respectively).

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Section: Introductionmentioning

confidence: 99%

Development and validation of a portable gas phase standard generation and calibration system for volatile organic compounds

et al. 2010

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“…The instrument utilizes the purge and trap principle [1± 5], which is particularly suitable for the isolation of volatile chloro-organic compounds from water [3,6,7], and, hence, operates in a periodic mode. It was decided to utilize not the total stripping but rather a dynamic one, when the liquid sample and the stripping gas, both at constant¯ow rates, come into contact with each other in a countercurrent purging bubbler, where the volatile chloro-organic compounds are divided between the two phases with their respective partition coeae cients [6] kept constant by maintaining the temperature at 25 § 2 8C.…”

Section: Operating Principlementioning

confidence: 99%

Automated analyser for monitoring trace amounts of volatile chloro-organic compounds in recirculated industrial water

Janicki¹,

Chrzanowski²,

Wasik³

et al. 2002

Journal of Automated Methods & Management in Chemistry

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An automated analyser of volatile chloro-organic compounds in water was constructed and tested using standard mixtures of dichloromethane and dichloroethane. It was based on continuous, countercurrent gas stripping of the liquid sample followed by periodic trapping of the analytes on two traps alternately connected to the bubbler outlet, and thermal desorption. When one trap performed adsorption, the other underwent desorption and cooling. Analytes were detected by an ECD detector. Integration, calibration, calculations and overall operating cycle control was performed by a microcomputer. The instrument guarantees a 0.02 ppm Cl (w/w) detection limit, a 0º2 ppm detection range and 2 months of autonomous operation. Results are reported every 13 min.

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“…This is achieved by designing analytical methods in a way that reduces or eliminates hazardous substances that are used in or generated by the method to be more benign to the environment , however, most of the used HPLC methods do not consider the impact of application of green methods. Namies´nik presented examples of the application of green chemistry in the analytical laboratory. An environmentally friendly approach compatible with conventional HPLC equipment and columns was described for the development of separation methods for fingerprinting complex matrices .…”

Section: Introductionmentioning

confidence: 99%

Validated green high‐performance liquid chromatographic methods for the determination of coformulated pharmaceuticals: A comparison with reported conventional methods

Elzanfaly

Hegazy

Saad

et al. 2015

J of Separation Science

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The introduction of sustainable development concepts to analytical laboratories has recently gained interest, however, most conventional high-performance liquid chromatography methods do not consider either the effect of the used chemicals or the amount of produced waste on the environment. The aim of this work was to prove that conventional methods can be replaced by greener ones with the same analytical parameters. The suggested methods were designed so that they neither use nor produce harmful chemicals and produce minimum waste to be used in routine analysis without harming the environment. This was achieved by using green mobile phases and short run times. Four mixtures were chosen as models for this study; clidinium bromide/chlordiazepoxide hydrochloride, phenobarbitone/pipenzolate bromide, mebeverine hydrochloride/sulpiride, and chlorphenoxamine hydrochloride/caffeine/8-chlorotheophylline either in their bulk powder or in their dosage forms. The methods were validated with respect to linearity, precision, accuracy, system suitability, and robustness. The developed methods were compared to the reported conventional high-performance liquid chromatography methods regarding their greenness profile. The suggested methods were found to be greener and more time- and solvent-saving than the reported ones; hence they can be used for routine analysis of the studied mixtures without harming the environment.

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Generation of standard gaseous mixtures

Cited by 131 publications

References 173 publications

Development and validation of a portable gas phase standard generation and calibration system for volatile organic compounds

Development and validation of a portable gas phase standard generation and calibration system for volatile organic compounds

Automated analyser for monitoring trace amounts of volatile chloro-organic compounds in recirculated industrial water

Validated green high‐performance liquid chromatographic methods for the determination of coformulated pharmaceuticals: A comparison with reported conventional methods

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