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1.
Optimization of the coupling of high-temperature liquid chromatography and flame ionization detection application to the separations of alcohols 总被引:2,自引:0,他引:2
Guillarme D Heinisch S Gauvrit JY Lanteri P Rocca JL 《Journal of chromatography. A》2005,1078(1-2):22-27
The feasibility of coupling high-temperature liquid chromatography (HTLC) to flame ionization detection (FID) has been studied. FID parameter values (hydrogen flow-rate, air flow-rate and FID temperature), typically set in gas chromatography are rarely suitable for liquid chromatography. Best values depend obviously on the water flow rate which is defined depending on both column temperature and column internal diameter. The FID parameters were optimized according to the water flow-rate by means of an experimental design. The potential of the method is shown with some alcohol separations and the value of increasing column temperature while reducing the column diameter is highlighted. 相似文献
2.
Formaldehyde, water, methanol, butanal, and butanone are characterized by gas chromatography using three pulsed-discharge photoionization detectors (PDPIDs) and a flame ionization detector (FID). One of the PDPIDs is operated in helium mode, and the other two are operated in argon and krypton modes. The FID is included for comparison. The PDPIDs are used to efficiently differentiate between and quantitatively identify formaldehyde and the other three compounds in a sample mixture. This is accomplished by using butanone as the internal standard and correlating the relative responses of the four organic compounds in the helium-, argon-, and krypton-mode PDPIDs with their relative retention times. 相似文献
3.
A passive method with membrane permeation sampling for the determination of time-weighted-average (TWA) concentration of formaldehyde in air is described. The sampling device was constructed by affixing an unbacked dimethyl silicone membrane to the base of a glass tube and by sealing the top with a rubber stopper. Formaldehyde permeates the membrane and reacts with 2-(hydroxymethyl)piperidine (2-HMP) coated on the surface of XAD-2. Sampling times from 15 min to 8 hr have been used. The formaldehyde—oxazolidine produced is thermally desorbed and determined by a packed column gas chromatograph equipped with a flame ionization detector (FID). The response of the monitor is directly proportional to the external concentration of formaldehyde over the concentration range 0.050–100 ppm. The permeation constant (the slope of the permeation curve) of the membrane is 0.333 μg ppm−1. hr, and the detection limit of the method is 0.03 ppm for an 8-hr sampling period. Relative humidity (RH) (35–94%), temperature (0–82°) and storage period (0–25 days) do not affect the permeation process for sample collection. Moreover, potential chemical interferences, 10 ppm acetone or acrolein, respectively, have no detectable effect on the process. The method gives TWA concentration directly from the measurements, and the equipment is economical and convenient for personal or multi-location sample collections. 相似文献
4.
The sensitivity of a MEMS μFID with reduced fuel gas consumption for portable applications like mobile GC or THA is examined. It is shown that sensitivity depends on flame size and type of sample gas supply (either separate supply or premixed with the hydroxygen). In contrast to conventional FIDs, the sensitivity of the μFID increases with decreasing molecule size. The sensitivity to methane can be optimized up to conventional values. Measurements with the μFID as a second detector in a μGC module prove the additional functionality of such a system. 相似文献
5.
We present the results of a study of percent composition for a mixture which has been separated by gas chromatography and analyzed using helium pulsed-discharge photoionization detection (He-PDPID) and flame ionization detection (FID). FID has long been the means by which the percent composition of a hydrocarbon mixture has been determined since it has been previously established as a "carbon counting device". However, in this study we present results which show that He-PDPID is more accurate in determining the percent composition of a hydrocarbon mixture and, because it is a universal detection method and can detect compounds that FID cannot, it is also more effective for determining the percent composition of mixtures containing organic compounds with a variety of other functional groups. 相似文献
6.
The possibility of simultaneous application of an electron capture (ECD) and a flame ionization detector (FID) connected to a glass capillary column for analyzing polynuclear aromatic hydrocarbons (PNA) has been investigated. The ECD/FID ratio is determined for 46 PNA compounds. The ratios vary from 0.02 to 117 with relative standard deviations better than 20 percent determined from 10 replicate analyses. The results suggest that the method may be used for obtaining additional evidence in identifying PNA in environmental samples. Impurities and transformation products in the standard were identified by computerized glass capillary gas chromatography/mass spectrometry. Quinones and diones are responsible for the high EC-response determined in some trace components in the standard. An application of the method is shown for PNA from particulates in urban atmospheres. 相似文献
7.
炼厂气是炼油工艺产生的各种气体的混合物,采用四阀六柱将炼厂气分离分解为3部分,以双TCD+FID检测器3通道气相色谱法快速分析炼厂气.FID通道用于分析烃类,一个TCD通道分析永久性气体和硫化物,另一个TCD通道分析氢气,采用面积归一化法定量计算分析结果.用该法测定了3种标准气体,测定值与标准值基本一致,测定结果的相对标准偏差小于8%.该法适用于测定包括液化气、烟气、裂解气等组分相近的样品组成. 相似文献
8.
A gas chromatographic system for the simultaneous acquisition of hydrocarbon and sulfur chromatograms was developed. Detection of sulfur compounds is achieved using a sulfur chemiluminescence detector (SCD) mounted in series with a flame ionization detector (FID). A constant fraction of the effluent of the FID is transferred to the SCD by means of a fixed restrictor. Unlike previous versions of this approach, the FID is not used to generate the chemiluminescent sulfur species. Rather, the FID is operated under optimum conditions for hydrocarbon analysis and a furnace is used to generate the chemiluminescent sulfur species. The system permits dual acquisition of the hydrocarbon and sulfur signals in a single analysis with a single column, since the detectors are operated in a serial fashion. The application of sulfur simulated distillation using this approach was examined, since this requires simultaneous universal and sulfur selective detection. Precision of absolute response of both the FID and SCD was typically less than 2% RSD for a standard reference material. 相似文献
9.
Summary The Chromatographic determination of residues ofN,N-dime-thylaniline and formaldehyde in penicillins is described.N,N-Di-methylaniline can be extracted from alkaline solutions inton-hep-tane in one step and determined by HPLC (ultraviolet detector) or by gas chromatography (FID or N-P FID) without further treatment. HPLC and GC with N-P FID proved to be equivalent. The detection limit is in the subg/g range, and the time for the chromatographic separation is only a few min. Formaldehyde can be detected by chromatography only as a derivative at trace levels. Formaldoxime, produced by reaction with hydroxylammonium chloride is determined by GC (N-P FID) at the/g level.
Presented at the 8th International Microchemical Symposium, Graz, August 25–30, 1980. 相似文献
Bestimmung toxischer Rückstände in Penicillinen
Zusammenfassung Die chromatographische Bestimmung von Rückständen anN,N-Dime-thylanilin und Formaldehyd in Penicillinen wurde beschrieben. Ersteres kann aus alkalischen Lösungen mitn-Heptan in einem Schritt extrahiert und ohne weitere Probenbehandlung mittels HPLC (UV-Detektor) als auch GC (FID oder N-P FID) bestimmt werden. HPLC und GC mit N-P FID erwiesen sich als gleichwertig. Die Nachweisgrenze liegt im sub-ppm-Be-reich, die chromatographische Bestimmung nimmt nur wenige Minuten in Anspruch. Formaldehyd ist im Spurenbereich chromatographisch nur in Kombination mit einer Derivatisierung nachweisbar. Das mit Hydroxyl-ammoniumchlorid gebildete Formaldoxim kann gaschromatographisch mit einem N-P FID im ppm-Bereich bestimmt werden.
Presented at the 8th International Microchemical Symposium, Graz, August 25–30, 1980. 相似文献
10.
K. Grob 《Journal of separation science》1980,3(6):286-290
The sensitivity of an FID may change when the carrier gas flow rate changes during a chromatographic run. Sample parts which are eluted at reduced FID sensitivity produce a reduced peak area, hence are discriminated as compared to other components. Sensitivity changes were studied for hydrogen as carrier gas. For the detector tested, differences in the carrier gas flow rates of 1 ml/min shifted the FID sensitivity by 1 to 5% (depending on the fuel gas supply). Thus the stability of the sensitivity is no longer ensured as soon as the carrier gas flow rate is changed manually or by an automatic programmer during an analysis. Sensitivity drifts may also occur during temperature programmed runs with a pressure regulated carrier gas supply since the gas flow through the capillary drops with increasing temperature. Such shifts in the response became noticeable as soon as relatively high carrier gas flow rates combined with long range temperature programmes were used. The typical patterns of such discriminations are shown, closing with a discussion on the possibilities for minimizing such undesired effects. 相似文献
11.
Yi Pan Zhi-Ang Li Xin Zhou Wei-Kang Wang Xing Wang Zheng Fang Cheng-Bin Zheng 《中国化学快报》2017,28(8):1670-1674
A new detection system consisted of a flame ionization detector (FID) and a sulfur chemiluminescence detector (SCD) was developed for sensitive and interference free determination of total sulfur in natural gas by non-separation gas chromatography. In this system, sulfur containing compounds and hydrocarbons were firstly burned in the FID using oxygen rich flame and converted to SO2, CO2 and H2O, respectively. The products from FID were transported into the SCD with hydrogen rich atmosphere wherein only SO2 could be reduced to SO and reacted with O3 to produce characteristic chemiluminescence. Therefore, the chemiluminescence of CO found in conventional SCD were eliminated because CO2 could not be reduced to CO under these conditions. The experimental parameters were systematically investigated. Limit of detection obtained by the proposed system is better than 0.5 μmol/mol for total sulfur and superior to those previously reported. The proposed method not only retains the advantages of the conventional SCD but also provides several unique advantages including no hydrocarbon interference, better stability, and easier calculation. The utility of this technique was demonstrated by the determination of total sulfur in real samples and two certified reference materials (GBW 06332 and GBW (E) 061320). 相似文献
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13.
Peter Klaffenbach Detlev Kronenfeld Timothy A. Peterson 《Journal of separation science》1998,21(12):649-652
The delivery of drugs through human skin using transdermal drug delivery (TDD) systems has become an established technology. A popular drug with that dosage form is nicotine for smoking cessation. A stability indicating method for the analysis of nicotine TDDs using gas chromatography (GC) with post-column effluent splitting to a flame ionization detector (FID) and a nitrogen-phosphorus detector (NPD) is described. FID detection gave reliable results with low day-to-day variability. The detector is relatively simple to operate. NPD detection offered enhanced sensitivity and specificity. The combination of both detectors resulted in a rugged method for content analysis with high sensitivity for detection of degradation products at low concentration levels. Despite a relatively simple sample preparation procedure no matrix interferences were observed. 相似文献
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15.
Maxwell C. Hunter Keith D. Bartle Alastair C. Lewis James B. McQuaid Peter Myers Paul W. Seakins Chris Van Tilburg 《Journal of separation science》1998,21(2):75-80
Two different gas chromatographic detectors, the helium ionization detector (HID) and the more commonly used flame ionization detector (FID), were used in parallel to compare their responses to a number of organic compounds. Atmospherically important oxygenated species were analyzed, as well as hydrocarbons and chlorinated and sulfur containing organics. The HID exhibited the better response to all compounds investigated, most notably to formaldehyde and higher oxygenates. A gas chromatographic system was developed to trap and analyze atmospheric organic compounds with HID detection. This required careful choice of the adsorbent material and removal of inorganic components (namely nitrogen and oxygen) before analysis. Real air samples were then taken and analyzed qualitatively for a range of olefinic and aromatic compounds. 相似文献
16.
R. Becker Matthias Koch Sigrid Wachholz Tin Win 《Accreditation and quality assurance》2002,7(7):286-289
Due to the utilisation of 1,1,2-trichlorotrifluoroethane (CFE) as extraction solvent the IR-spectrometric determination of
total petrol hydrocarbon (TPH) in soil according to ISO/TR 11046 has been replaced by gas chromatography/flame ionisation
detection (GC/FID) after extraction with a halogen-free solvent according to ISO/DIS 16703:2001. The results obtained with
both methods by field laboratories in three proficiency testing (PT) rounds are compared. The consensus means obtained with
GC/FID are typically 10%–20% (ranging between 0% and 25%) higher than those found with IR-spectroscopy. On the contrary, coefficients
of variation (CV) are roughly double in case of GC/FID and are briefly discussed against the background of the Horwitz equation.
Received: 19 November 2001 Accepted: 17 March 2002 相似文献
17.
《Analytical letters》2012,45(8):603-610
Abstract The design, construction and performance of an inexpensive multisample solvent evaporator assembled from readily available parts is described. Tubes containing solvent are heated in aluminum blocks under inert gas flow from a gas-divider manifold. The efficiency and uniformity of evaporation is satisfactory, and no substantial amounts of contaminants were observed in 100-fold solvent concentrates by gas chromatography with FID, FPD, and ECD detection. The assembly provides for an easy introduction of adsorbent trapping materials in the gas stream to remove any contaminants present in the gas. 相似文献
18.
Zusammenfassung In einem Gas-Chromatographen wird der FID durch einen neuen Photoionisationsdetektor (PID) ersetzt. Der Photoionisationsdetektor wird kurz beschrieben und auf seine operativen Vorteile (einfache Anwendung, Fehlen von Betriebsmitteln wie Brenngase usw.) hingewiesen. Es werden einige Messungen mit dem modifizierten Gerät vorgenommen und die Ergebnisse mit denen des FID verglichen. Bedingt durch systemspezifische Vorteile des Photoionisationsdetektors—verglichen mit dem FID ist der Rauschpegel stark vermindert und wegen des größeren Wirkungsgrades der Photoionisation steht ein höheres Signal zur Verfügung—sowie durch das Fehlen von O2 und seinen Problemen ist eine erhebliche Empfindlichkeitssteigerung des Gesamtsystems festzustellen. Außerdem ergibt sich, wiederum verglichen mit dem FID, ein weiterer Dynamikbereich. Weiter werden mit Hilfe des Photoionisationsdetektors gewonnene Meßergebnisse mit publizierten Ergebnissen anderer Detektoren verglichen und die Vorteile des PID aufgezeigt.
A new photoionization detector for gas chromatography
Summary In a commercially available GC the FID was replaced by a newly designed photoionization detector (PID). The PID and its operational advantages (ease of use, no neccessity for combustion gas and the related facilities) are described briefly. Some measurements are made with the such modified GC and the results are compared with those obtained with the FID. Specific advantages of the PID — compared to a FID — the noise level caused by the system is lower and (due to the higher ionization efficiency of the PID) the signal is larger — and due to the lack of oxygen and its altendant problems the overall system sensitivity is strikingly better. In addition, the dynamic range — again compared with the FID — is wider. Further, performance data obtained with the PID are compared with published data of other detectors and the advantages of the PID are shown clearly.相似文献
19.