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A microcountercurrent flame photometric detector [micro]cc-FPD) was adapted and optimized for ultrafast gas chromatographic (GC) separation and detection of organophosphor (OP) and organosulfur (OS) compounds on short chromatographic columns. Air and hydrogen are introduced to the [micro]cc-FPD from opposite directions, creating a hydrogen-rich flame. In this [micro]cc-FPD, combustion takes place between the burner tips without touching them. The separation between the tips and the flame reduces heat loss from the flame to the surrounding environment, resulting in low hydrogen consumption and a compact flame. The [micro]cc-FPD is capable of detecting very narrow (13 ms) chromatographic peaks. An ultrafast GC separation of a group of six OP and OS compounds is achieved within less than 5 s using fast temperature programming of a 0.5-m-long microbore column. Very fast separations are also demonstrated on a 1-m-long microfabricated column consisting of 150-[micro]m-wide, 240-[micro]m-deep channels, etched in a 1.9-cm square silicon chip, covered with a Pyrex wafer, and statically coated with dimethyl polysiloxane. With a hydrogen flow rate of 10 mL/min, the detection limit for OP is 12 pg of P/s and 3 ng of S/s for OS compounds at a signal-to-noise ratio of 2. The coupling of a microfabricated column and a miniature FPD is an important step toward the development of a miniaturized GC-FPD capable of ultrafast detection of low levels of OP and OS compounds.

The development and study of a protective module that removes dust from an air stream based on improved cyclone technology (cyclone separator – CSR) are described. In previous work, we developed a standard CSR and coupled it to a chemical detector. This coupling provides an excellent solution for a few hours of operation required for the detection of hazardous materials in cases of emergency. However, environmental monitoring requires to prolong operation, which requires handling large amounts of dust. This can be accomplished by improving the CSR and increasing its capability to remove fine dust particles that may interfere with the proper operation of the chemical detector and other electronic devices that are often required in environmental applications. Performance is improved by adding low airflow pumping-out from the CSR dustbin. Dust removal efficiency improves by factor 3–7 for small particles, which is valuable for prolonging outdoor operation. The improved CSR performances are constant over time, which is adventurous for prolonging operation of sensitive equipment in a harsh environment. [ABSTRACT FROM AUTHOR]

The development and testing of a module that removes dust from air based on cyclone technology and its coupling to a chemical detector are described. This development was performed in a laboratory facility that is capable of simulating a harsh environment in which the target material can be mixed with dust at controlled climatic conditions. The size-dependent removal efficiency of the module was tested at different operational conditions. For dust particles of 5 µm and higher, removal efficiency is about 100%. The efficiency for smaller particles is lower, and the overall efficiency is 97%. No significant adverse effect on the detector (flame photometric detector) performance at low to moderate target material concentrations (100 µg/m3), even at high dust concentration, is observed. The cyclone operation does not require the use of consumable and its maintenance is minimal. Power consumption is 15W, which is acceptable for a fixed site or car transportable system and can be further reduced for the handheld version. [ABSTRACT FROM AUTHOR]