Detection of Pesticide Residues on Individual Particles

Whiteaker, Jeffrey R.; Prather, Kimberly A.

doi:10.1021/ac025771v

Cited by 24 publications

(13 citation statements)

References 37 publications

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“…A field-portable ATOFMS instrument was used to measure the size and composition of single aerosol particles at the Bakersfield sampling site between 9 January 1999 and 27 January 1999 (Whiteaker et al 2002;Whiteaker and Prather 2003). The electronics of this instrument were similar to those used in the 1996 Allen et al 2000) and 1997 field experiments (Bhave et al 2002;Pastor et al 2003).…”

Section: Methodsmentioning

confidence: 99%

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Instrument Busy Time and Mass Measurement using Aerosol Time-of-Flight Mass Spectrometry

Allen

Bhave

Whiteaker

et al. 2006

Aerosol Science and Technology

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Aerosol Time-of-Flight Mass Spectrometry (ATOFMS) instruments have been used widely to measure the size and composition of single ambient aerosol particles. ATOFMS data do not directly and quantitatively represent aerosol composition because the instruments exhibit non-linear response to particle concentration, size, and composition. Our approach is to analyze separately the components of non-linear ATOFMS response using field sampling data in order to understand ATOFMS response to ambient aerosols so that ATOFMS data can be scaled to more closely represent ambient aerosols. In this work we examine the effect of instrument busy time, mainly the time to process and save data, on ATOFMS response to ambient aerosols sampled during the 1999 Bakersfield Instrument Intercomparison Study (BIIS). During this study an ATOFMS instrument was operated alternately in normal and fast scatter data acquisition modes. In fast scatter mode, the instrument does not record mass spectra, minimizing instrument busy time; these data were used to determine particle arrival rates. Busy time in normal mode was found by a comparison of the number of particles detected to that expected for a Poisson process modified

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Section: Methodsmentioning

confidence: 99%

“…This period was characterized by low wind speed and the presence of a dense fog in the evening and occasionally during the day. For discussion of the ATOFMS data over the entire BIIS experiment, see (Whiteaker et al 2002) and (Whiteaker and Prather 2003).…”

Section: Particle Detection Ratesmentioning

confidence: 99%

Instrument Busy Time and Mass Measurement using Aerosol Time-of-Flight Mass Spectrometry

Allen

Bhave

Whiteaker

et al. 2006

Aerosol Science and Technology

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“…The absorption of photons depends on the optical properties of the chemical components of the particle, with important implications for core-shell or multi-component particles (Cahill et al, 2015). Reported approaches to improve the quantitative abilities of SPMS include two-step vaporization-ionization, where a CO 2 laser was used prior to excimer laser ionization for the evaporation of the particles (Cabalo et al, 2000;Morrical et al, 1998;Whiteaker and Prather, 2003;, or the use of a high power density Nd:YAG laser of 5 ns pulse duration with 100 mJ pulse energy (> 10 10 W m −2 ) (Lee et al, 2005;Mahadevan et al, 2002;Zhou et al, 2007). Lee and Mahadevan found that the kinetic energy of ions produced from ns-laser pulses is proportional to the particle size with a power law relationship, which influences ion detection efficiency in traditional time-of-flight mass spectrometer optics.…”

Section: Introductionmentioning

confidence: 99%

Exploring femtosecond laser ablation in single-particle aerosol mass spectrometry

et al. 2018

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Abstract. Size, composition, and mixing state of individual aerosol particles can be analysed in real time using singleparticle mass spectrometry (SPMS). In SPMS, laser ablation is the most widely used method for desorption and ionization of particle components, often realizing both in one single step. Excimer lasers are well suited for this task due to their relatively high power density (10 7 -10 10 W cm −2 ) in nanosecond (ns) pulses at ultraviolet (UV) wavelengths and short triggering times. However, varying particle optical properties and matrix effects make a quantitative interpretation of this analytical approach challenging. In atmospheric SPMS applications, this influences both the mass fraction of an individual particle that is ablated, as well as the resulting mass spectral fragmentation pattern of the ablated material. The present study explores the use of shorter (femtosecond, fs) laser pulses for atmospheric SPMS. Its objective is to assess whether the higher laser power density of the fs laser leads to a more complete ionization of the entire particle and higher ion signal and thus improvement in the quantitative abilities of SPMS. We systematically investigate the influence of power density and pulse duration on airborne particle (polystyrene latex, SiO 2 , NH 4 NO 3 , NaCl, and custom-made core-shell particles) ablation and reproducibility of mass spectral signatures. We used a laser ablation aerosol time-of-flight single-particle mass spectrometer (LAAPTOF, AeroMegt GmbH), originally equipped with an excimer laser (wavelength 193 nm, pulse width 8 ns, pulse energy 4 mJ), and coupled it to an fs laser (Spectra Physics Solstice-100F ultrafast laser) with similar pulse energy but longer wavelengths (266 nm with 100 fs and 0.2 mJ, 800 nm with 100 fs and 3.2 mJ). We successfully coupled the freefiring fs laser with the single-particle mass spectrometer employing the fs laser light scattered by the particle to trigger mass spectra acquisition. Generally, mass spectra exhibit an increase in ion intensities (factor 1 to 5) with increasing laser power density (∼ 10 9 to ∼ 10 13 W cm −2 ) from ns to fs laser. At the same time, fs-laser ablation produces spectra with larger ion fragments and ion clusters as well as clusters with oxygen, which does not render spectra interpretation more simple compared to ns-laser ablation. The idea that the higher power density of the fs laser leads to a more complete particle ablation and ionization could not be substantiated in this study. Quantification of ablated material remains difficult due to incomplete ionization of the particle. Furthermore, the fslaser application still suffers from limitations in triggering it in a useful time frame. Further studies are needed to test potential advantages of fs-over ns-laser ablation in SPMS.

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“…Many of those compounds are of environmental concern due to their production quantities, toxicity, persistence, and tendency to bioaccumulate (Schwarzenbach, Gschwend, & Imboden, 1993DeCaprio, 1997;Eganhouse, 1997;Takada et al, 1997;Aboul-Kassim & Simoneit, 2001). They can enter the hydrosphere (Hites, 1973(Hites, , 1977Lopez-Avila & Hites, 1980;Poiger et al, 1996;Leeming et al, 1997;Suter et al, 1997Suter et al, , 1999Simonich et al, 2000), atmosphere (Atlas et al, 1993;Baker & Hites, 1997;Hillery, Basu, & Hites, 1997;Strandberg et al, 2001;Whiteaker & Prather, 2003), geosphere into soils and sediments (Hom et al, 1974;Eglinton, Simoneit, & Zoro, 1975;Beller & Simoneit, 1986, 1988Kumata, Takada, & Ogura, 1997;Reiser, Toljander, & Giger, 1997;Stoll et al, 1997;Rogge, Medeiros, & Simoneit, 2004a-c), and up the food chain in biota (Risebrough et al, 1967;Bowes et al, 1973;Goldberg et al, 1978;Spitzer et al, 1978;Jarman et al, 1992Jarman et al, , 1993Simonich & Hites, 1995a). These applications of MS will keep increasing as more problems become evident, and as the sensitivities of the instrumental methods increase to ever-improved detection limits.…”

Section: B Anthropogenic Tracer Compoundsmentioning

confidence: 99%

“…Time-of-flight mass spectrometry (TOFMS) is beginning to be applied in atmospheric chemistry to elucidate organic compounds including biomarkers, on single aerosol particles (Alvarez, Vezmar, & Whetten, 1998;Noble & Prather, 2000;Angelino, Suess, & Prather, 2001;Whiteaker & Prather, 2003). The organic matter of individual aerosol particles is vaporized by laser and ionized in the TOFMS.…”

Section: Time-of-flight Mass Spectrometrymentioning

confidence: 99%

A review of current applications of mass spectrometry for biomarker/molecular tracer elucidations

Simoneit

2004

Mass Spectrometry Reviews

130

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Mass spectrometry, especially coupled with gas chromatography or tandem, is the analytical method of choice in elucidations of biomarker compounds present in organic mixtures extracted from geological, environmental, or biological samples. This review describes the biomarker concept; i.e., the precursor natural products to the geological/environmental derivatives, and their application as tracers in the geosphere and ambient environment. The mass spectrometric methods currently utilized for such analyses are reviewed, and typical examples of applications are described with a general key to the literature. © 2004 Wiley Periodicals, Inc., Mass Spec Rev 24:719–765, 2005

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Detection of Pesticide Residues on Individual Particles

Cited by 24 publications

References 37 publications

Instrument Busy Time and Mass Measurement using Aerosol Time-of-Flight Mass Spectrometry

Instrument Busy Time and Mass Measurement using Aerosol Time-of-Flight Mass Spectrometry

Exploring femtosecond laser ablation in single-particle aerosol mass spectrometry

A review of current applications of mass spectrometry for biomarker/molecular tracer elucidations

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