高灵敏度脉冲火焰光度检测器的研制与性能测试

doi:10.3724/SP.J.1123.2026.03027

摘要/Abstract

摘要：

常规火焰光度检测器（FPD）在复杂烃类基体中易受背景发光和火焰波动影响，限制了痕量硫化物的高灵敏、稳定检测。本工作基于硫延迟发光的时间分辨特性，研制了一种脉冲式火焰光度检测器（PFPD），并围绕结构设计、运行参数优化、硫延迟发光响应及仪器性能测试开展系统研究。检测器由燃烧与点火模块、气路模块、光学采集与检测模块、温度控制模块以及机械支撑与密封模块组成。其中，引火室用于建立稳定的周期性点火，样品气体在石英燃烧室内实现脉冲燃烧，产生的硫延迟发光经滤光与导光组件传输后由光电倍增管（PMT）采集。气路模块采用两路电子压力控制单元（EPC）分别调控引火室与燃烧室供气，实现点火条件与分析燃烧条件的解耦调控。在此基础上，建立了“点火基准建立-燃烧室供气参数优化-检测温度与信号增益匹配”的窗口化优化流程。结果表明，将引火室氢气和空气流量分别固定为8.0 mL/min和19.0 mL/min，脉冲火焰稳定且规律，可作为引火室的点火基准；在该基准下，将燃烧室氢气和空气流量分别调节为5.0 mL/min和3.7 mL/min，此时硫响应的峰面积、灵敏度和信噪比（SNR）同步达到最优；检测器温度约150 ℃时，硫延迟发光响应较强；PMT电压在590~710 V范围内可获得较好的SNR提升。采用10 μmol/mol的H₂S标准气体经动态稀释后评价线性范围，并以1.1 μmol/mol的H₂S标准气体开展定量重复性和硫检出限测试。连续7次进样的定量重复性为0.37%，硫检出限为4.1×10⁻¹³ g/s，线性范围约为2个数量级。该PFPD具有稳定的脉冲燃烧行为和痕量硫定量能力，可为PFPD结构设计、参数优化、硫延迟发光响应和性能测试提供参考。

关键词: 脉冲式火焰光度检测器, 硫延迟发光, 定量重复性, 硫检出限, 线性范围

Abstract:

The conventional flame photometric detector （FPD） is widely used for sulfur-selective gas chromatography. However， the FPD is sensitive to hydrocarbon backgrounds. Its sulfur response also depends strongly on flame stability. These factors limit stable trace sulfur determination in complex matrices. A pulsed flame photometric detector （PFPD） provides a time-resolved approach to this problem. Sulfur emission appears later than most hydrocarbon background emissions after pulsed combustion. A suitable acquisition window can therefore improve sulfur selectivity. In this study， a high-sensitivity single-channel PFPD was designed and tested. The aim was to establish reproducible operating conditions for trace sulfur analysis. The detector consisted of five functional modules： the combustion and ignition module， the gas supply module， the optical collection and detection module， the temperature-control module， and the mechanical support and sealing module. The combustion zone consisted of a vertically mounted quartz chamber. The chamber had an outer diameter of 4 mm. Its inner diameter was 2 mm. Its total length was 17.5 mm. The effective combustion length was 12 mm. The calculated chamber volume was 37.68 mm³. Numerical simulation was used to examine flame propagation and self-extinction. A 12 mm effective length maintained a stable finger-shaped flame front. The flame was self-terminated near the lower limiting orifice at about 1.97 ms. The hydroxyl radical mass fraction decreased close to baseline within 5 ms， whereas the temperature decayed more gradually and approached its initial level at approximately 30 ms. These results supported the chamber design for periodic pulsed combustion. The optical unit used a quartz light guide and a BG-12 band-pass filter. The filter matched the sulfur emission band near 394 nm. A photomultiplier tube （PMT） recorded the time-resolved emission signal. Two electronic pneumatic control （EPC） units were used for gas regulation. One unit controlled hydrogen and air for the ignition chamber. The other unit controlled hydrogen and air for the combustion chamber. This design separated ignition conditions from analytical combustion conditions. It also reduced uncertainty caused by coupled gas adjustment. The optimization started with the ignition chamber. Then the combustion chamber was optimized under the fixed ignition baseline. Finally， detector temperature and PMT voltage were evaluated. Peak area， sensitivity， and signal-to-noise ratio （SNR） were used as indicators. Gas chromatographic tests used a sulfur-specific quartz capillary column. Nitrogen was used as the carrier gas. The gate delay was 6 ms. The gate width was 18 ms. The trigger level was 500 mV. A stable pulsed flame was obtained at an ignition-chamber hydrogen flow of 8.0 mL/min. The corresponding ignition-chamber air flow was 19.0 mL/min. Under this ignition baseline， the combustion chamber was further adjusted. A higher sulfur response was obtained at 5.0 mL/min hydrogen. The corresponding air flow was 3.7 mL/min. Detector temperature also affected the delayed sulfur emission. The response was low at 110-130 ℃. At about 150 ℃， the delayed sulfur signal was higher. Peak area and sulfur sensitivity were also higher at this temperature. Higher temperatures from 170 to 250 ℃ reduced the peak area and sensitivity. PMT voltage affected signal amplitude， SNR， and waveform fidelity. Increasing the voltage from 590 to 710 V improved the SNR. At 730 V， the delayed emission plateau showed peak clipping. This behavior indicated saturation or nonlinear response in the detection chain. Dynamic dilutions of a 10 μmol/mol hydrogen sulfide （H₂S） standard gas were used to evaluate the linear range. A 1.1 μmol/mol H₂S standard gas was used for the quantitative repeatability test and， after 30-fold dynamic dilution， for determination of the sulfur detection limit. The quantitative repeatability， evaluated from the peak areas of seven consecutive injections， was 0.37%. The sulfur detection limit was 4.1×10⁻¹³ g/s， and the linear range spanned approximately two orders of magnitude. The developed PFPD showed stable pulsed combustion behavior. It also provided reliable quantitative response for trace sulfur detection. The dual-EPC design helped clarify the relationship between ignition and analytical combustion. The optimized conditions provide an experimental basis for self-developed PFPD systems.

Key words: pulsed flame photometric detector （PFPD）, delayed sulfur emission, quantitative repeatability, sulfur detection limit, linear range

中图分类号:

O658

陈骏彬, 蔡浩原, 邓智瀚, 金昱杰, 孙建海. 高灵敏度脉冲火焰光度检测器的研制与性能测试[J]. 色谱, 2026, 44(9): 1059-1073.

CHEN Junbin, CAI Haoyuan, DENG Zhihan, JIN Yujie, SUN Jianhai. Development and performance testing of a high-sensitivity pulsed flame photometric detector[J]. Chinese Journal of Chromatography, 2026, 44(9): 1059-1073.

图/表 22

图1 PFPD的结构组成及火焰传播和光学检测路径示意图

Fig. 1 Structural configuration of the PFPD and schematic illustrations of its flame-propagation process and optical detection patha. overall structure of the detector and division of functional modules； b. schematic illustration of the flame propagation path； c. schematic illustration of the optical detection path.PFPD： pulsed flame photometric detector； PMT： photomultiplier tube.

图2 不同燃烧室有效长度（L）下火焰前锋形态及·OH响应特征比较

Fig. 2 Comparison of flame front morphology and ·OH response characteristics at different effective combustion chamber lengths （L）a. representative temperature field distributions of flame fronts at different effective lengths； b. transient ·OH mass fraction response curves at the midpoint of the chamber axis at different effective lengths.Combustion chamber inner diameter： 2 mm； combustion chamber H2 flow： 2.0 mL/min； combustion chamber air flow： 3.5 mL/min.

图3 PFPD气路图

Fig. 3 PFPD gas flow diagramEPC： electronic pneumatic control. The gas flow diagram was prepared with the assistance of Shandong Lunan Ruihong Chemical Instrument Co.， Ltd.， based on the actual experimental system.

图4 PFPD工作原理

Fig. 4 PFPD operating principle

图5 燃烧室内火焰传播与自熄灭过程的温度场仿真结果

Fig. 5 Simulated temperature-field evolution during flame propagation and self-extinction in the combustion chamberEffective length： 12 mm. Other conditions are the same as in Fig. 2. The times shown on the panels denote the elapsed time after ignition.

图6 监测点处·OH质量分数与温度的瞬态响应曲线

Fig. 6 Transient responses of ·OH mass fraction and temperature at the monitoring pointConditions are the same as in Fig. 5. The monitoring point is located at the midpoint of the chamber axis.

表1 引火室独立点燃实验条件

Table 1 Independent ignition test conditions for the ignition chamber

Parameter	Value
Combustion chamber H₂ flow/（mL/min）	0
Combustion chamber air flow/（mL/min）	0
Combustion chamber N₂ flow/（mL/min）	1.5
Ignition chamber H₂ flow/（mL/min）	0
Ignition chamber air flow/（mL/min）	16.0
PMT voltage/V	630
Trigger level/mV	500
Ignition voltage/V	6.28
Detector temperature/℃	150

图7 不同引火室H2流量条件下燃烧脉冲的时间波形

Fig. 7 Time waveform of combustion pulses under different ignition chamber H2 flow conditionsCombustion chamber H2 flow： 0 mL/min； combustion chamber air flow： 0 mL/min； ignition chamber air flow： 16.0 mL/min.

表2 固定引火室H2流量（8.0 mL/min）并逐步提高引火室空气流量时的气体配比与燃烧频率

Table 2 Gas flow ratios and combustion frequency at a constant ignition chamber H2 flow （8.0 mL/min） with stepwise increases in ignition chamber air flow

Ignition chamber air flow/（mL/min）	Ignition chamber H₂/Air	Combustion frequency/Hz
13	0.62	0.64
14	0.57	2.08
15	0.53	2.56
16	0.50	3.03
17	0.47	3.23
18	0.44	3.57
19	0.42	3.85

表3 固定燃烧室空气流量（3.5 mL/min）并逐步提高燃烧室H2流量时的气体配比与燃烧频率

Table 3 Gas flow ratios and combustion frequency at a constant combustion chamber air flow （3.5 mL/min） with stepwise increases in combustion chamber H2 flow

Combustion chamber H₂ /（mL/min）	Combustion chamber H₂/Air	Combustion frequency/Hz
0	0	4.00
1.0	0.29	4.17
2.0	0.57	4.17
3.0	0.86	4.35
4.0	1.14	4.35
5.0	1.43	4.76

图8 不同燃烧室H2流量条件下燃烧脉冲的时间波形

Fig. 8 Time waveform of combustion pulses under different H2 flow conditions in the combustion chamberCombustion chamber air flow： 3.5 mL/min； ignition chamber H2 flow： 8.0 mL/min； ignition chamber air flow： 19.0 mL/min.

图9 氧气不足工况下硫发光响应的时间波形

Fig. 9 Time waveform of sulfur luminescence response under oxygen-deficient conditionsCombustion chamber H2 flow： 5.0 mL/min； combustion chamber air flow： 3.5 mL/min； ignition chamber H2 flow： 8.0 mL/min； ignition chamber air flow： 19.0 mL/min.

图10 不同燃烧室空气流量下硫发光响应三维叠加图

Fig. 10 Three-dimensional overlay of sulfur luminescence response at different combustion chamber air flow ratesCombustion chamber H2 flow： 5.0 mL/min； ignition chamber H2 flow： 8.0 mL/min； ignition chamber air flow： 19.0 mL/min

图11 峰面积、检测灵敏度与SNR随燃烧室空气流量的热力图（数据已归一化）

Fig. 11 Heat map of peak area， detection sensitivity， and signal-to-noise ratio （SNR） as a function of combustion-chamber air flow rate （Data normalized）

图12 不同检测器温度下硫发光响应三维叠加图

Fig. 12 Three-dimensional overlay of sulfur luminescence response at different detector temperaturesCombustion chamber H2 flow： 5.0 mL/min； combustion chamber air flow： 3.7 mL/min； ignition chamber H2 flow： 8.0 mL/min； ignition chamber air flow： 19.0 mL/min.

图13 峰面积、检测灵敏度与SNR随温度变化的热力图（数据已归一化）

Fig. 13 Heat map of peak area， detection sensitivity， and SNR as a function of temperature （data normalized）

图14 不同PMT电压下硫发光响应的三维叠加图

Fig. 14 Three-dimensional overlay of sulfur luminescence response at different PMT voltagesConditions are the same as in Fig. 12.

图15 峰高、SNR和基线噪声随PMT电压的变化

Fig. 15 Peak height， SNR， and baseline noise versus PMT voltageThe error bars on the peak height and SNR bars represent the standard deviation （SD） of repeated measurements （n=7）. All error bars are shown on the original measurement scale without any amplification.

图16 烃类与硫在PFPD中的延迟发光时间响应曲线

Fig. 16 Time-resolved delayed luminescence response curves of hydrocarbons and sulfur in the PFPD

图17 PFPD硫通道峰面积与H2S物质的量分数的线性拟合曲线

Fig. 17 Linear calibration curve of sulfur-channel peak area versus H2S amount fraction for the PFPD

图18 1.1 μmol/mol H2S连续7次进样的色谱图

Fig. 18 Chromatograms of seven consecutive injections of 1.1 μmol/mol H₂S

表4 本研究PFPD与商业化硫检测器主要性能指标对比

Table 4 Comparison of the main performance metrics of the developed PFPD and commercial sulfur detectors

Detector	Sulfur detection limit/（g/s）	Linear range	Quantitative repeatability
PFPD developed in this work	4.1×10^-13	2 orders of magnitude	0.37% （1.1 μmol/mol H₂S）
5383 PFPD^{［17，19］}	1×10^-12	2.4 orders of magnitude	11% （0.657 μmol/mol H₂S）
Nexis FPD-2030^{［20，21］}	2×10^-12	3 orders of magnitude	0.91% （1 μmol/mol thiophene）

参考文献

[1]	Cao J， Sun Q， Zhao D， et al. J Hazard Mater， 2020， 385： 121511
[2]	Ou Y， Wu M， Yu Y， et al. Sci Total Environ， 2024， 929： 172478
[3]	Spatolisano E， Restelli F， Pellegrini L A， et al. Energies， 2024， 17（3）： 620
[4]	Zhang X， Qiu X， Wang R. Catalysts， 2024， 14（12）： 952
[5]	Ma L， Zhao R， Li J， et al. Environ Pollut， 2024， 350： 123946
[6]	Chen Z X， Zhou L， Wu S H， et al. Natural Gas Industry， 2025， 45（5）： 150
	陈梓浔，周理，吴姝虹，等. 天然气工业， 2025， 45（5）： 150
[7]	Syty A， Dean J A. Appl Opt， 1968， 7（7）： 1331
[8]	Fair R W， Thrush B A. Trans Faraday Soc， 1969， 65： 1208
[9]	Cheskis S， Atar E， Amirav A. Anal Chem， 1993， 65（5）： 539
[10]	Amirav A， Jing H. Anal Chem， 1995， 67（18）： 3305
[11]	Jing H， Amirav A. J Chromatogr A， 1998， 805（1/2）： 177
[12]	Kalontarov L， Jing H， Amirav A， et al. J Chromatogr A， 1995， 696（2）： 245
[13]	Aue W A， Eisener C G， Gebhardt J A， et al. J Chromatogr A， 1995， 699（1/2）： 195
[14]	Catalan L J J， Liang V， Jia C Q. J Chromatogr A， 2006， 1136（1）： 89
[15]	Massimi N， Polvara E， Invernizzi M， et al. Chem Eng Trans， 2024， 112： 91
[16]	Torres-Herrera S， González-Cortés J J， Almenglo F， et al. J Hazard Mater， 2022， 424： 127667
[17]	Analytical OI. 5383 PFPD Pulsed Flame Photometric Detector Operator Manual. ［2026-02-28］. https://www.ysi.com/File%20Library/Documents/Manuals/Pulsed-Flame-Photometric-Detector-Operator-Manual.pdf
[18]	GB/T 32190-2015
[19]	Elmore C， Duffy M. Am Lab， 2016， 48（2）： 20
[20]	Corporation Shimadzu. Nexis GC-2030 Specifications. ［2026-04-12］.https://www.shimadzu.com.sg/an/sites/shimadzu.com.sg.an/files/pim/pim_document_file/sap_an/spec_sheet/25256/Specs_Nexis_GC-2030_%5Bc184e042E%5D.pdf
[21]	Corporation Shimadzu. Analysis of Thiophene in Benzene. ［2026-04-12］. https://www.shimadzu.com/an/sites/shimadzu.com.an/files/pim/pim_document_file/applications/applica tion_note/13392/jpc117007.pdf