scholarly journals Progressive Cellular Architecture in Microscale Gas Chromatography for Broad Chemical Analyses

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3089
Author(s):  
Weilin Liao ◽  
Xiangyu Zhao ◽  
Hsueh-Tsung Lu ◽  
Tsenguun Byambadorj ◽  
Yutao Qin ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Homeland Security ◽  
Single Chip ◽  
Molecular Weight Range ◽  
Column Temperature ◽  
Cellular Architecture ◽  
Flame Ionization ◽  
Separation Column ◽  
Wide Range ◽  
Separation Columns

Gas chromatography is widely used to identify and quantify volatile organic compounds for applications ranging from environmental monitoring to homeland security. We investigate a new architecture for microfabricated gas chromatography systems that can significantly improve the range, speed, and efficiency of such systems. By using a cellular approach, it performs a partial separation of analytes even as the sampling is being performed. The subsequent separation step is then rapidly performed within each cell. The cells, each of which contains a preconcentrator and separation column, are arranged in progression of retentiveness. While accommodating a wide range of analytes, this progressive cellular architecture (PCA) also provides a pathway to improving energy efficiency and lifetime by reducing the need for heating the separation columns. As a proof of concept, a three-cell subsystem (PCA3mv) has been built; it incorporates a number of microfabricated components, including preconcentrators, separation columns, valves, connectors, and a carrier gas filter. The preconcentrator and separation column of each cell are monolithically implemented as a single chip that has a footprint of 1.8 × 5.2 cm2. This subsystem also incorporates two manifold arrays of microfabricated valves, each of which has a footprint of 1.3 × 1.4 cm2. Operated together with a commercial flame ionization detector, the subsystem has been tested against polar and nonpolar analytes (including alkanes, alcohols, aromatics, and phosphonate esters) over a molecular weight range of 32–212 g/mol and a vapor pressure range of 0.005–231 mmHg. The separations require an average column temperature of 63–68 °C within a duration of 12 min, and provide separation resolutions >2 for any two homologues that differ by one methyl group.

scholarly journals Methodology development for routine estimation of chlorpropham in commercial potato stores

2012 ◽  
Vol 30 (No. 1) ◽  
pp. 67-73 ◽  
Author(s):  
W.A. Khan ◽  
H.J. Duncan ◽  
A.K. Baloch ◽  
G. McGowan
Keyword(s):  
Gas Chromatography ◽  
Analysis Of Variance ◽  
Potato Tubers ◽  
Ionization Detector ◽  
Methodology Development ◽  
Analytical Technique ◽  
Flame Ionization ◽  
Commercial Potato ◽  
Wide Range ◽  
Complex Structural

Chlorpropham is employed worldwide as an anti-sprout chemical to the harvested potato tubers during storage. A simple and precise analytical technique is developed for routine estimation of the sprout suppressant from a large number of potato samples supplied from commercial stores demanding quick analysis. Chlorpropham is extracted completely from potato tubers by intelligent reflux extraction followed by quantification using GC-FID (Gas Chromatography-Flame Ionization Detector) equipment. In this article, the performance of the technique is compared with the lengthy extraction/cleanup process, and the results are validated as per one-way analysis of variance. The recommended technique is found to offer rapid, accurate, and reliable analytical results with ease in handling a large number of samples constituting a wide range of residual chlorpropham levels often found in a complex structural commercial potato stores.  

scholarly journals A new approach for measuring the carbon and oxygen content of atmospherically relevant compounds and mixtures

2020 ◽  
Vol 13 (9) ◽  
pp. 4911-4925
Author(s):  
James F. Hurley ◽  
Nathan M. Kreisberg ◽  
Braden Stump ◽  
Chenyang Bi ◽  
Purushottam Kumar ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Particulate Matter ◽  
Organic Carbon ◽  
Oxygen Content ◽  
Flame Ionization Detector ◽  
Ionization Detector ◽  
New Approach ◽  
Flame Ionization ◽  
Wide Range ◽  
Moderate Cost

Abstract. Due to its complexity, gas- and particle-phase organic carbon in the atmosphere is often classified by its bulk physicochemical properties. However, there is a dearth of robust, moderate-cost approaches to measure the bulk chemical composition of organic carbon in the atmosphere. This is particularly true for the degree of oxygenation, which critically affects the properties and impacts of organic carbon but for which routine measurement approaches are lacking. This gap has limited the understanding of a wide range of atmospheric components, including particulate matter, the mass of which is monitored worldwide due to its health and environmental effects but the chemical characterization of which requires relatively high capital costs and complex operation by highly trained technical personnel. In this work, we demonstrate a new approach to estimate the mass of carbon and oxygen in analytes and mixtures that relies only on robust, moderate-cost detectors designed for use with gas chromatography. Organic compounds entering a flame ionization detector were found to be converted with approximately complete efficiency to CO2, which was analyzed downstream using an infrared detector to measure the mass of carbon analyzed. The ratio of the flame ionization detector (FID) signal generated to CO2 formed (FID∕CO2) was shown to be strongly correlated (R2=0.89) to the oxygen-to-carbon ratio (O∕C) of the analyte. Furthermore, simple mixtures of analytes behaved as the weighted average of their components, indicating that this correlation extends to mixtures. These properties were also observed to correlate well with the sensitivity of the FID estimated by structure activity relationships (quantified as the relative effective carbon number). The relationships between measured FID∕CO2, analyte O∕C, and FID sensitivity allow the estimation of one property from another with <15 % error for mixtures and <20 % error for most individual analytes. The approach opens the possibility of field-deployable, autonomous measurement of the carbon and oxygen content of particulate matter using time-tested, low-maintenance detectors, though such an application would require some additional testing on complex mixtures. With some instrumental modifications, similar measurements on gas-phase species may be feasible. Moreover, the potential expansion to additional gas chromatography detectors may provide concurrent measurement of other elements (e.g., sulfur, nitrogen).

Multiresidue Method for Determination of Pesticides in Kiwif ruit, Apples, and Berryfruits

1983 ◽  
Vol 66 (4) ◽  
pp. 1003-1008
Author(s):  
P T Holland ◽  
T K Mcghie
Keyword(s):  
Gas Chromatography ◽  
Water Soluble ◽  
Electron Capture Detection ◽  
Synthetic Pyrethroids ◽  
Photometric Detection ◽  
Flame Ionization ◽  
Organochlorine Insecticides ◽  
Routine Surveillance ◽  
Wide Range

Abstract A rapid multiresidue procedure for fruits, based on methanol extraction, is presented. Water and highly water-soluble co-extractives are removed by partitioning the pesticides into toluene. Carbon-cellulose-Florisil cleanup is performed before gas chromatography on OV-225 with electron capture detection. A wide range of pesticides can be determined to 0.1 mg/kg without concentrating the extract. Gas chromatography of the crude toluene partition using SE-30 and an alkali flame ionization detector provides confirmatory data and allows detection of some carbamates. Dichlorvos, dimethoate, and acephate are determined directly in the methanol extract by flame photometric detection. High recoveries were obtained for 4 organochlorine insecticides, 13 organophosphorus insecticides, 2 synthetic pyrethroids, two JV-methyl carbamates, and 10 fungicides. The method is economical of solvents, glassware, and time, and is recommended for routine surveillance of residue levels on fruit.

scholarly journals Quantification of Selected Vapour-Phase Compounds using Thermal Desorption-Gas Chromatography

2004 ◽  
Vol 21 (4) ◽  
pp. 211-215
Author(s):  
DWJ McLaughlin ◽  
RE Bell ◽  
DJ Graham ◽  
R McKeivor
Keyword(s):  
Gas Chromatography ◽  
Thermal Desorption ◽  
Vapour Phase ◽  
Ionization Detector ◽  
University Of Kentucky ◽  
Validation Data ◽  
Flame Ionization ◽  
Wide Range ◽  
The University ◽  
Good Agreement

AbstractA robust method for the analysis of selected vapour phase (VP) compounds in mainstream smoke (MSS) is described. Cigarettes are smoked on a rotary smoking machine and the VP that passes through the Cambridge filter pad collected in a TedlarA¯ bag. On completion of smoking, the bag contents are sampled onto an adsorption tube containing a mixed carbon bed. The tube is subsequently analysed on an automated thermal desorption (TD) system coupled to a gas chromatography-flame ionization detector (GC-FID) using a PoraPLOT-Q column. Quantification of 14 volatile compounds including the major carbonyls is achieved. Details of the method validation data are included in this paper. This method has been used to analyse the VP of cigarette MSS over a wide range of ‘tar’ deliveries and configurations with excellent repeatability. Results for the University of Kentucky reference cigarette 1R4F are in good agreement with reported values.

Establishment of Gas Chromatography Analytical Method for 4-Amino-2-Methylpentane

2017 ◽  
Vol 865 ◽  
pp. 624-629
Author(s):  
Shu Chun Zhao ◽  
Yan Yan Yan ◽  
Yue Zhang ◽  
Xin Rui Dong ◽  
Hua Zhao ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Flow Rate ◽  
Gas Flow ◽  
Gas Flow Rate ◽  
Pure Nitrogen ◽  
Column Temperature ◽  
Carrier Gas ◽  
Flame Ionization ◽  
Split Ratio ◽  
Accuracy And Precision

The aim of this paper was to establish a gas chromatography (GC) method for the determination of 4-amino-2-methylpentane and validate the methodology. The gas chromatography conditions such as column temperature, carrier gas flow rate, split ratio and the make-up gas flow rate were investigated in detail. The chromatographic column used in this method was capillary column of DA-1. The oven temperature was initially held at 40 °C for 15 min and was then programmed temperature to 140 °C at the rate of 75 °C/min and held for 10 min. The injection temperature was 180 °C and the flame ionization detector temperature was 200 °C. The carrier gas was high pure nitrogen with a flow rate of 0.8 mL/min. The split ratio was 130:1 and the make-up gas flow rate was 30 mL/min. Good linearity of 4-amino-2-methylpentane was obtained within the concentration range of 25.44 mg/mL to 84.81 mg/mL and the correlation coefficient was 0.9990. Good accuracy and precision were obtained and the average recovery was 101.76%. The quantification limit of 4-amino-2-methylpentane was 7.21 μg/mL and the detection limit of that was 3.72 μg/mL. The method was well-validated and proved to be used for quality test of 4-amino-2-methylpentane.

scholarly journals Sensitive determination of impurities in samples of vodka by gas chromatography with flame-ionization detection

2015 ◽  
pp. 3
Author(s):  
Nassiba Baimatova ◽  
Olga Demyanenko ◽  
Ahmad Zia
Keyword(s):  
Gas Chromatography ◽  
Direct Analysis ◽  
Alcoholic Beverages ◽  
Inlet Temperature ◽  
Flame Ionization Detection ◽  
Negative Consequences ◽  
Ionization Detection ◽  
Flame Ionization ◽  
Wide Range

<p>Vodka is one of the most popular alcoholic drinks around the world. Adulteration of vodkas lead to many negative consequences. A number of analytical methods covers a wide range of analytes and allows detection of adulterated alcoholic beverages, however, most of these methods are very labor and time consuming or require expensive analytical instrumentation. The simplest and thus most popular method is based on direct analysis by gas chromatography (GC) with flame-ionization detection (FID). The main drawback of this method for discovery of adulterated vodka samples is insufficient sensitivity. The aim of this study was to increase sensitivity of the method for determination of key vodka impurities. Optimized parameters included split ratio 10:1, inlet temperature &gt;120 °C, initial oven temperature 60 °C, flow rates of make-up gas, air and hydrogen 50, 400 and 40 mL/min, respectively. Obtained calibration plots are linear in the concentration range between 1 and 1000 mg/L with approximation coefficients R<sup>2</sup>&gt;0.99. Compared to a standard method, slope factors are about 4 times higher when optimized method is used proving its higher sensitivity.</p>

Analysis of Aromatic Amines in Industrial Wastewater by Capillary Gas Chromatography-Mass Spectrometry

2000 ◽  
Vol 35 (2) ◽  
pp. 245-262 ◽  
Author(s):  
Francis I. Onuska ◽  
Ken A. Terry ◽  
R. James Maguire
Keyword(s):  
Gas Chromatography ◽  
Aromatic Amines ◽  
Methylene Chloride ◽  
Solid Phase ◽  
Stationary Phases ◽  
Gas Chromatography Mass Spectrometry ◽  
Substituted Anilines ◽  
Environmental Media ◽  
Solid Phase Extraction Cartridge ◽  
Wide Range

Abstract The analysis of aromatic amines, particularly benzidines, at trace levels in environmental media has been difficult because of the lack of suitable deactivated capillary column stationary phases for gas chromatography. This report describes the use of an improved type of column as well as a method for the analysis of anilines and benzidines in water, wastewater and sewage samples. Extraction procedures are applicable to a wide range of compounds that are effectively partitioned from an aqueous matrix into methylene chloride, or onto a solid-phase extraction cartridge. The extracted analytes are also amenable to separation on a capillary gas chromatographic column and transferable to the mass spectrometer. These contaminants are converted to their N-trifluoroacetyl derivatives. Aniline and some substituted anilines, and 3,3’-dichlorobenzidine and benzidine were determined in 24-h composite industrial water, wastewater, primary sludge and final effluent samples at concentrations from 0.03 up to 2760 µg/L.

Flame ionization detector response to coeluting hydrocarbons and carbon disulphide and its application to the determination of the sum of C6-C11 alkanes and cycloalkanes in air

1983 ◽  
Vol 48 (3) ◽  
pp. 722-734
Author(s):  
Martin Koval
Keyword(s):  
Carbon Disulphide ◽  
Internal Standard ◽  
Calibration Procedure ◽  
Detector Response ◽  
Column Temperature ◽  
Flame Ionization ◽  
Other Substances ◽  
Flame Ionisation Detector ◽  
Ionisation Detector

The flame ionisation detector response to C6-C11 aliphatic hydrocarbon solutions in carbon disulphide in the concentration range between 1.3-9.5 mg ml-1 retained lineary despite the excess of solvent entering the detector simultaneously with the analyte. Pure carbon disulphide exhibited a small positive detector response which did not interfere in calibration procedure and which, under certain GC conditions, inverted to negative values. This response was not proportional to the injected volume and was strongly influenced by the column temperature and/or bleed. On the basis of these findings, a method compatible with the widely used charcoal tube carbon disulphide desorption procedure was developed and evaluated. It consists of static desorption of the sum of aliphatic alkanes and cycloalkanes from the activated charcoal after which an internal standard is added to the supernatant eluate. The resulting carbon disulphide solution is analysed on a highly polar stationary phase 1,2,3-tris(2-cyanoethoxy)propane where the solvent and the analyte coelute in a single peak, the height of which is practically proportional to the sum of alkanes and cycloalkanes present. This also makes determinations of other substances present in the sample more simple. The field test of the proposed method yielded values comparable in precision and accuracy with a control infrared spectrophotometric method.

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