scholarly journals Calibration and assessment of electrochemical low-cost sensors in remote alpine harsh environments

2021 ◽  
Vol 14 (9) ◽  
pp. 6005-6021
Author(s):  
Federico Dallo ◽  
Daniele Zannoni ◽  
Jacopo Gabrieli ◽  
Paolo Cristofanelli ◽  
Francescopiero Calzolari ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Limit Of Detection ◽  
Low Cost ◽  
Pearson Correlation ◽  
Eastern Alps ◽  
Limit Of Quantification ◽  
Atmospheric Sciences ◽  
Reference Instrument ◽  
Individual Calibration ◽  
Field Deployment

Abstract. This work presents results from an original open-source low-cost sensor (LCS) system developed to measure tropospheric O3 in a remote high altitude alpine site. Our study was conducted at the Col Margherita Observatory (2543 m above sea level), in the Italian Eastern Alps. The sensor system mounts three commercial low-cost O3/NO2 sensors that have been calibrated before field deployment against a laboratory standard (Thermo Scientific; 49i-PS), calibrated against the standard reference photometer no. 15 calibration scale of the World Meteorological Organization (WMO). Intra- and intercomparison between the sensors and a reference instrument (Thermo Scientific; 49c) have been conducted for 7 months from May to December 2018. The sensors required an individual calibration, both in laboratory and in the field. The sensor's dependence on the environmental meteorological variables has been considered and discussed. We showed that it is possible to reduce the bias of one LCS by using the average coefficient values of another LCS working in tandem, suggesting a way forward for the development of remote field calibration techniques. We showed that it is possible reconstruct the environmental ozone concentration during the loss of reference instrument data in situations caused by power outages. The evaluation of the analytical performances of this sensing system provides a limit of detection (LOD) <5 ppb (parts per billion), limit of quantification (LOQ) <17 ppb, linear dynamic range (LDR) up to 250 ppb, intra-Pearson correlation coefficient (PCC) up to 0.96, inter-PCC >0.8, bias >3.5 ppb and ±8.5 at 95 % confidence. This first implementation of a LCS system in an alpine remote location demonstrated how to obtain valuable data from a low-cost instrument in a remote environment, opening new perspectives for the adoption of low-cost sensor networks in atmospheric sciences.

scholarly journals Calibration and assessment of electrochemical low-cost sensors in remote alpine harsh environments

2021 ◽  
Author(s):  
Federico Dallo ◽  
Daniele Zannoni ◽  
Jacopo Gabrieli ◽  
Paolo Cristofanelli ◽  
Francescopiero Calzolari ◽  
...  
Keyword(s):  
High Altitude ◽  
Low Cost ◽  
Eastern Alps ◽  
Harsh Environments ◽  
Atmospheric Sciences ◽  
Valuable Data ◽  
Sensing System ◽  
Individual Calibration ◽  
Remote Environment ◽  
Field Deployment

Abstract. The present work presents the results obtained using an original open-source low-cost sensor (LCS) system developed to measure tropospheric O3 in a remote high altitude alpine site. We conducted our study at the Col Margherita Observatory (2543 m a.s.l.), a World Meteorological Organization Global Atmosphere Watch Regional Station, located in the Italian Eastern Alps. The sensing system mounts three equivalent commercial low-cost sensors that have been calibrated using a laboratory standard (Thermo 49iPS), referenced to the Standard Reference Photometer #15 calibration scale by the WMO, before field deployment. Intra and inter-comparison between sensors and reference (Thermo 49c) have been conducted for seven months from May to December 2018. The sensors required an individual calibration, both in laboratory and in the field. The sensor's dependence on the environmental meteorological variables has been considered and discussed. The evaluation of the analytical performances of this sensing system provides an LOD  3.5 ppb and ±8.5 at 95 % of confidence. Thanks to the first implementation of an LCS System in an alpine site, it has been demonstrated how it is possible to obtain valuable data from a low-cost instrument in a remote environment. This opens new perspectives for the adoption of a low-cost sensor network in atmospheric sciences.

UV-Visible Spectrophotometric Determination of Lambda-Cyhalothrin Insecticide in Vegetables, Soil and Water Samples

2019 ◽  
Vol 31 (1) ◽  
pp. 1-9
Author(s):  
Deepak Kumar Sahu ◽  
Joyce Rai ◽  
Chhaya Bhatt ◽  
Manish K. Rai ◽  
Jyoti Goswami ◽  
...  
Keyword(s):  
Crop Production ◽  
Limit Of Detection ◽  
Low Cost ◽  
Molar Absorptivity ◽  
Agricultural Field ◽  
Limit Of Quantification ◽  
Yellow Colour ◽  
Modern Age ◽  
Lambda Cyhalothrin

In modern age pesticide is used widely in agriculture. Lambda-cyhalothrin (LCT) is one of the most used pesticides which are used as a insecticide to kill pest, tricks, flies etc in agricultural field and it is also used for crop production. We have developed new method to detect LCT insecticide in agriculture field and reduce its uses. In this method we found the maximum absorbance at 460 nm for yellow colour dye. We also calculated limit of detection and limit of quantification 0.001 mg kg-1 and 0.056 mg kg-1 respectively. Molar absorptivity and Sandell’s sensitivity was also calculated and obtained 1.782 ×107 mol-1 cm-1 and 9.996 ×10-6 µg cm-2 respectively. The obtained yellow colour dye obeyed Beer’s law limit range of 0.5 µg ml -1 to 16 µg ml-1 in 25 ml. This method is less time consuming, selective, simple, sensitive and low cost. Present method is successfully applied in various soil, water and vegetable samples.

scholarly journals Development of Xpert® BCR-ABL Ultra, an Automated and Standardized Multiplex Assay with Required Performance Characteristics for BCR-ABL1 Quantitative Measurement on an International Reporting Scale

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2793-2793 ◽  
Author(s):  
Gwo-Jen Day ◽  
Christina Lockwood ◽  
Jacqueline E. Payton ◽  
Geoffrey L. Uy ◽  
Charles Schiffer ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Limit Of Detection ◽  
Standard Of Care ◽  
Acid Extraction ◽  
Analytical Sensitivity ◽  
Limit Of Quantification ◽  
Clinical Sensitivity ◽  
Real Time Quantitative Pcr ◽  
International Scale ◽  
Assess Treatment Response

Abstract Monitoring BCR-ABL transcript levels in patients on TKI therapy using real-time quantitative PCR is standard of care in the management of CML, and achieving sensitivity to 4.5 logs below baseline is important in patients being considered for TKI discontinuation. In order to accurately assess treatment response, it is essential to ensure that variability in testing methodologies is tightly controlled. This has resulted in substantial efforts to standardize BCR-ABL molecular measurement across laboratories by introducing an International Scale (IS). Here we describe the development and analytical evaluation of Xpert® BCR-ABL Ultra, an automated cartridge-based BCR-ABL monitoring assay incorporating lot-specific standardization to the International Scale as defined by WHO. The BCR-ABL Ultra cartridge simplifies the generation of highly accurate and reproducible assay results by integrating nucleic acid extraction, target amplification, and quantification of the BCR-ABL b3a2 or b2a2 transcripts relative to ABL in peripheral blood specimens. The assay turn-around-time is approximately 2.5 hours and has a %BCR-ABL/ABL(IS) dynamic range of ~6 logs, including two key milestones for the assessment of clinical response at ~10% (IS) (SD=~0.08Log) and ~0.0033% (IS) (SD=~0.25Log) (CMR4.5). Lot-to-lot standardization is achieved using a secondary standard panel of controls derived from and aligned to the first WHO international genetic reference panel. The secondary standards are produced at Cepheid as part of the assay kit manufacturing process and applied to every production lot of cartridges in order to improve assay reliability and reporting comparability. Analytical sensitivity studies using spiked-in CML cell lines demonstrated a limit of detection (LoD) and limit of quantification (LoQ) of 0.003% BCR-ABL/ABL (IS) with a limit of blank (LoB) of 0.00017%. In an analytical specificity study, assay results were negative in 100% of 70 known CML-negative samples, including 20 AML or ALL patients and 50 healthy donors. A study was further conducted to estimate the lower limit of clinical sensitivity using blood from 12 CML patients on TKI therapy who had achieved and maintained MMR with reporting below 0.05% (IS). Eleven out of twelve low CML subjects were detected in at least 19 out of 20 replicates tested per subject over a range of 0.038% (SD=~0.17Log) to 0.0011% (IS) (SD=~0.4Log). In conclusion, the Xpert BCR-ABL Ultra assay demonstrates sensitivity in the range necessary to make clinical decisions regarding the continuation of TKI therapy in patients achieving CMR4.5, and every production lot of cartridges is assigned a unique conversion factor guaranteeing alignment to the WHO International Scale. Disclosures Uy: Novartis: Research Funding.

scholarly journals Development and Application of a New QuEChERS Method in UHPLC-QqQ-MS/MS to Detect Seven Biogenic Amines in Chinese Wines

Foods ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 552
Author(s):  
Shun-Yu Han ◽  
Lan-Lan Hao ◽  
Xiao Shi ◽  
Jian-Ming Niu ◽  
Bo Zhang
Keyword(s):  
Biogenic Amines ◽  
Storage Time ◽  
Limit Of Detection ◽  
Pearson Correlation ◽  
High Sensitivity ◽  
Gansu Province ◽  
Grape Variety ◽  
Limit Of Quantification ◽  
Toxic Dose ◽  
Relative Standard

The aim of this study was to develop and validate an improved, simple, and sensitive method for the simultaneous determination of seven types (cadaverine, CAD; hexylamine, HEX; histamine, HIS; phenylethylamine, PEA; putrescine, PUT; tyramine, TYR) of biogenic amines (BAs) in wine matrices. For this reason, a modified QuEChERS combined with ultra-performance liquid chromatography coupled to a triple quadrupole mass spectrometry (UHPLC-QqQ-MS/MS) method was investigated. The optimization of UHPLC-QqQ-MS/MS separation and QuEChERS procedure was performed. Under optimum conditions, the excellent chromatographic performance of the whole separation was accomplished within 6.3 min analyzing time. Meanwhile, the recoveries ranged from 77.2% to 101.7%, while relative standard deviation (RSD) remained between 0.0% and 9.4%. The limit of detection (LOD, 0.50–1.00 µg/L) and the limit of quantification (LOQ, 1.65–3.30 µg/L) were lower than those permitted by legislation in food matrices, which demonstrated the high sensitivity and applicability of this efficient method. This validated method was also applied in a pilot study to analyze BAs in 81 wine samples from Hexi Corridor Region (Gansu Province, Northwest China), CAD, HEX, HIS, PEA, PUT, and TYR were detected to varying degrees in the samples. However, when compared with the existing standards, the BAs in all 81 wine samples did not exceed the prescribed limit value or toxic dose (2–40 mg/L). Moreover, a statistical approach was also conducted using Pearson correlation analysis, and to evaluate their concentrations in terms of wine parameters (storage time, grape variety, wine type, and basic physicochemical index). The results showed that, among the seven kinds of BAs, the concentration of HIS had a certain correlation with alcoholic degree and grape variety. In addition, the level of PEA had a certain correlation with the wine pH and wine storage time. It is worth noting that this seems to be the first report regarding the application of QuEChERS-UHPLC-QqQ-MS/MS in the analysis of BAs in wine in this region.

scholarly journals Determination of ?iroctone Olamine (Octopirox) in Bulk by UV Spectrophotometric Method

2017 ◽  
Vol 16 (1) ◽  
pp. 37-42
Author(s):  
Lyudmyla M Antypenko ◽  
Vitaliy A Solodovnyk
Keyword(s):  
Spectrophotometric Method ◽  
Limit Of Detection ◽  
Low Cost ◽  
Limit Of Quantification

A simple and low-cost UV-spectrophotometric method has been developed and validated for the quantification of Octopirox in bulk. The linearity was found at 307 ± 1 nm in 10-50 ?g/ml solution of ethanol-water (1:3, v:v) with r2 = 0.99. The limit of detection was found to be 1.18 µg/ml, while the limit of quantification was 3.58 µg/ml. The method was validated for linearity, accuracy, precision, range, ruggedness and robustness.Dhaka Univ. J. Pharm. Sci. 16(1): 37-42, 2017 (June)

scholarly journals Extraction of soluble sugars from green coffee beans using hot water and quantification by a chromatographic method without an organic solvent

2020 ◽  
Vol 32 (4) ◽  
pp. 242-246 ◽  
Author(s):  
Leonel Vinicius Constantino ◽  
Douglas Mariani Zeffa ◽  
Alessandra Koltun ◽  
Mariana Ragassi Urbano ◽  
Alisson Wilson Santos Sanzovo ◽  
...  
Keyword(s):  
High Performance ◽  
Chromatographic Method ◽  
Limit Of Detection ◽  
Low Cost ◽  
Soluble Sugar ◽  
Soluble Sugars ◽  
Hot Water ◽  
Green Coffee ◽  
Limit Of Quantification ◽  
Assisted Extraction

An optimal condition for extraction of soluble sugars from green coffee using water and a validated chromatographic method for its separation and quantification were proposed in this research. An orbital incubator shaker (OIS) and microwave-assisted extraction (MAE) were the 2 techniques used to extract soluble sugars. In such experiments, the variables: sample amount (300, 400, and 500 mg), time (30, 60, and 90 min), and temperature (30, 45, and 60 °C) were tested. The separation of sugars was performed in a chromatographic system (high-performance liquid chromatography refractive index detector [HPLC-RID]), which presented the selectivity for the analytes, a limit of detection of 0.020 g/L, a limit of quantification of 0.0625 g/L, and recovery rates greater than 95%. The repeatability and inter-day precision had low dispersion, RSD < 2.0% and < 3.0%, respectively. Sucrose content ranged from 0.65 to 2.39 g/L using an OIS and from 1.19 to 2.72 g/L by MAE, while glucose and fructose concentration varied from 0.08 to 0.12 g/L using both methods. The OIS technique is preferably indicated for extraction of soluble sugars at the following conditions: 500 mg of grounded green coffee, 90 min, and 60 °C. The proposed method for soluble sugar extraction and quantification may be applied in research laboratories and food industries since it is a low-cost and environment-friendly technique.

scholarly journals Development and Validation of a Reversed-Phase HPLC Method for the Estimation of Zolpidem in Bulk Drug and Tablets

2013 ◽  
Vol 2013 ◽  
pp. 1-6
Author(s):  
E. Konoz ◽  
A. H. Mohsen Sarrafi ◽  
R. Abdolahnejad ◽  
M. Bahrami-Zonoz
Keyword(s):  
High Performance ◽  
Dynamic Range ◽  
Limit Of Detection ◽  
Reversed Phase ◽  
Hplc Method ◽  
Control Analysis ◽  
Limit Of Quantification ◽  
Chromatography Method ◽  
Pharmaceutical Dosage Forms ◽  
Bulk Drug

In the present study an isocratic reversed-phase high-performance liquid chromatography method was developed for the estimation of zolpidem in bulk drug and pharmaceutical dosage forms. The quantification was carried out on C18columns. A mixture of acetonitrile-ammonium acetate (pH=8.0, 0.02 M) (60 : 40 v/v) was used as the mobile phase, at flow rate of 1.0 mL/min and the determination wavelength at 245 nm. The retention time of zolpidem was found to be 3–5 min. The validation of the proposed method was carried out for specificity, linearity, accuracy, precision, limit of detection, limit of quantification, and robustness. The linear dynamic range was from 2.5 to 30 μg mL−1. Regression equation was found to bey=0.1416x+0.0183with correlation coefficientr=0.9996. The percentage recovery obtained for zolpidem was greater than 96.5%. Limit of quantification and limit of detection were found to be 2.5 μg mL−1and 0.83 μg mL−1, respectively. The developed method can be used for routine quality control analysis of zolpidem in tablet formulations.

scholarly journals Determination of Methomyl Residue in Tobacco Samples by Heart-Cutting Two-Dimensional Liquid Chromatography with Tandem Mass Spectrometry

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Shihao Shen ◽  
Min Chen ◽  
Tiannan Wang ◽  
Ting Fei ◽  
Dianhai Yang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Dynamic Range ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
Tandem Mass ◽  
Two Dimensional ◽  
Retention Performance ◽  
Limit Of Quantification

A novel heart-cutting two-dimensional liquid chromatography coupled with tandem mass spectrometry (2D-LC-MS/MS) was developed for the qualitative and quantitative analysis of methomyl residue in tobacco. Compared to traditional methodologies, fairly high sensitivity and stability were achieved, and the sample procedure was simplified in the two-dimensional liquid chromatography (2D-LC) method. Although methomyl had poor retention performance in most of the reversed-phase liquid chromatography (RPLC) columns, an effective RP/RP strategy was successfully facilitated. An XB-Phenyl column was employed in the first dimension to effectively remove thousands of interference compounds in the matrix. In the second dimension, an ADME column was applied for further separation. After optimization of the separation conditions, a six-way valve was utilized for direct transformation of the target fraction from the 1st column to the 2nd column. A dynamic range of 2.5 ng/mL to 500 ng/mL was achieved with correlation coefficient (r2) greater than 0.9995. The limit of detection and limit of quantification were determined to be 0.69 and 2.30 ng/mL, respectively. The 2D-LC method shows high sensitivity, good reproducibility, and recovery for methomyl in tobacco samples. Therefore, the new method was quite suitable for routine analysis.

scholarly journals Ultra-low HIV-1 p24 detection limits with a bioelectronic sensor

2019 ◽  
Vol 412 (4) ◽  
pp. 811-818 ◽  
Author(s):  
Eleonora Macchia ◽  
Lucia Sarcina ◽  
Rosaria Anna Picca ◽  
Kyriaki Manoli ◽  
Cinzia Di Franco ◽  
...  
Keyword(s):  
Capsid Protein ◽  
Single Molecule ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Low Cost ◽  
Wide Field ◽  
Label Free ◽  
Limit Of Quantification ◽  
Great Relevance ◽  
Hiv 1

AbstractEarly diagnosis of the infection caused by human immunodeficiency virus type-1 (HIV-1) is vital to achieve efficient therapeutic treatment and limit the disease spreading when the viremia is at its highest level. To this end, a point-of-care HIV-1 detection carried out with label-free, low-cost, and ultra-sensitive screening technologies would be of great relevance. Herein, a label-free single molecule detection of HIV-1 p24 capsid protein with a large (wide-field) single-molecule transistor (SiMoT) sensor is proposed. The system is based on an electrolyte-gated field-effect transistor whose gate is bio-functionalized with the antibody against the HIV-1 p24 capsid protein. The device exhibits a limit of detection of a single protein and a limit of quantification in the 10 molecule range. This study paves the way for a low-cost technology that can quantify, with single-molecule precision, the transition of a biological organism from being “healthy” to being “diseased” by tracking a target biomarker. This can open to the possibility of performing the earliest possible diagnosis.

scholarly journals Cell-Free DNA in Pediatric Solid Organ Transplantation Using a New Detection Method of Separating Donor-Derived from Recipient Cell-Free DNA

2020 ◽  
Vol 66 (10) ◽  
pp. 1300-1309
Author(s):  
Evgenia Preka ◽  
Drew Ellershaw ◽  
Natalie Chandler ◽  
Helena Ahlfors ◽  
Helen Spencer ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Low Cost ◽  
Recipient Cell ◽  
Solid Organ Transplantation ◽  
Organ Transplant ◽  
Solid Organ ◽  
Nucleotide Polymorphisms ◽  
Limit Of Quantification ◽  
Cell Free Dna ◽  
Free Dna

Abstract Background The use of cell-free DNA (cfDNA) as a noninvasive biomarker to detect allograft damage is expanding rapidly. However, quantifying the low fraction of donor-derived cfDNA (ddcfDNA) is challenging and requires a highly sensitive technique. ddcfDNA detection through unique donor single nucleotide polymorphisms (SNPs) is a recent new approach, however there are limited data in pediatric solid organ transplant (SOT) recipients. Methods We developed an assay using a combination of 61 SNPs to quantify the ddcfDNA accurately using a custom R script to model for both the patient and donor genotypes requiring only a single sample from the allograft recipient. Performance of the assay was validated using genomic DNA (gDNA), cfDNA and donor samples where available. Results The R “genotype-free” method gave results comparable to when using the known donor genotype. applicable to both related and unrelated pairs and can reliably measure ddcfDNA (limit of blank, below 0.12%; limit of detection, above 0.25%; limit of quantification 0.5% resulting in 84% accuracy). 159 pediatric SOT recipients (kidney, heart, and lung) were tested without the need for donor genotyping. Serial sampling was obtained from 82 patients. Conclusion We have developed and validated a new assay to measure the fraction of ddcfDNA in the plasma of pediatric SOT recipients. Our method can be applicable in any donor-recipient pair without the need for donor genotyping and can provide results in 48 h at a low cost. Additional prospective studies are required to demonstrate its clinical validity in a large cohort of pediatric SOT recipients.

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