Belt-Mounted Micro-Gas-Chromatograph Prototype for Determining Personal Exposures to Volatile-Organic-Compound Mixture Components
| Autor: | Robert Nidetz, Edward T. Zellers, Bryan M. Brookover, Seth J. Peterson, Junqi Wang, William H. Steinecker, Nicolas Nuñovero |
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| Rok vydání: | 2019 |
| Předmět: |
Detection limit
chemistry.chemical_classification Battery (electricity) Volatile Organic Compounds Chromatography Gas Threshold limit value Calibration curve Extramural 010401 analytical chemistry Analytical chemistry 010402 general chemistry 01 natural sciences 0104 chemical sciences Analytical Chemistry chemistry Breath Tests Microsystem Air Pollution Indoor Humans Volatile organic compound Gas chromatography Environmental Monitoring |
| Zdroj: | Analytical chemistry. 91(7) |
| ISSN: | 1520-6882 |
| Popis: | We describe a belt-mountable prototype instrument containing a gas chromatographic microsystem (μGC) and demonstrate its capability for near-real-time recognition and quantification of volatile organic compounds (VOCs) in moderately complex mixtures at concentrations encountered in industrial workplace environments. The μGC comprises three discrete, Si/Pyrex microfabricated chips: a dual-adsorbent micropreconcentrator-focuser for VOC capture and injection; a wall-coated microcolumn with thin-metal heaters and temperature sensors for temperature-programmed separations; and an array of four microchemiresistors with thiolate-monolayer-protected-Au-nanoparticle interface films for detection and recognition-discrimination. The battery-powered μGC prototype (20 × 15 × 9 cm, ∼2.1 kg sans battery) has on-board microcontrollers and can autonomously analyze the components of a given VOC mixture several times per hour. Calibration curves bracketing the Threshold Limit Value (TLV) of each VOC yielded detection limits of 16-600 parts-per-billion for air samples of 5-10 mL, well below respective TLVs. A 2:1 injection split improved the resolution of early eluting compounds by up to 63%. Responses and response patterns were stable for 5 days. Use of retention-time windows facilitated the chemometric recognition and discrimination of the components of a 21-VOC mixture sampled and analyzed in 3.5 min. Results from a "mock" field test, in which personal exposures to time-varying concentrations of a mixture of five VOCs were measured autonomously, agreed closely with those from a reference GC. Thus, reliable, near-real-time determinations of worker exposures to multiple VOCs with this wearable μGC prototype appear feasible. |
| Databáze: | OpenAIRE |
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