Characterization of the flame photometric detector in the sulphur mode

Summary The effect of experimental conditions such as gas flow rates, detector and column temperatures on sulphur response are discussed. It is concluded that the response of the flame photometric detector is affected by the O/H ratio and the total gas flow. Column temperature has an important influence upon S₂ emission. It is shown that the sulphur response of the FPD is dependent on the compound containing the sulphur.     

Determination of the boiling point distribution of sulfur compounds in light cycle oil using GC with a flame photometric detector and pyrolyzer

A method has been developed to determine the boiling point distribution of sulfur compounds in light cycle oils (LCO'S). The method chosen for this analysis was GC with a flame photometric detector (FPD) and pyrolyzer. Tests were carried out to evaluate the recovery efficiency, repeatability, and accuracy of the method. Repeatabilities within 2% were obtained. The recovery of benzothiophenes and dibenzothiophenes was close to 100%; this was important because these are the major sulfur components in LCO's. No hydrocarbon or solvent interferences were observed with the use of the pyrolyzer, even for a 95% solvent level. Comparison with results from other techniques showed that the method accurately determined the levels of sulfur compounds in the LCO boiling point range.     

裂解色谱法研究渣油中硫化物的结构及组成特征

采用裂解气相色谱(PY-GC)方法研究重油中的大分子硫化物。实验考察了裂解时间和裂解温度对裂解反应的影响,在此基础上确定了裂解色谱条件,并分析了渣油裂解产物的组成。通过对大港、俄罗斯、前郭、孤岛及俄罗斯-大庆混合减压渣油等5种渣油的裂解实验,发现不同来源的渣油裂解产物中硫化物的组成和含量存在较大差异。实验中所得到的裂解产物中硫化物的组成为渣油中硫化物的组成提供了重要信息。     

Interference from elemental sulphur in the determination of organotins by gas chromatography with flame photometric detection

Elemental sulphur, a common constituent of marine sediments, has been shown to give dialkyl sulphides with the Grignard reagents commonly used to derivatize alkyltin species before their determination by gas chromatography with flame photometric detection (GC–FPD). Further, it has been demonstrated that even with the red filter for 610 nm (normally used for organotin compounds) fitted to the detector, sulphur compounds do give rise to an emission signal, which may be mistaken for tin emission from a pentylated or propylated alkyltin compound, as the respective retention times are in some cases quite close. © 1997 by John Wiley & Sons, Ltd.     

Monitoring of odorant components in British natural Gas

Summary The individual sulphur compounds that make up the odorant in natural gas are analysed with purpose-made equipment, using chromatographic separation and a flame photometric detector. Presented at the 15th International Symposium on Chromatography, Nürnberg, October 1984     

Evaluation and comparison of selective gas chromatographic detectors for the analysis of pesticide residues

Summary A series of studies is described on the evaluation and comparison of some selective gas chromatographic detectors used in pesticide residue analysis. A detailed study of the optimization and response characteristics of the CsBr and RbCl three-electrode alkali flame ionization detector for N and P compounds, the Coulson electrolytic conductivity detector in the nitrogen, sulphur and pyrolytic modes of operation and the sulphur phosphorus emission detector, a type of flame photometric detector, was carried out to obtain maximum sensitivity and reliability for the analysis of pesticide residues in various biological substrates. It was observed that the alkali flame and electrolytic conductivity detector responses to nitrogen compounds were of the same order, while the electrolytic conductivity detector was more sensitive than the flame photometric detector to sulphur compounds. Also, attempts were made to correlate the responses from these different detector systems using the insecticide chlorpyrifos which contains P, S, Cl and N atoms. The use of chlorpyrifos as an evaluation standard in verifying the acceptable performance of these types of detectors is recommended.Chemistry and Biology Research Institute Contribution No 901     

Determination of Toxic Organophosphorus Compounds by Specific and Nonspecific Detectors

Abstract

Sample preparation procedures and gas chromatography methodology are presented for the determination of tabun, sarin, soman, and VX in aqueous solutions. Extraction recoveries from chloroform were quantitative. Peak area ratios of organophosphorus compounds (OPs) to internal standard versus concentrations of OP were linear over the range of 10-1000 (μg/ml when determined by the flame ionization detector and 10-800 μg/ml when determined by the flame photometric detector. Imprecision occurring at low ng concentrations of VX was caused by its adsorption on the analytical column. Acceptable precision was regained by the addition of a weak base, such as atropine, to the sample extract prior to its injection onto the gas chromatograph (GC).     

气相色谱法测定桂皮中毒死蜱农药残留量

介绍了用气相色谱法检测毒死蜱农药在桂皮中的残留方法,选用Agilent 6890N气相色谱仪,DB-1701和HP-5双柱法、火焰光度检测器(FPD)和电子俘获检测器(ECD)双检测器来定性,外标法定量,并采用中性氧化铝柱净化样液,效果良好,节约检测成本,回收率为86.7%～93.4%,各项指标均满足有关要求.     

气相色谱表面发射火焰光度检测法测定汽油中的四乙基铅

本文介绍气相色谱表面发射漯焰光度法快速、简便地测定汽油中的四乙基铅，最小检测限为０．３ｎｇ。所得结果与气相色谱－原子吸收联用法基本一致。     

Determination of sulphur compounds in beer using headspace solid-phase microextraction and gas chromatographic analysis with pulsed flame photometric detection

A simple and sensitive method for the analysis of volatile and semi-volatile sulphur compounds in beer at trace levels was developed using headspace solid-phase microextraction (SPME) and gas chromatography with pulsed flame photometric detection. Different SPME fibres were tested and a Carboxen-polydimethylsiloxane coated fibre was found to be the most appropriate. The adsorption and desorption conditions were optimised. The effect of ethanol concentration in the sample on the extraction of analytes was examined. A 60 m non-polar capillary column preceded by a 10 m length of a polar column was found to be capable of separating a wide range of C1-C6 sulphur compounds. The pulsed flame photometric detector enabled increased sensitivity to be obtained over previous methods, such as dynamic headspace followed by conventional flame photometric detection or sulphur chemiluminescent detection, with high sulphur selectivity. Two sulphur compounds, 2-methyl-1-butanethiol and 3-methylthiophene, were identified in beer for the first time.     

A photometric detector driven by beta radiation

It was recently found that typical Chromatographic carrier gases such as argon or nitrogen could be used in a modified flame photometric detector for general or selective determination of eluted molecules. The detector was powered not by a flame but by a radioactively stimulated, mild discharge. The luminescence arose from the second positive system of nitrogen (in argon), and various emissions from aroyl-containing molecules (in nitrogen).This study describes experiments that take away not only the flame but also the discharge: The energy that produces the luminescence is derived solely from the beta decay of⁶³Ni. Because of this low power input, the sensitivity of the present beta-driven photometric detector (-PD) is limited to about 25 ppm of nitrogen (in argon), and to about 5 pg/s for benzaldehyde and other well-responding aroyl compounds (in nitrogen). In accordance with mechanisms postulated earlier, other types of molecules do not produce significant responses in the absence of an electrical field.Material taken from doctoral thesis     

A Dual-Channel Flame Photometric Detector with a Seperate Combustion Chamber

A new version of the dual-channel flame photometric detector is described for compounds containing phosphorus and sulphur. The sample is mixed with hydrogen before introduction into the detector. The burner is formed as a specific combustion chamber, which is separated from the emission chamber of the detector. Interference signals in the P-channel, caused by sulphur-containing compounds (crosstalk signals) are damped electrically. Thus the selectivity to hydrocarbons is increased by a factor of up to 10⁷, crosstalk signals are reduced by a factor of 10³ and flame stability is guaranteed (there are no flame-outs caused by amounts of up to 50 μl of liquid samples).     

气相色谱仪检定装置的使用方法

依据JJG 700–1999《气相色谱仪检定规程》介绍气相色谱仪检定装置的使用方法。检定项目包括载气流速稳定性、柱箱温度稳定性和程序升温重复性、衰减器换挡误差以及检测器的灵敏度。给出了热导检测器(TCD)、火焰离子化检测器(FID)、火焰光度检测器(FPD)、电子俘获检测器(ECD)和氮磷检测器(NPD)检定时的色谱条件及使用注意事项。正确使用气相色谱仪检定装置能保证仪器测量数据的准确可靠。     

Method for analysis of heavy sulphur compounds using gas chromatography with flame photometric detection

A method for analysis of heavy sulphur compounds in wines, based on gas chromatography (GC) with flame photometric detection, is reported. Wine samples preparation includes a dichloromethane liquid-liquid extraction followed by concentration under a nitrogen atmosphere. The extracted fraction was also analysed by GC-mass spectrometry. The method enables high recovery of sulphur compounds in wine and satisfies the requirements of repeatability and sensitivity. Applications of the method to red, white and Port wines are reported.     

Isolation and determination of dissolved organic sulphur compounds — development of the organic group parameter DOS

A procedure has been worked out for the determination of organic sulphur compounds (OSCs) in aqueous solution. They are isolated from water by solid phase extraction on macroporous resins and reversed-phase sorbents. The total sulphur content of the extracts is determined via a process of thermal cracking and hydrogenation (pyrohydrogenolysis) of small amounts of extract in a heated quartz tube (1100°C) flushed with hydrogen. Sulphur is detected at a wavelength of 394 nm in the hydrogen flame of a flame photometer. The flame photometric detector (FPD) is calibrated with a coulometric H₂S-generator. The procedure of solid phase extraction and subsequent pyrohydrogenolysis/flame photometry of the extracts can be used to determine the organic group parameter DOS (Dissolved Organic Sulphur) in the range of 20–1000 μg/1.     

Isolation and determination of dissolved organic sulphur compounds — development of the organic group parameter DOS

A procedure has been worked out for the determination of organic sulphur compounds (OSCs) in aqueous solution. They are isolated from water by solid phase extraction on macroporous resins and reversed-phase sorbents. The total sulphur content of the extracts is determined via a process of thermal cracking and hydrogenation (pyrohydrogenolysis) of small amounts of extract in a heated quartz tube (1100° C) flushed with hydrogen. Sulphur is detected at a wavelength of 394 nm in the hydrogen flame of a flame photometer. The flame photometric detector (FPD) is calibrated with a coulometric H₂S-generator. The procedure of solid phase extraction and subsequent pyrohydrogenolysis/flame photometry of the extracts can be used to determine the organic group parameter DOS (Dissolved Organic Sulphur) in the range of 20– 1000 μg/l. Received: 12 March 1996 / Revised: 25 April 1996 / Accepted: 30 April 1996     

Optimisation of the selectivity of a pulsed flame photometric detector for unknown compound screening

Identification of traces of chemical warfare agents (CWA) is generally performed with spectral methods such as mass spectrometry (MS) or NMR, but the use of element-specific detectors is most often required to extract interesting signals from gas chromatographic (GC) data heavily masked by natural interferents. The pulsed flame phosphorus detector (P-FPD) is able to detect phosphorus, sulphur and arsenic, and thus should be very well-suited to CWA detection. However, first results using standard operating conditions recommended by the manufacturer of P-FPD led to false positive detection of phosphorus-containing compounds on the sulphur line. Therefore, an optimisation process of the selectivity of P-FPD for phosphorus versus sulphur or arsenic was undertaken, and allowed to identify gate delay and gate width as crucial parameters for the performance of P-FPD. While selectivity could be significantly improved, unexpectedly, this resulted in a concurrent important loss of sensitivity (ca. 45%) for arsenic, which suggests that this detector should be carefully optimised with respect, and prior to its purported use.     

Chromatographic parameters derived for the non-linear response of a flame photometric detector

Summary A mathematical derivation of efficiency and resolution equations for use in conjunction with flame photometric detection of sulphur compounds is presented. These equations are similar to those for linear detection apart from the incorporation of the exponential response factor, n, in the denominator of the respective expressions for non-linear detection. The latter equations reduce to those usually recognised for linear detection if the value n=1 is substituted. Equating the column efficiency equations for linear and non-linear detection permits direct determination of the value of n.     

Analysis of sludge extracts by high resolution GC with selective detectors

Combination of various GC detectors by using a Varian effluent splitter with glass capillary columns has been found to be a rapid procedure for profiling organics extracted from sludges and river sediments. The selectivity and the increased sensitivity of the thermionic nitrogen-phosphorus detector (TSD), the electron capture detector (ECD), and the flame photometric detector (FPD) over the flame ionization detectors (FID) or mass spectrometers allow the detection of compounds present at trace levels without need for extensive sample cleanup. Furthermore, the combination of two selective detectors may supplement the information with regard to the chemical functionalities required for structure elucidation.     

Determination of triphenyltin hydroxide derivatives by capillary GC and tin-selective FPD

A new method for the determination of triphenyltin hydroxide using capillary column gas chromatography with a tin-selective flame photometric detector has been developed. Triphenyltin hydroxide and its potential metabolites are converted to methyl derivatives and separated on glass capillary columns coated with OV-101. Derivatization of triphenyltin hydroxide, triphenyltin chloride, diphenyltin dichloride, phenyltin trichloride, and bis-triphenyltin oxide is nearly quantitative with a minimum of redistribution products. The selectivity of the flame photometric detector is cearly demonstrated by the comparison of chromatographic profiles obtained from using both the flame photometric and flame ionization detectors. The use of this chromatographic system in the analysis of triphenyltin hydroxide in a fortified water sample demonstrates the potential use of this system in organotin residue chemistry.