scholarly journals iDirac: a field-portable instrument for long-term autonomous measurements of isoprene and selected VOCs

2020 ◽  
Vol 13 (2) ◽  
pp. 821-838 ◽  
Author(s):  
Conor G. Bolas ◽  
Valerio Ferracci ◽  
Andrew D. Robinson ◽  
Mohammed I. Mead ◽  
Mohd Shahrul Mohd Nadzir ◽  
...  
Keyword(s):  
Power Efficiency ◽  
Modular Design ◽  
Limit Of Detection ◽  
The Novel ◽  
Relative Standard ◽  
New Instrument ◽  
Instrument Control ◽  
Gas Consumption ◽  
And Performance ◽  
Dual Column

Abstract. The iDirac is a new instrument to measure selected hydrocarbons in the remote atmosphere. A robust design is central to its specifications, with portability, power efficiency, low gas consumption and autonomy as the other driving factors in the instrument development. The iDirac is a dual-column isothermal oven gas chromatograph with photoionisation detection (GC-PID). The instrument is designed and built in-house. It features a modular design, with the novel use of open-source technology for accurate instrument control. Currently configured to measure biogenic isoprene, the system is suitable for a range of compounds. For isoprene measurements in the field, the instrument precision (relative standard deviation) is ±10 %, with a limit of detection down to 38 pmol mol−1 (or ppt). The instrument was first tested in the field in 2015 during a ground-based campaign, and has since shown itself suitable for deployment in a variety of environments and platforms. This paper describes the instrument design, operation and performance based on laboratory tests in a controlled environment as well as during deployments in forests in Malaysian Borneo and central England.

scholarly journals iDirac: a field-portable instrument for long-term autonomous measurements of isoprene and selected VOCs

2019 ◽  
Author(s):  
Conor G. Bolas ◽  
Valerio Ferracci ◽  
Andrew D. Robinson ◽  
Mohamad I. Mead ◽  
Mohd Shahrul Mohd Nadzir ◽  
...  
Keyword(s):  
Power Efficiency ◽  
Modular Design ◽  
Limit Of Detection ◽  
Relative Standard ◽  
New Instrument ◽  
Instrument Control ◽  
Gas Consumption ◽  
And Performance ◽  
Dual Column

Abstract. The iDirac is a new instrument to measure selected hydrocarbons in the remote atmosphere. A robust design is central to its specifications, with portability, power efficiency, low gas consumption and autonomy as the other driving factors in the instrument development. The iDirac is a dual-column isothermal oven gas chromatograph with photoionisation detection (GC-PID). The instrument is designed and built in-house. It features a modular design, with novel use of open-source technology for accurate instrument control. Currently configured to measure biogenic isoprene, the system is suitable for a range of compounds. For isoprene measurements in the field, the instrument precision (relative standard deviation) is ± 11 %, with a limit of detection down to 38 pmol mol−1 (or ppt). The instrument was first tested in the field in 2015 in a ground-based campaign, and has since shown itself suitable for deployment in a variety of environments and platforms. This paper describes the instrument design, operation and performance based on laboratory tests in a controlled environment, and during deployments in forests in Malaysian Borneo and in Central England.

scholarly journals <i>μ</i>Dirac: an autonomous instrument for halocarbon measurements

2010 ◽  
Vol 3 (2) ◽  
pp. 507-521 ◽  
Author(s):  
B. Gostlow ◽  
A. D. Robinson ◽  
N. R. P. Harris ◽  
L. M. O'Brien ◽  
D. E. Oram ◽  
...  
Keyword(s):  
Power Efficiency ◽  
Anthropogenic Sources ◽  
Gas Chromatograph ◽  
Critical Design ◽  
Long Duration ◽  
Relative Standard ◽  
New Instrument ◽  
Design Requirements ◽  
Temperature Programmed ◽  
Prototype Instrument

Abstract. We describe a new instrument (μDirac) capable of measuring halocarbons in the atmosphere. Portability, power efficiency and autonomy were critical design requirements and the resulting instrument can be readily deployed unattended on a range of platforms: long duration balloon, aircraft, ship and ground-based stations. The instrument is a temperature programmed gas chromatograph with electron capture detector (GC-ECD). The design requirements led to μDirac being built in-house with several novel features. It currently measures a range of halocarbons (including short-lived tracers having biogenic and anthropogenic sources) with measurement precision relative standard deviations ranging from ± 1% (CCl4) to ± 9% (CH3I). The prototype instrument was first tested in 2005 and the instrument has been proved in the field on technically challenging aircraft and ground-based campaigns. Results from an aircraft and a ground-based deployment are described.

Calcium/Copper alginate framework doped with CuO nano-particles as a novel adsorbent for micro-extraction of benzodiazepines from human serum

2020 ◽  
Vol 16 ◽  
Author(s):  
Nadereh Rahbar ◽  
Fatemeh Ahmadi ◽  
Zahra Ramezani ◽  
Masoumeh Nourani
Keyword(s):  
Human Serum ◽  
High Performance ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Nano Particles ◽  
Limit Of Quantification ◽  
Analytical Methodology ◽  
Fiber Fabrication ◽  
Relative Standard ◽  
Green Procedure

Background: Sample preparation is one of the most challenging phases in pharmaceutical analysis, especially in biological matrices, affecting the whole analytical methodology. Objective: In this study, a new Ca(II)/Cu(II)/alginate/CuO nanoparticles hydrogel fiber (CCACHF) was synthesized through a simple, green procedure and applied for fiber micro solid phase extraction (FMSPE) of diazepam (DIZ) and oxazepam (OXZ) as model drugs prior to high-performance liquid chromatography-UV detection (HPLC-UV). Methods: Composition and morphology of the prepared fiber were characterized and the effect of main parameters on the fiber fabrication and extraction efficiency have been studied and optimized. Results: In optimal conditions, calibration curves were linear ranging between 0.1–500 µg L−1 with regression coefficients of 0.9938 and 0.9968. Limit of detection (LOD) (S/N=3) and limit of quantification (LOQ) (S/N=10) of the technique for DIZ and OXZ were 0.03 to 0.1 µg L−1. Within-day and between-day relative standard deviations (RSDs) for DIZ and OXZ were 6.0–12.5% and 3.3–9.4%, respectively. Conclusion: The fabricated adsorbent has been substantially employed to extraction of selected benzo-diazepines (BZDs) from human serum real specimens and the obtained recoveries were also satisfactory (82.1-109.7%).

scholarly journals A verified genomic reference sample for assessing performance of cancer panels detecting small variants of low allele frequency

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Wendell Jones ◽  
Binsheng Gong ◽  
Natalia Novoradovskaya ◽  
Dan Li ◽  
Rebecca Kusko ◽  
...  
Keyword(s):  
Quality Control ◽  
Allele Frequency ◽  
Liquid Biopsy ◽  
Limit Of Detection ◽  
Reference Sample ◽  
Digital Pcr ◽  
Detection Sensitivity ◽  
Analytical Accuracy ◽  
And Performance ◽  
Reference Samples

Abstract Background Oncopanel genomic testing, which identifies important somatic variants, is increasingly common in medical practice and especially in clinical trials. Currently, there is a paucity of reliable genomic reference samples having a suitably large number of pre-identified variants for properly assessing oncopanel assay analytical quality and performance. The FDA-led Sequencing and Quality Control Phase 2 (SEQC2) consortium analyze ten diverse cancer cell lines individually and their pool, termed Sample A, to develop a reference sample with suitably large numbers of coding positions with known (variant) positives and negatives for properly evaluating oncopanel analytical performance. Results In reference Sample A, we identify more than 40,000 variants down to 1% allele frequency with more than 25,000 variants having less than 20% allele frequency with 1653 variants in COSMIC-related genes. This is 5–100× more than existing commercially available samples. We also identify an unprecedented number of negative positions in coding regions, allowing statistical rigor in assessing limit-of-detection, sensitivity, and precision. Over 300 loci are randomly selected and independently verified via droplet digital PCR with 100% concordance. Agilent normal reference Sample B can be admixed with Sample A to create new samples with a similar number of known variants at much lower allele frequency than what exists in Sample A natively, including known variants having allele frequency of 0.02%, a range suitable for assessing liquid biopsy panels. Conclusion These new reference samples and their admixtures provide superior capability for performing oncopanel quality control, analytical accuracy, and validation for small to large oncopanels and liquid biopsy assays.

scholarly journals A modular design method based on TRIZ and AD and its application to cutter changing robot

2021 ◽  
Vol 13 (7) ◽  
pp. 168781402110343
Author(s):  
Mei Yang ◽  
Yimin Xia ◽  
Lianhui Jia ◽  
Dujuan Wang ◽  
Zhiyong Ji
Keyword(s):  
Modular Design ◽  
Design Method ◽  
Idea Generation ◽  
Design Parameters ◽  
Problem Analysis ◽  
Concept Design ◽  
Functional Requirements ◽  
Shield Tunneling ◽  
Structural Hierarchy ◽  
And Performance

Modular design, Axiomatic design (AD) and Theory of inventive problem solving (TRIZ) have been increasingly popularized in concept design of modern mechanical product. Each method has their own advantages and drawbacks. The benefit of modular design is reducing the product design period, and AD has the capability of problem analysis, while TRIZ’s expertise is innovative idea generation. According to the complementarity of these three approaches, an innovative and systematic methodology is proposed to design big complex mechanical system. Firstly, the module partition is executed based on scenario decomposition. Then, the behavior attributes of modules are listed to find the design contradiction, including motion form, spatial constraints, and performance requirements. TRIZ tools are employed to deal with the contradictions between behavior attributes. The decomposition and mapping of functional requirements and design parameters are carried out to construct the structural hierarchy of each module. Then, modules are integrated considering the connections between each other. Finally, the operation steps in application scenario are designed in temporal and spatial dimensions. Design of cutter changing robot for shield tunneling machine is taken as an example to validate the feasibility and effectiveness of the proposed method.

scholarly journals A GPR-Based Pavement Density Profiler: Operating Principles and Applications

2021 ◽  
Vol 13 (13) ◽  
pp. 2613
Author(s):  
Nectaria Diamanti ◽  
A. Peter Annan ◽  
Steven R. Jackson ◽  
Dylan Klazinga
Keyword(s):  
Asphalt Pavement ◽  
Wave Impedance ◽  
Asphalt Mixtures ◽  
Void Content ◽  
Air Voids ◽  
New Instrument ◽  
Pavement Engineering ◽  
And Performance ◽  
Air Void ◽  
Air Void Content

Density is one of the most important parameters in the construction of asphalt mixtures and pavement engineering. When a mixture is properly designed and compacted, it will contain enough air voids to prevent plastic deformation but will have low enough air void content to prevent water ingress and moisture damage. By mapping asphalt pavement density, areas with air void content outside of the acceptable range can be identified to predict its future life and performance. We describe a new instrument, the pavement density profiler (PDP) that has evolved from many years of making measurements of asphalt pavement properties. This instrument measures the electromagnetic (EM) wave impedance to infer the asphalt pavement density (or air void content) locally and over profiles.

scholarly journals Stability-indicating HPLC-DAD assay for simultaneous quantification of hydrocortisone 21 acetate, dexamethasone, and fluocinolone acetonide in cosmetics

2020 ◽  
Vol 18 (1) ◽  
pp. 962-973
Author(s):  
Saira Arif ◽  
Sadia Ata
Keyword(s):  
Mobile Phase ◽  
Limit Of Detection ◽  
Fluocinolone Acetonide ◽  
Internal Diameter ◽  
Forced Degradation ◽  
Specific Method ◽  
Regression Equations ◽  
Limit Of Quantification ◽  
Simultaneous Quantification ◽  
Relative Standard

AbstractA rapid and specific method was developed for simultaneous quantification of hydrocortisone 21 acetate (HCA), dexamethasone (DEX), and fluocinolone acetonide (FCA) in whitening cream formulations using reversed-phase high-performance liquid chromatography. The effect of the composition of the mobile phase, analysis temperature, and detection wavelength was investigated to optimize the separation of studied components. The analytes were finally well separated using ACE Excel 2, C18 AR column having 150 mm length, 3 mm internal diameter, and 2 µm particle size at 35°C using methanol with 1% formic acid and double-distilled deionized water in the ratio of 60:40 (v/v), respectively, as the mobile phase in isocratic mode. Ten microliters of sample were injected with a flow rate of 0.5 mL/min. The specificity, linearity, accuracy, precision, recovery, limit of detection (LOD), limit of quantification (LOQ), and robustness were determined to validate the method as per International Conference on Harmonization guidelines. All the analytes were simultaneously separated within 8 min, and observed retention times of HCA, DEX, and FCA were 4.5, 5.5, and 6.9 min, respectively. The proposed method showed good linearity with the correlation coefficient, R2 = 0.999 over the range of 1–150 µg/mL for all standards. The linear regression equations were y = 12.7x + 118.7 (r = 0.999) for HCA, y = 12.9x + 106.8 (r = 0.999) for DEX, and y = 12.9x + 96.8 (r = 0.999) for FCA. The LOD was 0.25, 0.20, and 0.08 µg/mL for HCA, FCA, and DEX and LOQ was 2.06, 1.83, and 1.55 µg/mL for HCA, FCA, and DEX, respectively. The recovery values of HCA, DEX, and FCA ranged from 100.7–101.3, 102.0–102.6, and 100.2–102.0%, respectively, and the relative standard deviation for precision (intra- and interday) was less than 2, which indicated repeatability and reproducibility. The novelty of the method was described by forced degradation experimentation of all analytes in the combined form under acidic, basic, oxidative, and thermal stress. The proposed method was found to be simple, rapid, and reliable for the simultaneous determination of HCA, DEX, and FCA in cosmetics.

scholarly journals Does Hyperoxia Restrict Pyrenean Rock Lizards Iberolacerta bonnali to High Elevations?

Diversity ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 200
Author(s):  
Eric J. Gangloff ◽  
Sierra Spears ◽  
Laura Kouyoumdjian ◽  
Ciara Pettit ◽  
Fabien Aubret
Keyword(s):  
High Elevation ◽  
Conservation Strategy ◽  
The Novel ◽  
Thermal Physiology ◽  
Treatment Groups ◽  
Thermal Performance Curve ◽  
And Performance ◽  
Thermal Preferences ◽  
High Elevations ◽  
Intense Radiation

Ectothermic animals living at high elevation often face interacting challenges, including temperature extremes, intense radiation, and hypoxia. While high-elevation specialists have developed strategies to withstand these constraints, the factors preventing downslope migration are not always well understood. As mean temperatures continue to rise and climate patterns become more extreme, such translocation may be a viable conservation strategy for some populations or species, yet the effects of novel conditions, such as relative hyperoxia, have not been well characterised. Our study examines the effect of downslope translocation on ectothermic thermal physiology and performance in Pyrenean rock lizards (Iberolacerta bonnali) from high elevation (2254 m above sea level). Specifically, we tested whether models of organismal performance developed from low-elevation species facing oxygen restriction (e.g., hierarchical mechanisms of thermal limitation hypothesis) can be applied to the opposite scenario, when high-elevation organisms face hyperoxia. Lizards were split into two treatment groups: one group was maintained at a high elevation (2877 m ASL) and the other group was transplanted to low elevation (432 m ASL). In support of hyperoxia representing a constraint, we found that lizards transplanted to the novel oxygen environment of low elevation exhibited decreased thermal preferences and that the thermal performance curve for sprint speed shifted, resulting in lower performance at high body temperatures. While the effects of hypoxia on thermal physiology are well-explored, few studies have examined the effects of hyperoxia in an ecological context. Our study suggests that high-elevation specialists may be hindered in such novel oxygen environments and thus constrained in their capacity for downslope migration.

scholarly journals A novel LC-MS method development and validation for the determination of phenyl vinyl sulfone in eletriptan hydrobromide

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Indhu Priya Mabbu ◽  
G. Sumathi ◽  
N. Devanna
Keyword(s):  
Method Development ◽  
Limit Of Detection ◽  
Vinyl Sulfone ◽  
Limit Of Quantification ◽  
Relative Standard ◽  
Pressure Chemical Ionization ◽  
Pressure Chemical ◽  
Development And Validation ◽  
Phenyl Vinyl

Abstract Background The aim of the present method is to develop and validate a specific, sensitive, precise, and accurate liquid chromatography-mass spectrometry (LC-MS) method for the estimation of the phenyl vinyl sulfone in the eletriptan hydrobromide. The effective separation of the phenyl vinyl sulfone was achieved by the Symmetry C18 (50 × 4.6 mm, 3.5 μm) column and a mobile phase composition of 0.1%v/v ammonia buffer to methanol (5:95 v/v), using 0.45 ml/min flow rate and 20 μl of injection volume, with methanol used as diluent. The phenyl vinyl sulfone was monitored on atomic pressure chemical ionization mode mass spectrometer with positive polarity mode. Results The retention time of phenyl vinyl sulfone was found at 2.13 min. The limit of detection (LOD) and limit of quantification (LOQ) were observed at 1.43 ppm and 4.77 ppm concentration respectively; the linear range was found in the concentration ranges from 4.77 to 27.00 ppm with regression coefficient of 0.9990 and accuracy in the range of 97.50–102.10%. The percentage relative standard deviation (% RSD) for six replicates said to be injections were less than 10%. Conclusion The proposed method was validated successfully as per ICH guidelines. Hence, this is employed for the determination of phenyl vinyl sulfone in the eletriptan hydrobromide.

scholarly journals A highly sensitive octopus-like azobenzene fluorescent probe for determination of abamectin B1 in apples

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhenlong Guo ◽  
YiFei Su ◽  
Kexin Li ◽  
MengYi Tang ◽  
Qiang Li ◽  
...  
Keyword(s):  
Fluorescent Probe ◽  
Limit Of Detection ◽  
Quantitative Detection ◽  
Fluorescence Signal ◽  
Ionization Mass ◽  
Limit Of Quantification ◽  
Visible Absorption ◽  
Esi Ms ◽  
Relative Standard ◽  
Ft Ir

AbstractThe development of detecting residual level of abamectin B1 in apples is of great importance to public health. Herein, we synthesized a octopus-like azobenzene fluorescent probe 1,3,5-tris (5′-[(E)-(p-phenoxyazo) diazenyl)] benzene-1,3-dicarboxylic acid) benzene (TPB) for preliminary detection of abamectin B1 in apples. The TPB molecule has been characterized by ultraviolet–visible absorption spectrometry, 1H-nuclear magnetic resonance, fourier-transform infrared (FT-IR), electrospray ionization mass spectroscopy (ESI-MS) and fluorescent spectra. A proper determination condition was optimized, with limit of detection and limit of quantification of 1.3 µg L−1 and 4.4 μg L−1, respectively. The mechanism of this probe to identify abamectin B1 was illustrated in terms of undergoing aromatic nucleophilic substitution, by comparing fluorescence changes, FT-IR and ESI-MS. Furthermore, a facile quantitative detection of the residual abamectin B1 in apples was achieved. Good reproducibility was present based on relative standard deviation of 2.2%. Six carboxyl recognition sites, three azo groups and unique fluorescence signal towards abamectin B1 of this fluorescent probe demonstrated reasonable sensitivity, specificity and selectivity. The results indicate that the octopus-like azobenzene fluorescent probe can be expected to be reliable for evaluating abamectin B1 in agricultural foods.

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