Seven-Rod Dielectric Sensor for Determination of Soil Moisture in Small Volumes

The paper presents the performance of a seven-rod dielectric probe for determination of soil dielectric permittivity using FEM simulations as well as FDR and TDR measurements. The volume of the sensitivity zone of the tested probe was assessed basing on the simulations and measurement in liquids. The probe was also tested in two soils, sandy loam and silt loam. The obtained results suggested that the seven-rod probe can be used to accurately measure the dielectric permittivity spectrum in a small sample volume of about 8 cm3 in a frequency range from 20 MHz to 200 MHz.

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A Seven-Rod Dielectric Sensor for Determination of Soil Moisture in Well-Defined Sample Volumes

Sensors ◽

10.3390/s19071646 ◽

2019 ◽

Vol 19 (7) ◽

pp. 1646 ◽

Cited By ~ 5

Author(s):

Justyna Szerement ◽

Aleksandra Woszczyk ◽

Agnieszka Szypłowska ◽

Marcin Kafarski ◽

Arkadiusz Lewandowski ◽

...

Keyword(s):

Dielectric Permittivity ◽

Water Content ◽

Sandy Loam ◽

Sample Volume ◽

Time Domain Reflectometry ◽

Complex Dielectric Permittivity ◽

The Real ◽

Electromagnetic Simulations ◽

Different Diameters ◽

Permittivity Spectrum

This paper presents a novel seven-rod sensor used for time-domain reflectometry (TDR) and frequency-domain reflectometry (FDR) measurements of soil water content in a well-defined sample volume. The probe directly measures the complex dielectric permittivity spectrum and for this purpose requires three calibration media: air, water, and ethanol. Firstly, electromagnetic simulations were used to study the influence of the diameter of a container on the sensitivity zone of the probe with respect to the measured calibration media and isopropanol as a verification liquid. Next, the probe was tested in three soils—sandy loam and two silt loams—with six water contents from air-dry to saturation. The conversion from S 11 parameters to complex dielectric permittivity from vector network analyzer (VNA) measurements was obtained using an open-ended liquid procedure. The simulation and measurement results for the real part of the isopropanol dielectric permittivity obtained from four containers with different diameters were in good agreement with literature data up to 200 MHz. The real part of the dielectric permittivity was extracted and related to the moisture of the tested soil samples. Relations between the volumetric water content and the real part of the dielectric permittivity (by FDR) and apparent dielectric permittivity (by TDR) were compared with Topp’s equation. It was concluded that the best fit to Topp’s equation was observed in the case of a sandy loam. Data calculated according to the equation proposed by Malicki, Plagge, and Roth gave results closer to Topp’s calibration. The obtained results indicated that the seven-rod probe can be used to accurately measure of the dielectric permittivity spectrum in a well-defined sample volume of about 8 cm3 in the frequency range from 20 MHz to 200 MHz.

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Rapid Determination of Sufentanil in Human Plasma by UHPLC–QqQ-MS-MS

Journal of Analytical Toxicology ◽

10.1093/jat/bkaa123 ◽

2020 ◽

Author(s):

Marcin Zawadzki ◽

Grzegorz Kowalski ◽

Agnieszka Chłopaś-Konowałek ◽

Marta Siczek ◽

Małgorzata Sobieszczańska ◽

...

Keyword(s):

Human Plasma ◽

Lower Limit ◽

Rapid Determination ◽

Ultra Performance Liquid Chromatography ◽

Sample Volume ◽

Small Sample ◽

Plasma Samples ◽

Limit Of Quantification ◽

Detection And Identification

Abstract This paper presents a rapid, sensitive and precise method developed and validated for the quantification of sufentanil in biological samples using ultra-performance liquid chromatography coupled with QqQ-MS-MS. Plasma samples were extracted with simple and fast liquid-liquid extraction (ethyl acetate, pH 9). Calibration curve showed linearity in the concentration range of 0.005–30 µg/L. The lower limit of quantification was 0.010 µg/L. The most important method features are low lower limit of quantification value, simple plasma extraction and small sample volume. This method is suitable not only for evaluation of the pharmacokinetics, toxicology, bioavailability and clinical pharmacology of sufentanil but also for the detection and identification of this compound in human plasma samples for forensic purposes.

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Aptamer-Based Detection of Ampicillin in Urine Samples

Antibiotics ◽

10.3390/antibiotics9100655 ◽

2020 ◽

Vol 9 (10) ◽

pp. 655

Author(s):

Matthew D. Simmons ◽

Lisa M. Miller ◽

Malin O. Sundström ◽

Steven Johnson

Keyword(s):

Health Care ◽

General Population ◽

Bacterial Resistance ◽

Sample Volume ◽

Small Sample ◽

Urine Samples ◽

Drug Resistant ◽

Relevant Range ◽

Small Sample Volume

The misuse of antibiotics in health care has led to increasing levels of drug resistant infections (DRI’s) occurring in the general population. Most technologies developed for the detection of DRI’s typically focus on phenotyping or genotyping bacterial resistance rather than on the underlying cause and spread of DRI’s; namely the misuse of antibiotics. An aptameric based assay has been developed for the monitoring of ampicillin in urine samples, for use in determining optimal antibiotic dosage and monitoring patient compliance with treatment. The fluorescently labelled aptamers were shown to perform optimally at pH 7, ideal for buffered clinical urine samples, with limits of detection as low as 20.6 nM, allowing for determination of ampicillin in urine in the clinically relevant range of concentrations (100 nM to 100 µM). As the assay requires incubation for only 1 h with a small sample volume, 50 to 150 µL, the test would fit within current healthcare pathways, simplifying the adoption of the technology.

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New System for Automated Extraction and Simultaneous Determination of Serum Cholesterol and Triglycerides

Clinical Chemistry ◽

10.1093/clinchem/21.10.1430 ◽

1975 ◽

Vol 21 (10) ◽

pp. 1430-1436 ◽

Cited By ~ 6

Author(s):

Dorothy F Wease ◽

Eli S Espinosa ◽

Yvonne J Anderson

Keyword(s):

Simultaneous Determination ◽

Lipid Extraction ◽

Small Animal ◽

Correlation Coefficients ◽

Sample Volume ◽

Small Sample ◽

Automated System ◽

Coefficients Of Variation ◽

Precision Time

Abstract We describe an automated system for serum lipid extraction and simultaneous determination of cholesterol and triglycerides, with use of continuous-flow equipment. A sample volume of 100 µl of serum is required, and samples are processed at the rate of 20 per hour, which may be increased with slight loss in precision. Time from sample pickup to recorder readout is about 25 min. The system makes use of established colorimetric reactions, and the values obtained agree with ranges currently reported in the literature. Correlation coefficients for results of the automated and manual methods were 0.98 for cholesterol and 0.99 for triglycerides, and the day-to-day coefficients of variation were 1.8% for cholesterol (1 SD = 34 mg/liter) and 3.4% for triglycerides (1 SD = 37 mg/liter). The small sample volume, precision, accuracy, speed, and comparative economy of reagents make this system particularly suitable for multiphasic screening, pediatrics, and small-animal research.

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Paper-based microfluidic devices based on 3D network polymer hydrogel for the determination of glucose in human whole blood

RSC Advances ◽

10.1039/c9ra04278d ◽

2019 ◽

Vol 9 (56) ◽

pp. 32367-32374 ◽

Cited By ~ 3

Author(s):

Rong-Yu He ◽

Hsin-Yi Tseng ◽

Hsia-An Lee ◽

Yu-Ci Liu ◽

Igor O. Koshevoy ◽

...

Keyword(s):

Whole Blood ◽

Microfluidic Devices ◽

Sample Volume ◽

Small Sample ◽

Glucose Detection ◽

Network Polymer ◽

Blood Samples ◽

Human Whole Blood ◽

3D Network

In this study, optical microfluidic paper analytical devices (μPADs) for glucose detection from whole blood samples with a small sample volume (2 μL) have been developed on a single paper.

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Direct determination of plasma copper and zinc in infants by atomic absorption with discrete nebulization.

Clinical Chemistry ◽

10.1093/clinchem/27.8.1445 ◽

1981 ◽

Vol 27 (8) ◽

pp. 1445-1447 ◽

Cited By ~ 35

Author(s):

T Makino ◽

K Takahara

Keyword(s):

Atomic Absorption ◽

Direct Determination ◽

Absorption Spectrometry ◽

Sample Volume ◽

Reference Intervals ◽

Small Sample ◽

Time Saving ◽

Copper And Zinc ◽

Plasma Copper

Abstract A new micromethod for the determination of copper and zinc is presented. Sample volumes can be as little as 10 (Cu) and 20 (Zn) microliter of plasma or serum, by using discrete (small sample volume) nebulization in place of conventional nebulization in place of conventional nebulization in atomic absorption spectrometry. The present method has slightly poorer precision than the conventional nebulization method, but has the advantages of requiring commercially available apparatus without any modification, involving simple sample preparation, and being time-saving. Results agree well with those by the trichloroacetic acid deproteinization method. In addition, this method is useful for pediatric samples, and we report reference intervals for full-term and premature infants, as well as adults.

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Rapid, Accurate Technique for Determination of Carbon Monoxide in Blood

Clinical Chemistry ◽

10.1093/clinchem/20.5.533 ◽

1974 ◽

Vol 20 (5) ◽

pp. 533-537 ◽

Cited By ~ 34

Author(s):

Thomas E Dahms ◽

Steven M Horvath

Keyword(s):

Carbon Monoxide ◽

Vortex Method ◽

Sample Volume ◽

Rapid Analysis ◽

Small Sample ◽

Chromatographic Technique ◽

Gas Extraction ◽

Solubility Coefficient ◽

Human Blood Samples

Abstract We report a chromatographic technique in which a vortex method of gas extraction and a thermal conductivity detector are used to measure carbon monoxide in blood. This method has the advantages of a small sample volume (100 µl), a rapid analysis time (3 min), ease of operation, and a high correlation with results of the standard gasometric method over the entire possible range (r = 0.999). The accuracy of this method (coefficient of variation) for measuring CO in human blood samples was 1.7%. With it, dissolved CO can be accurately measured, as demonstrated by the Bunsen solubility coefficient for plasma CO by this method of 22.0 ml of CO per liter of water per atm. (101 kN/m2) at 24 °C (theoretical value: 21.8).

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Evaporation through a soil mulch in relation to mulch characteristics and evaporativity

Soil Research ◽

10.1071/sr9930131 ◽

1993 ◽

Vol 31 (2) ◽

pp. 131 ◽

Cited By ~ 13

Author(s):

SK Jalota

Keyword(s):

Wind Speed ◽

Flux Density ◽

Strong Interaction ◽

Sandy Loam ◽

Silt Loam ◽

Atmospheric Parameters ◽

Treated Soil ◽

Vapour Flux ◽

Dry Soil

A simple equation describing the effects of atmospheric parameters and soil mulch characteristics upon vapour flux density through a dry soil mulch was successfully developed. Determination of vapour flux density was made from columns of diameter 0.1 m and length 0.95 m. These were filled with silt loam and sandy loam soils with surfactant-treated soil mulch on the surface which varied in thickness and porosity. The experiments were conducted under different atmospheric evaporativities (E0), which comprised a number of combinations of wind speed and ambient temperature. The observed vapour flux density and that computed with Hanks' equation matched well. The results indicated that evaporation under a given E0 was affected more by temperature than wind speed. However, vapour flux density showed a strong interaction with wind speed, temperature and the soil mulch characteristics such as porosity and thickness.

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A High-Performance Liquid Chromatographic Assay for the Determination of Itraconazole Concentration Using Solid-Phase Extraction and Small Sample Volume

Therapeutic Drug Monitoring ◽

10.1097/00007691-199510000-00014 ◽

1995 ◽

Vol 17 (5) ◽

pp. 522-525 ◽

Cited By ~ 14

Author(s):

Nader Rifai ◽

Masayuki Sakamoto ◽

Orah Platt ◽

Carlo Brugnara

Keyword(s):

Solid Phase Extraction ◽

High Performance ◽

Solid Phase ◽

High Performance Liquid Chromatographic ◽

Sample Volume ◽

Small Sample ◽

Phase Extraction ◽

Liquid Chromatographic ◽

Small Sample Volume

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A modified dielectric probe for increased measurement volume of soil water content

10.5194/egusphere-egu2020-17909 ◽

2020 ◽

Author(s):

Aleksandra Woszczyk ◽

Justyna Szerement ◽

Arkadiusz Lewandowski ◽

Marcin Kafarski ◽

Agnieszka Szypłowska ◽

...

Keyword(s):

Dielectric Permittivity ◽

Water Content ◽

Electromagnetic Waves ◽

Mechanical Damage ◽

Direct Methods ◽

Soil Disturbance ◽

Sample Volume ◽

Time Domain Reflectometry ◽

Frequency Range ◽

Probe Calibration

The information of water amount in soil is essential in many fields (e.g. agriculture, forestry, hydrology). Methods to determine water content (WC) can be classified as direct and indirect. Direct methods are connected with the destruction of a sample, are time-consuming and impractical for the measurements in the crop fields. Indirect methods ensure non-destructive and in situ measurements and depend on monitoring a dielectric soil property which is a function of WC. The soil dielectric permittivity is one of the used properties which may be determined by time domain reflectometry (TDR) or frequency domain reflectometry (FDR) techniques. TDR probes are expensive and can be easily damaged at multiple insertions to soil. The open-ended (OE) probes, well-known for their application in the measurements of the complex dielectric permittivity of materials in broadband frequency range, are more resistant to mechanical damage but they are characterized by low penetration depth of electromagnetic waves. Therefore, there is a need to develop sensors able to measure bigger volumes and at the same time sufficiently durable for multiple insertions in soil. &#160;&#160;&#160;&#160;The objective of this work was to test the performance of an open-ended dielectric probe with an antenna (OE-A) in the frequency range 1 MHz &#8211; 6 GHz for two mineral soils using vector network analyzer (VNA) one port (reflective) measurements. Firstly, numerical simulations of the probe using Ansys HFSS software were performed. Secondly, the probe calibration was done on the reference materials (air, distilled water and ethanol). Thirdly, the soils measurements were done to check the possibility to determine soil moisture. &#160;&#160;The obtained results show that the tested probe can be applied for fast moisture measurement with minimal soil disturbance. The real part of dielectric permittivity (&#949;&#8217;) obtained for the tested soils was connected with their moisture and the relation between &#949;&#8217; and volumetric water content was determined. Additionally, the effect of the sample volume was considered and the relation between the high-frequency limit and diameter of the sample was determined. &#160;&#160;&#160;&#160;Acknowledgement:This research was supported by the National Centre for Research and Development (BIOSTRATEG/343547/8/NCBR/2017).

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