scholarly journals The Measurement of Intrapuff Nicotine Yield

1992 ◽  
Vol 15 (2) ◽  
pp. 75-86 ◽  
Author(s):  
EL Crooks ◽  
D Lynm
Keyword(s):  
Analytical Techniques ◽  
Total Activity ◽  
Total Radioactivity ◽  
Mainstream Smoke ◽  
Time Resolved ◽  
Cigarette Filter ◽  
Nicotine Concentration ◽  
Smoke Flow ◽  
A New Technique ◽  
Nicotine Yield

AbstractTime-resolved measurements of intrapuff nicotine yield in mainstream smoke have been performed with a specially designed intrapuff smoking apparatus (IPSA). The IPSA-filter traversing mechanism collects mainstream particles on a rectangular filter pad which moves at a constant velocity perpendicular to the direction of smoke flow at the mouthend of the cigarette. Filter pads were assayed by two analytical techniques. Standard gas chromatographic (GC) methodology was used to quantify nicotine mass in five equal time segments per puff. A second method, using a Berthold TLC-Linear Analyser, measured total radioactivity across the pad for samples from [2'-14C]-nicotine labelled cigarettes. Intrapuff nicotine concentrations were determined from measured puff flow-rate profiles and the collected masses of nicotine on the filters. GC nicotine concentration measurements correlated well with total activity from the scanner measurements. Studies carried out with filtered full-flavour cigarettes revealed that nicotine concentrations in the smoke vary significantly during a puff. This work provides a new technique for studying time-resolved yields of mainstream smoke components. It may potentially be used to elucidate mechanisms controlling the yield of nicotine and other mainstream smoke components.

scholarly journals An Analytical Perspective on Determination of Free Base Nicotine in E-Liquids

2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Vinit V. Gholap ◽  
Rodrigo S. Heyder ◽  
Leon Kosmider ◽  
Matthew S. Halquist
Keyword(s):  
Analytical Techniques ◽  
Liquid Extraction ◽  
Free Base ◽  
Extraction Solvent ◽  
Nicotine Concentration ◽  
H Nmr ◽  
Liquid Liquid Extraction ◽  
Comparative Results ◽  
Nicotine Yield

In electronic cigarette users, nicotine delivery to lungs depends on various factors. One of the important factors is e-liquid nicotine concentration. Nicotine concentration in e-liquids ranges from 0 to >50 mg/mL. Furthermore, nicotine exists in protonated and unprotonated (“free base”) forms. The two forms are believed to affect the nicotine absorption in body. Therefore, in addition to total nicotine concentration, e-liquids should be characterized for their free base nicotine yield. Two approaches are being used for the determination of free base nicotine in e-liquids. The first is applying a dilution to e-liquids followed by two methods: Henderson–Hasselbalch theory application or a Liquid-Liquid Extraction. The second is the without-dilution approach followed by 1H NMR method. Here, we carried out controlled experiments using five e-liquids of different flavors using these two approaches. In the dilution approach, the Henderson–Hasselbalch method was tested using potentiometric titration. The accuracy was found to be >98% for all five e-liquid samples (n = 3). A Liquid-Liquid Extraction was carried out using toluene or hexane as extraction solvent. The Liquid-Liquid Extraction technique was found to be limited by solvent interactions with flavors. Solvent extractions resulted in flavor dependent inaccuracies in free base nicotine determination (5 to 277% of calculated values). The without-dilution approach was carried out using 1H NMR as described by Duell et al. This approach is proposed to offer an independent and alternative scale. None of the methods have established a strong correlation between pre- and postvaporization free base nicotine yield. Here we present comparative results of two approaches using analytical techniques. Such a comparison would be helpful in establishing a standardized method for free base nicotine determination of e-liquids.

Electron Correlation Microscopy: A New Technique for Studying Local Atom Dynamics Applied to a Supercooled Liquid

2015 ◽  
Vol 21 (4) ◽  
pp. 1026-1033 ◽  
Author(s):  
Li He ◽  
Pei Zhang ◽  
Matthew F. Besser ◽  
Matthew Joseph Kramer ◽  
Paul M. Voyles
Keyword(s):  
Electron Correlation ◽  
Supercooled Liquid ◽  
Scanning Transmission Electron Microscope ◽  
Correlation Spectroscopy ◽  
New Technique ◽  
Time Resolved ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
A New Technique ◽  
Correlation Microscopy

AbstractElectron correlation microscopy (ECM) is a new technique that utilizes time-resolved coherent electron nanodiffraction to study dynamic atomic rearrangements in materials. It is the electron scattering equivalent of photon correlation spectroscopy with the added advantage of nanometer-scale spatial resolution. We have applied ECM to a Pd40Ni40P20 metallic glass, heated inside a scanning transmission electron microscope into a supercooled liquid to measure the structural relaxation time τ between the glass transition temperature Tg and the crystallization temperature, Tx. τ determined from the mean diffraction intensity autocorrelation function g2(t) decreases with temperature following an Arrhenius relationship between Tg and Tg+25 K, and then increases as temperature approaches Tx. The distribution of τ determined from the g2(t) of single speckles is broad and changes significantly with temperature.

scholarly journals Metabolism of the nucleic acids of rumen bacteria by preruminant and ruminant lambs

1981 ◽  
Vol 45 (3) ◽  
pp. 517-527 ◽  
Author(s):  
M. A. Razzaque ◽  
J. H. Topps ◽  
R. N. B. Kay ◽  
J. M. Brockway
Keyword(s):  
Nucleic Acids ◽  
Bacterial Culture ◽  
Total Activity ◽  
Total Radioactivity ◽  
The Other ◽  
Nucleic Acid Content ◽  
Rumen Bacteria ◽  
Total Nucleic Acid ◽  
Purine Base ◽  
Close Relationship

1. A rumen bacterial culture containing specifically labelled nucleic acids was prepared using [8-14C]adenine.2. The labelled preparation was given in a liquid diet to two preruminant lambs and via a rumen tube to two ruminant lambs. The radioactivity excreted in exhaled gases, faeces and urine and that incorporated into tissues was determined.3 The preruminant lambs absorbed 58.3% of the total radioactivity measured after 24 h and the ruminant lambs 66.6% of the total activity measured after 48 h.4. Of the total radioactivity absorbed the preruminant lambs exhaled 38%, excreted 34% in urine and retained 29% in tissues. The corresponding values for the ruminant lambs were 12,41 and 47% respectively.5. There was a close relationship between total nucleic acid content and radioactivity per g of tissues of both preruminant and ruminant lambs.6. Of the radioactivity in the urine, the ruminant and one preruminant lamb excreted most in the fraction containing allantoin, while the other lamb excreted most activity in the uric acid fraction.7. The salvaging of the breakdown products of bacterial nucleic acids to make tissue nucleic acids appears to be an important synthesis in preruminant and ruminant lambs and of the likely precursors the purine base may be more important than the nucleoside.

scholarly journals Pressure and Gas Flow Distribution Inside the Filter of a Non-Filter Ventilated Lit Cigarette During Puffing

2017 ◽  
Vol 27 (6) ◽  
pp. 113-124
Author(s):  
Bin Li ◽  
Xiaomeng Cui ◽  
Lucan Zhao ◽  
Le Wang ◽  
Guoyong Xie ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Gas Flow ◽  
Flow Direction ◽  
Flow Distribution ◽  
Mainstream Smoke ◽  
Cigarette Filter ◽  
Spatially Resolved ◽  
Dynamic Filtration ◽  
Temperature And Pressure ◽  
Burning Coal

SummaryEstablishing a realistic gas flow velocity distribution inside a cigarette filter during smoking is important to understand filtration mechanisms of different mainstream smoke species and the overall effect of filter designs on mainstream smoke composition. In this paper, an experimental method is described which directly measures the gas pressure field inside a cellulose acetate filter during cigarette smoking. This was demonstrated by using 3R4F research reference cigarettes smoked under a 35 mL puff of 6 s duration. In addition, filter temperature measurements were also carried out at multiple locations within the filter. Both the temperature and pressure sensing locations were selected to match the radial and longitudinal directions of the cigarette filter. The temperature and pressure measurements were then used to calculate the velocity according to Darcy’s Law along the mainstream flow direction in the cigarette filter at each puff. The spatially resolved maps of temperature, pressure and flow velocity on a puff-by-puff basis provide useful insights into the dynamic filtration of smoke aerosol under the influence of the approaching burning coal and progressive accumulation of smoke particulate matter.

scholarly journals Uranium Speciation and Bioavailability in Aquatic Systems: An Overview

2002 ◽  
Vol 2 ◽  
pp. 707-729 ◽  
Author(s):  
Scott J. Markich
Keyword(s):  
Surface Waters ◽  
Metal Ion ◽  
Natural Waters ◽  
Analytical Techniques ◽  
Time Resolved ◽  
Analytical Technique ◽  
Major Form ◽  
Uranyl Carbonate ◽  
Inorganic Ligands ◽  
The Relationship

The speciation of uranium (U) in relation to its bioavailability is reviewed for surface waters (fresh- and seawater) and their sediments. A summary of available analytical and modeling techniques for determining U speciation is also presented. U(VI) is the major form of U in oxic surface waters, while U(IV) is the major form in anoxic waters. The bioavailability of U (i.e., its ability to bind to or traverse the cell surface of an organism) is dependent on its speciation, or physicochemical form. U occurs in surface waters in a variety of physicochemical forms, including the free metal ion (U4+or UO22+) and complexes with inorganic ligands (e.g., uranyl carbonate or uranyl phosphate), and humic substances (HS) (e.g., uranyl fulvate) in dissolved, colloidal, and/or particulate forms. Although the relationship between U speciation and bioavailability is complex, there is reasonable evidence to indicate that UO22+and UO2OH+are the major forms of U(VI) available to organisms, rather than U in strong complexes (e.g., uranyl fulvate) or adsorbed to colloidal and/or particulate matter. U(VI) complexes with inorganic ligands (e.g., carbonate or phosphate) and HS apparently reduce the bioavailability of U by reducing the activity of UO22+and UO2OH+. The majority of studies have used the results from thermodynamic speciation modeling to support these conclusions. Time-resolved laser-induced fluorescence spectroscopy is the only analytical technique able to directly determine specific U species, but is limited in use to freshwaters of low pH and ionic strength. Nearly all of the available information relating the speciation of U to its bioavailability has been derived using simple, chemically defined experimental freshwaters, rather than natural waters. No data are available for estuarine or seawater. Furthermore, there are no available data on the relationship between U speciation and bioavailability in sediments. An understanding of this relationship has been hindered due to the lack of direct quantitative U speciation techniques for particulate phases. More robust analytical techniques for determining the speciation of U in natural surface waters are needed before the relationship between U speciation and bioavailability can be clarified.

Assessment of the Emerging Technologies for the Detection and Measurement of Corrosion Wastage of Coated Marine Structures

2003 ◽  
Author(s):  
Sittha Saidarasamoot ◽  
David L. Olson ◽  
Brajendra Mishra ◽  
John S. Spencer ◽  
Ge Wang
Keyword(s):  
Structural Integrity ◽  
Electrochemical Sensors ◽  
Emerging Technologies ◽  
Rapid Determination ◽  
Sensor Arrays ◽  
Analytical Techniques ◽  
Offshore Structures ◽  
Marine Structures ◽  
Marine Corrosion ◽  
Time Resolved

The application of a resistant coating on ships, offshore structures and pipelines is the primary prevention method of corrosion wastage in the marine industries. To guarantee coating integrity and to be able to thoroughly survey for corrosion wastage on marine structures, new advanced nondestructive methods are being sought. The requirements of convenient and rapid determination of corrosion wastage on coated structures, even in the difficult spatial positions of the structure, will require advanced technologies which are being developed for other industries that also require very high structural integrity. A review of the developments in electromagnetic wave (advanced microwave and eddy current practices) sensors, in elastic wave (advanced ultrasonic practices) sensors, in time-resolved thermography (thermal imaging), in electrochemical sensors and in other emerging analytical techniques is presented. Each of the identified emerging technologies was assessed based on a set of requirements necessary to be an acceptable marine corrosion wastage testing tool. This technology review and assessment include the use of both active and passive sensors and monitors, and the use of sensor arrays. The state of development and availability of the most promising technologies will be described.

Estimating smokers' mouth-level exposure to select mainstream smoke constituents from discarded cigarette filter butts

2009 ◽  
Vol 11 (7) ◽  
pp. 868-874 ◽  
Author(s):  
Gregory M. Polzin ◽  
Weijia Wu ◽  
Xizheng Yan ◽  
Joan M. McCraw ◽  
Shadeed Abdul-Salaam ◽  
...  
Keyword(s):  
Mainstream Smoke ◽  
Cigarette Filter

scholarly journals Robustness of HPHC Reduction for THS 2.2 Aerosol Compared with 3R4F Reference Cigarette Smoke Under High Intensity Puffing Conditions

2020 ◽  
Vol 29 (2) ◽  
pp. 66-83
Author(s):  
Catherine Goujon ◽  
Samuel Kleinhans ◽  
Serge Maeder ◽  
Laurent Poget ◽  
Jean-Pierre Schaller
Keyword(s):  
Cigarette Smoke ◽  
High Intensity ◽  
Large Range ◽  
Tobacco Product ◽  
Mainstream Smoke ◽  
Cigarette Filter ◽  
Puff Volume ◽  
Multiple Regimes ◽  
Present Context ◽  
Health Canada

SummaryIn the absence of standards specific for testing the reduction robustness of the levels of harmful and potentially harmful constituents (HPHCs), the aerosol from the THS 2.2, a heated tobacco product, was compared with the mainstream smoke of the 3R4F reference cigarette over a broad range of machine-smoking regimes. The average reduction and the introduced concept of threshold limits of robust reduction were derived from HPHC concentrations, in mass per tobacco-stick normalized per total puff volume, to propose an alternative for the assessment of products where nicotine-adjusted yields would be inappropriate. In addition, this study explores the influence of 3R4F reference cigarette filter ventilation, and discusses the roles of temperature and precursors in the present context of robustness of HPHC reduction. Fifty-four HPHCs were analyzed under multiple regimes in THS 2.2 aerosol and 3R4F cigarette smoke. The average reduction of HPHC concentrations compared across all regimes characterized the robustness. Threshold limits of reduction of individual HPHCs were statistically determined across all regimes. The results observed under Health Canada Intense (HCI) and more intense regimes indicated that on average the reductions in HPHCs levels investigated in THS 2.2 aerosol were more than 90% and that the majority of the 54 HPHCs investigated in THS 2.2 aerosol showed more than 90% reduction. The robustness of THS 2.2 in maintaining the levels of reduction of representative HPHCs, whatever the puffing regime, can be quantified. The mass of HPHC per tobacco-stick normalized per total puff volume is a valuable approach to compare the robustness of the performance of a product over a large range of puffing conditions. Our findings will greatly complement the assessment for robustness of current and future similar products where classical approaches would present limitations.

scholarly journals An Electronic Aerosol Delivery System for Functional Magnetic Resonance Imaging

2020 ◽  
Vol 14 ◽  
pp. 117822182090414
Author(s):  
Andréa L Hobkirk ◽  
Zachary Bitzer ◽  
Reema Goel ◽  
Christopher T Sica ◽  
Craig Livelsberger ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Free Radical ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Free Radical Production ◽  
Nicotine Concentration ◽  
Radical Production ◽  
Addictive Potential ◽  
Nicotine Yield

Background: Public health concerns over the addictive potential of electronic cigarettes (e-cigs) have heightened in recent years. Brain function during e-cig use could provide an objective measure of the addictive potential of new vaping products to facilitate research; however, there are limited methods for delivering e-cig aerosols during functional magnetic resonance imaging (fMRI). The current study describes the development and feasibility testing of a prototype to deliver up to four different e-cig aerosols during fMRI. Methods: Standardized methods were used to test the devices’ air flow variability, nicotine yield, and free radical production. MRI scans were run with and without the device present to assess its safety and effects on MRI data quality. Five daily smokers were recruited to assess plasma nicotine absorption from e-liquids containing nicotine concentrations of 8, 11, 16, 24, and 36 mg/ml. Feedback was collected from participants through a semi-structured interview and computerized questionnaire to assess comfort and subjective experiences of inhaling aerosol from the device. Results: Nicotine yield captured from the aerosol produced by the device was highly correlated with the nicotine concentration of the e-liquids used (R2 = 0.965). Nicotine yield was reduced by a mean of 48% and free radical production by 17% after traveling through the device. The e-liquid containing the highest nicotine concentration tested (36 mg/ml) resulted in the highest plasma nicotine boost (6.6 ng/ml). Overall, participants reported that the device was comfortable to use and inhaling the e-cig aerosols was tolerable. The device was determined to be safe for use during fMRI and had insignificant effects on scan quality. Conclusions: With the current project, we were able to design a working prototype that safely and effectively delivers e-cig aerosols during fMRI. The device has the potential to be used to assess brain activation during e-cig use and to compare brain reactivity to varying flavors, nicotine concentrations, and other e-cig characteristics.

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