Improvement of the purge‐ and ‐trap technique for the rapid analysis of volatile organic pollutants in water

Mehran, Mahrzad F.; Nickelsen, Michael G.; Golkar, N.; Cooper, William J.

doi:10.1002/jhrc.1240130611

Cited by 24 publications

(2 citation statements)

References 7 publications

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“…All samples were collected, covered with an airtight cap and kept in the refrigerator at 4°C temperature before analyzed. MTBE concentration was measured using Gas Chromatography (GC) device made by the Agilent company equipped with the Flame Ionization Detector (FID) according to the U.S EPA502.2 test method for analysis of MTBE in the liquid phase through GC with the purge and trap device (Mehran et al 1990). The absorption column of HP-5 with a length of 30 m and inner diameter of 0.32 mm was used A temperature program of the column was as follows: initial temperature of the column was 35°C and after 4 minutes, at the rate of 10°C per minute up to the 150°C and with reaching to this temperature, the method was nished.…”

Section: Analysesmentioning

confidence: 99%

WITHDRAWN: Removal of MTBE From Groundwater Using A PRB of ZVI/Sand Mixtures: Role of Nitrate And Hardness

Ghayurdoost

Assadi

Mehrasbi

2021

Preprint

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In this study, the efficiency of the permeable reactive barrier (PRB) in a column reactor using zero-valent iron (ZVI) particles and sand mixture in the removal of methyl tert-butyl ether (MTBE) from aquatic phases was investigated. The main operating parameters influence reactor performance such as pH, reaction time, pollutant content, catalyst load, hydraulic loading rate, and the reaction rate constant was evaluated. The results showed that the efficiency of process decreased with increasing pH, inflow, and pollutant concentration. In this case, the optimal conditions were obtained at pH=7, flow rate=0.23 m3/m2.d and C0=1 mg/L, which achieved a remarkable removal efficiency up to 90.32%. The being of high nitrate and hardness concentrations as intervening factors were led to reduce process efficiency to less than 44.61% and 51.4%, respectively. Lack of interfering factors had a considerable effect on the reaction rate of MTBE reduction that is approximately 2.65 and 4.11 times higher than in the presence of calcium hardness and nitrate, respectively. The PRB can be operated to remediate groundwater containing hydrocarbons based on filling media and hydraulic conditions.

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Section: Analysesmentioning

confidence: 99%

WITHDRAWN: Removal of MTBE From Groundwater Using A PRB of ZVI/Sand Mixtures: Role of Nitrate And Hardness

Ghayurdoost

Assadi

Mehrasbi

2021

Preprint

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“…Use of a commercially available purge-and-trap apparatus will solve this problem. Method detection limits for benzene have been reported as low as 0.006 ppb [30 pg benzene in 5 ml water; (4)]. The purge-and-trap apparatus has recently been acquired in our laboratory; experiments using this instrument suggest these limits will be attainable.…”

Section: Discussionmentioning

confidence: 99%

S-Phenylcysteine in Albumin as a Benzene Biomarker

Bechtold¹,

Strunk²

1996

Environmental Health Perspectives

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Biological markers of internal dose are useful for improving the extrapolation of health effects from exposures to high levels of toxic air pollutants in animals to low, ambient exposures in humans. Previous results from our laboratory have shown that benzene is metabolized by humans to form the adduct S-phenylcysteine (SPC). Levels of SPC measured in humans occupationally exposed to benzene were increased linearly relative to exposure concentrations ranging from 0 to 23.1 ppm for 8 hr/day, 5 days/week. However, the method of measurement used was laborious, prone to imprecision and interferences, and insufficiently sensitive for the low-dose exposures anticipated in the United States (100 ppb >). An improved chemical method was necessary before SPC adducts in albumin could be used as a benzene biomarker. A simple, sensitive method to measure SPC adducts is being developed and is based on the cleavage of the cysteine sulfhydryl from blood proteins treated with Raney nickel (RN) in deuterium oxide. The product of the reaction with SPC is monodeuterobenzene. SPC treated with RN released monodeuterobenzene in a concentration-dependent fashion. SPC was measured by RN treatment of globin from rats repeatedly exposed by inhalation to 600 ppm benzene. SPC levels measured using the RN approach were 690 +/- 390 pmol SPC/mg Hb (mean +/- % difference, n = 2), as opposed to 290 +/- 45 pmol SPC/mg Hb (mean +/- SEM, n = 3) as measured by our previous method. This method may facilitate the cost-effective, routine analysis of SPC in large populations of people exposed to ambient levels of benzene.

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Performance evaluation of a surface acoustic wave analyzer to measure vocs in air and water

2003

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The performance of a fast gas chromatograph equipped with a Surfdce Acoustic Wave (SAW) detector i s evaluated in this p a p . Tbe instrument was developed for the rapld analysis of volatile oqanic compounds in air or water. Tbe SAWdetectol; the fist and only known integrating detector forgas chromatographs (GG), operates by responding to the muss of material exiting the GC column. Material adhering to the SAWsurface changes its operating frequency, which & detected by the system electronics and converted into a chromatogram. The system requires no high voltages or radioactive ionization sources, and is compact andportable. The millisecond response of the detector allows high speed analysis-measured in seconds-to takeplace. Thepformance of the GUSAWsystem is comparable to laboratory GCs in terms of limit of detection, precision, accuracy, and interference while screening environments in essentially real time (10 seconds). The results of the instrument evaluation for 10 common organic compounds in air and water matrices arepresented. INTROWCTlONUsing portable instruments to analyze semi-volatile and volatile organic compounds (VOCs) is gaining popularity for use in field applications [ll. Accurate, high speed measurements performed in the field can substantially reduce the cost of analysis. For VOCs, a number of field screening instruments, such as Gas Chromatographs (GCs), have emerged. But, there is still a lack of instruments versatile enough to analyze a wide range of organic compounds. GCs are an effective tool, but their usefulness as a field tool can be limited by retention times of several minutes, or even more for relatively simple separations. Because there is frequently no pre-concentration of the sample, the limits of detection (LOD) and quantitation (LOQ) may not be adequate for many applications 12, 31.Ongoing research has shown that GC analysis speed can be significantly improved 14-61, and that detection of organics and inorganics can be enhanced with the use of a Surface Acoustic Wave (SAW) sensor I7, 81. Until recently, however, no major breakthroughs in GC design had resulted in sub-minute analysis of VOCs [9, 101. This paper details the development and application of a novel field portable GC system equipped with a SAW detector. Performance results are given for a SAW analyzer that was subjected to a number of tests in the laboratory and field surroundings. These test results show that it is possible to speciate and quantlfy a wide range of environmental pollutants in near real time (less than 10 seconds) with good precision and accuracy. TECHNOLOGY DESCRIPTIONElectronic Sensor Technology (EST) has developed the model 7100 Fast GC to meet the needs of a field portable gas chromatograph [lll. The 7100, shown in Figure 1, is a high speed GC that utilizes a new type of detector based upon SAW sensor technology. This novel detector, coupled with proprietary GC technology, enables chromatographic measurements of soil, water, and air to be performed in less than 10 seconds, The SAW sensor and fast...

show abstract

Improvement of the purge‐ and ‐trap technique for the rapid analysis of volatile organic pollutants in water

Cited by 24 publications

References 7 publications

WITHDRAWN: Removal of MTBE From Groundwater Using A PRB of ZVI/Sand Mixtures: Role of Nitrate And Hardness

WITHDRAWN: Removal of MTBE From Groundwater Using A PRB of ZVI/Sand Mixtures: Role of Nitrate And Hardness

S-Phenylcysteine in Albumin as a Benzene Biomarker

Performance evaluation of a surface acoustic wave analyzer to measure vocs in air and water

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