Gas phase electrochemical detection of single latex particles

Phys. Chem. Chem. Phys.

2006

Premixed hydrogen/oxygen flame doped with ionisable alkali metals was considered as a dilute electrolyte. Two identical premixed flames which were in physical contact, served as a two compartment flame electrolyte cell. Five different electrochemical cells were studied, each containing a different combination of three alkali metals, Li, K and Cs. Pairs of boron doped diamond (BDD) and platinum electrodes were used to measure the overall zero current cell potential. The total potential measured across the cell was shown to be the sum of the mixed potential, dependent on the identity of ionised species present in the flame, and the diffusion potential originating at the junction between the two flames. Classical kinetic molecular theory and electrochemical theory of mixed potentials have been applied to account for the potential difference measured across these gas phase electrochemical cells. The relative merits of both models are discussed in the context of the experimental results obtained.

Section: Current Measurementssupporting

confidence: 52%

Plasma electrochemistry: potential measured at boron doped diamond and platinum in gaseous electrolyte

Hadzifejzovic

Galiani

Phys. Chem. Chem. Phys.

2006

“…This way the detection has a physical basis which means robustness and high sensitivity. Previous work in our lab has shown that flames can indeed be used as conductive gas-phase media for electrochemical studies. − In one such study the detection of latex beads in a H 2 /O 2 /N 2 flame was demonstrated by means of potentiometry …”

mentioning

confidence: 99%

Potentiometric Detection of Model Bioaerosol Particles

Sarantaridis

2010

Anal. Chem.

Self Cite

A new technique for the detection of bioaerosols is presented, utilizing particle combustion/ionization in a premixed hydrogen/oxygen/nitrogen flame plasma, followed by gas phase electrochemical detection. Bermuda grass pollen (Cynodon dactylon, one of the most common causes of pollen allergy) and black walnut pollen (Juglans nigra) were used as model bioaerosol particles. We demonstrate that single particle detection can be comfortably achieved by zero current potential measurements between two platinum electrodes, giving potential signals of over 800 mV and unique fragmentation features which may be used for differentiating between species. The high sensitivity is due to the inherent amplification through flame fragmentation, gasification and ionization; a single pollen grain of 25 μm diameter can give a plume of combustion products measuring 4 mm in diameter. The physical basis of the potential difference is a mixed interfacial potential with an additive diffusion/junction potential due to the increase in ionization from the pollen combustion. The results suggest this methodology may be applied to the detection of particulates composed of ionizable species (organic or inorganic) in gaseous environments, such as bacteria, viruses, pollen grains, and dust. Its effectiveness will depend on the propensity of the target particle to combust and generate voltages under specific flame and electrode conditions.

“…A slightly related approach which relies on the fragmentation of airborne particles is plasma assisted fragmentation followed by plasma electrochemical detection. 50,133,134 Here the advantage is that the fragmentation and the detection are performed in unison. The detection is based on the measurement of a zero current potential between two or more electrodes to electrochemically image the plume of fragmentation products from single particle combustion events.…”

Section: Molecular Based Analysis or Recognitionmentioning

confidence: 99%

Detection and analysis of airborne particles of biological origin: present and future

2011

Analyst

Self Cite

Detection and identification of bioaerosols in the environment presents a unique analytical challenge. The complexity and variation of the analyte, coupled with the disparity of the end users required information has led to the establishment of a huge number of approaches for detection. In general these approaches may be divided into two elements; sampling, describing the physical process used to capture the bioaerosols and analysis, the method by which the bioaerosols are counted and identified. There are a large number of methodologies for both these elements, mainly due to the diversity of applications, and a very unhealthy absence of consensus on standardisation for these approaches. This is an analytical application where 'one size does not fit all'; nevertheless standardisation is still essential. The focus of this review will clarify the challenge, by discussing the many different bioaerosols to be measured and the required user output, also to give a critique of the various analytical approaches that exist to date, including other promising methodologies that could be applied.