Volatile organic analysis by direct aqueous injection

Pyle, Steven M.; Gurka, Donald F.

doi:10.1016/0039-9140(94)00126-x

Cited by 19 publications

(10 citation statements)

References 7 publications

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“…Conventional liquid-liquid extraction (LLE) [16][17][18][19], purge and trap [20][21][22][23][24], direct aqueous injection (DAI) [25][26][27], static headspace (HS) [28][29][30], solid-phase microextraction (SPME) [31,32], solid-phase extraction [33], headspace solid-phase microextraction (HS-SPME) [34][35][36][37], liquid-phase microextraction (LPME) [38,39], headspace-liquid-phase microextraction (HS-LPME) [40,41], hollow fiber membrane (HF-LPME) [42,43] and dispersive liquid-liquid microextraction (DLLME) [44,45], have been used to monitor regulated THMs species in drinking water.…”

Section: Introductionmentioning

confidence: 99%

Application of hollow fiber liquid phase microextraction for simultaneous determination of regulated and emerging iodinated trihalomethanes in drinking water

Domínguez-Tello

Arias-Borrego

García-Barrera

et al. 2015

Journal of Chromatography A

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Section: Introductionmentioning

confidence: 99%

Application of hollow fiber liquid phase microextraction for simultaneous determination of regulated and emerging iodinated trihalomethanes in drinking water

Domínguez-Tello

Arias-Borrego

García-Barrera

et al. 2015

Journal of Chromatography A

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“…The most commonly used SPME fiber for the analysis of regulated THMs is the carboxen/polydimethylsiloxane (CAR/PDMS) [16][17][18]. Several methods have been reported in the literature for the quantification of regulated THMs [14,[21][22][23][24], with the majority employing gas chromatography (GC) with either electron capture detection (ECD) or mass spectrometry (MS). Recently, Charrois (2011) reviewed DBPs analytical methods including I-THMs [25].…”

Section: Introductionmentioning

confidence: 99%

Simultaneous analysis of 10 trihalomethanes at nanogram per liter levels in water using solid-phase microextraction and gas chromatography mass-spectrometry

Allard

Charrois

Joll

et al. 2012

Journal of Chromatography A

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Trihalomethanes are predominantly formed during disinfection of water via reactions of the oxidant with natural organic matter. Even though chlorinated and brominated trihalomethanes are the most widespread organic contaminants in drinking water, when iodide is present in raw water iodinated trihalomethanes can also be formed. The formation of iodinated trihalomethanes can lead to taste and odor problems and is a potential health concern since they have been reported to be more toxic than their brominated or chlorinated analogs. Currently, there is no published standard analytical method for I-THMs in water. The analysis of 10 trihalomethanes in water samples in a single run is challenging because the iodinated trihalomethanes are found at very low concentrations (ng/L range), while the regulated chlorinated and brominated trihalomethanes are present at much higher concentrations (above μg/L). An automated headspace solid-phase microextraction technique, with a programmed temperature vaporizer inlet coupled with gas chromatography-mass spectrometry, was developed for routine analysis of 10 trihalomethanes i.e. bromo-, chloro- and iodo-trihalomethanes in water samples. The carboxen/polydimethylsiloxane/divinylbenzene fiber was found to be the most suitable. The optimization, linearity range, accuracy and precision of the method are discussed. The limits of detection range from 1 ng/L to 20 ng/L for iodoform and chloroform, respectively. Matrix effects in treated groundwater, surfacewater, seawater, and secondary wastewater were investigated and it was shown that the method is suitable for the analysis of trace levels of iodinated trihalomethanes in a wide range of waters. The method developed in the present study has the advantage of being rapid, simple and sensitive. A survey conducted throughout various process stages in an advanced water recycling plant showed the presence of iodinated trihalomethanes at ng/L levels.

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“…Grob has described in depth the different parameters that affect this mode of injection for aqueous samples. 31 Basing their work on his development, many workers have used the DAI technique for rapid screening of THMs alone 20,45 or with other halogenated organics 24,46 in drinking water.…”

Section: Direct Aqueous Injection Gas Chromatographymentioning

confidence: 99%

“…As a compromise, film thicknesses of 2 -5 µm have generally been used for the analysis of THMs by DAI. 20,22,24,45,46 The stationary phase should be immobilized through crosslinking and chemical bonding to the column wall to avoid its hydrolysis by the large amount of water injected. Medium-and wide-bore columns (0.28 -0.54 mm) are typical, since the injection of a large volume of water could block temporarily the gas flow in a small diameter column.…”

Section: Instrumentationmentioning

confidence: 99%

Trihalomethanes in Water, Analysis of

Lépine

Gilbert

2000

Encyclopedia of Analytical Chemistry

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Trihalomethanes (THMs) are considered to be the major by‐products found in water after the chlorination process. They mainly consist of chloroform (CHCl 3 ), bromodichloromethane (CHBrCl 2 ), dibromochloromethane (CHBr 2 Cl) and bromoform (CHBr 3 ). Their content in drinking water is regulated and the maximum contaminant level (MCL) of 100 µg L −1 established in 1979 by the United States Environmental Protection Agency (USEPA) for total THMs, based on a running annual average, still prevails and has been adopted in many other countries. In this article, we describe the four major analytical techniques routinely used for THM analysis. All of these analytical techniques use gas chromatography (GC) with a halogen‐specific detector such as the electron capture detector (ECD), electrolyte conductivity detector (ELCD) or mass spectrometry (MS). With high‐efficiency capillary columns now commonly available and the high sensitivity of the ECD, all these techniques have detection limits (DLs) at or below 0.1 µg L −1 for each of the four THMs, which is more than adequate for drinking water or beverage applications. The four analytical approaches differ by the way the THMs are introduced into the chromatographic column. Direct aqueous injection (DAI), where the sample is directly injected into the GC column, is fast and simple. It does not require any other piece of equipment than the gas chromatograph itself. However, since everything in the sample is injected in the column, it is limited to relatively clean matrices. It is generally used as a screening technique when a limited number of samples are analyzed. The second method uses liquid–liquid extraction (LLE) of the THMs with an organic solvent, usually pentane, which is then injected into the GC column. The extraction step offers the possibility of concentrating the THMs from a large‐volume sample and isolates them from inorganic salts. However, LLE is by far the most time‐consuming procedure and is not well suited for routine analysis of a large number of samples. The last two methods take advantage of the high volatility of the THMs to isolate and concentrate them in the gas phase. In the headspace (HS) technique, the aqueous sample is heated in a sealed vial and an equilibrium is reached between the THMs present in the water and the HS above, from which an aliquot is injected into the GC column. It is simple to use and easily automated. The sensitivity is limited by the partition coefficient of each species between the liquid and gas phases and the size of the gas aliquot injected into the GC column. The DL has been decreased to 1 ng L −1 by use of a long transfer time to the gas chromatograph and cryogenic trapping in the very first portion of the GC column. Finally, in the purge‐and‐trap (PT) technique, the THMs are purged out of the sample by an inert gas and concentrated on a solid sorbent, thermally desorbed and injected into the GC column. With a purge efficiency close to 100% for these volatile compounds, all the molecules present in a relatively large water sample (typically 5–25 mL) are injected into the GC column. It is the most sensitive of the four analytical methods and a DL below the 1 ng L −1 level has been achieved with cryogenic focusing at the column head.

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Volatile organic analysis by direct aqueous injection

Cited by 19 publications

References 7 publications

Application of hollow fiber liquid phase microextraction for simultaneous determination of regulated and emerging iodinated trihalomethanes in drinking water

Application of hollow fiber liquid phase microextraction for simultaneous determination of regulated and emerging iodinated trihalomethanes in drinking water

Simultaneous analysis of 10 trihalomethanes at nanogram per liter levels in water using solid-phase microextraction and gas chromatography mass-spectrometry

Trihalomethanes in Water, Analysis of

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