The Use of Hypodermic Needles as Critical Orifices in Air Sampling

Lodge, James P.; Pate, J. B.; Ammons, Blair E.; Swanson, G

doi:10.1080/00022470.1966.10468462

Cited by 34 publications

(11 citation statements)

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“…Hypodermic needles have been identified as convenient low-cost critical orifices to control flow rates. 7,8 The needles were re-used up to six times and checked for obstructions before being replaced.…”

Section: Sampling Methodsmentioning

confidence: 99%

Development of a unique multi-contaminant air sampling device for a childhood asthma cohort in an agricultural environment

Armstrong

Fitzpatrick

Loftus

et al. 2013

Environ. Sci.: Processes Impacts

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This research describes the design, deployment, performance, and acceptability of a novel outdoor active air sampler to provide simultaneous measurements of multiple contaminants at timed intervals for the Aggravating Factors of Asthma in Rural Environment (AFARE) study—a longitudinal cohort of 50 children in Yakima Valley, Washington. The sampler was constructed of multiple sampling media connected to individual critical orifices and a rotary vane vacuum pump. It was connected to a timed control valve system to collect 24 hours samples every six days over 18 months. We describe a spatially representative approach with both quantitative and qualitative location criteria to deploy a network of 14 devices at participant residences in a rural region (20 × 60 km). Overall the sampler performed well, as the concurrent mean sample flow rates were within or above the ranges of recommended sampling rates for each exposure metric of interest. Acceptability was high among the study population of Hispanic farmworker participant households. The sampler design may prove useful for future urban and rural community-based studies with aims at collecting multiple contaminant data during specific time periods.

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Section: Sampling Methodsmentioning

confidence: 99%

Development of a unique multi-contaminant air sampling device for a childhood asthma cohort in an agricultural environment

Armstrong

Fitzpatrick

Loftus

et al. 2013

Environ. Sci.: Processes Impacts

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“…and were constructed of nylon. The flow rate of air through the filters was controlled by hypodermic needles ( 6 ) and flow controllers (7).…”

Section: Methodsmentioning

confidence: 99%

Filter sampling method for atmospheric sulfur dioxide at background concentrations

Axelrod¹,

Hansen²

1975

Anal. Chem.

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0.2mM were stable and sufficiently concentrated to give quantitative results. The thiocyanate concentration was found to be important in driving the reaction to completion and affected the rate of complex formation. Low absorbances observed at concentrations less than about 0.2M might, in part, result from the decomposition of I(SCN)zto form the non-absorbing ISCN (IO).Hydrogen ion concentrations were about 1M in all cases.Lower concentrations caused a slight decrease in stability and higher concentrations (above 2-3M) led to the decomposition of thiocyanic acid (9).Absorbance measurements on thirty separately prepared solutions are shown in Table I. Precision of replicate measurements is good and the overall accuracy has a range of about f3%. A linear least squares fit to the data gives a slope of 41100 f 200 1. mol-' cm-l and a y-intercept of Possible interferences from extraneous ions were examined. Table I1 summarizes these observations. In each case, two solutions of identical iodide concentrations were compared with an extraneous ion added to one. These were carried through the procedure in parallel.Clearly, chloride presents no serious interference at the levels examined and bromide lowers the absorbance only a few percent. The fact that the chloride interference does not change with chloride concentration suggests that the 2% difference in absorbance may be a measurement error rather than an interference. Sulfate, a frequent interference in iodide analyses, causes a small decrease in absorbance.The transition metal ions interfered to varying extents. Since thiocyanate complexes form with these cations, interferences are to be expected.-0.003.

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“…by a critical orifice (hypodermic needle, Lodge, Pate, et al, 1966). The frits of the bubblers were checked frequently for pore size by the procedure described by Saltzman (1 969, particularly if low values of NO, were obtained.…”

Section: Methodsmentioning

confidence: 99%

Comparison of permeation devices and nitrite ion as standards for the colorimetric determination of nitrogen dioxide

Scaringelli¹,

Rosenberg²,

Rehme³

1970

Environ. Sci. Technol.

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The Use of Hypodermic Needles as Critical Orifices in Air Sampling

Cited by 34 publications

References 0 publications

Development of a unique multi-contaminant air sampling device for a childhood asthma cohort in an agricultural environment

Development of a unique multi-contaminant air sampling device for a childhood asthma cohort in an agricultural environment

Filter sampling method for atmospheric sulfur dioxide at background concentrations

Comparison of permeation devices and nitrite ion as standards for the colorimetric determination of nitrogen dioxide

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