scholarly journals Characterization of the Natural Colloidal TiO2 Background in Soil

Separations ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 50 ◽  
Author(s):  
Allan Philippe ◽  
Daniel Campos ◽  
Jean-Michel Guigner ◽  
Christian Buchmann ◽  
Dörte Diehl ◽  
...  
Keyword(s):  
Size Distribution ◽  
Method Development ◽  
Fluorescence Analysis ◽  
Engineered Nanoparticles ◽  
Detection Methods ◽  
Icp Oes ◽  
Hydrodynamic Chromatography ◽  
Precise Knowledge ◽  
Distribution Mode ◽  
Colloidal Fraction

An increasing amount of TiO2 engineered nanoparticles (TNP) is released into soils and sediments, increasing the need for dedicated detection methods. Titanium is naturally present in soils at concentrations typically much higher than the estimated concentrations for TNP. Therefore, a precise knowledge of this natural background, including the colloidal fraction, is required for developing adapted strategies for detecting TNP. In this study, we characterized the natural colloidal Ti-background by analyzing eight soils with different properties and origins. A combination of X-ray fluorescence analysis and ICP-OES was used for determining the silicate bound fraction, which was a minor fraction for all soils (0–32%). The colloidal fraction obtained by extracting colloids from soil prior to ICP-OES measurements ranged between 0.3% and 7%. Electron microscopy and hydrodynamic chromatography confirmed that Ti in the form of colloids or larger particles was mostly present as TiO2 minerals with a fraction smaller than 100 nm. The size distribution mode of the extracted colloids determined using hydrodynamic chromatography ranged between 80 and 120 nm. The chromatograms suggested a broad size distribution with a significant portion below 100 nm. In addition to these data, we also discuss possible implications of our findings for the method development for detecting TNP in soils.

scholarly journals Current Trends and Challenges for Rapid SMART Diagnostics at Point-of-Site Testing for Marine Toxins

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2499
Author(s):  
Michael Dillon ◽  
Maja A. Zaczek-Moczydlowska ◽  
Christine Edwards ◽  
Andrew D. Turner ◽  
Peter I. Miller ◽  
...  
Keyword(s):  
Method Development ◽  
Regulatory Control ◽  
Detection Methods ◽  
Control Individual ◽  
Mouse Bioassay ◽  
Future Market ◽  
Site Testing ◽  
Wide Range ◽  
Development And Validation ◽  
Analytical Standards

In the past twenty years marine biotoxin analysis in routine regulatory monitoring has advanced significantly in Europe (EU) and other regions from the use of the mouse bioassay (MBA) towards the high-end analytical techniques such as high-performance liquid chromatography (HPLC) with tandem mass spectrometry (MS). Previously, acceptance of these advanced methods, in progressing away from the MBA, was hindered by a lack of commercial certified analytical standards for method development and validation. This has now been addressed whereby the availability of a wide range of analytical standards from several companies in the EU, North America and Asia has enhanced the development and validation of methods to the required regulatory standards. However, the cost of the high-end analytical equipment, lengthy procedures and the need for qualified personnel to perform analysis can still be a challenge for routine monitoring laboratories. In developing regions, aquaculture production is increasing and alternative inexpensive Sensitive, Measurable, Accurate and Real-Time (SMART) rapid point-of-site testing (POST) methods suitable for novice end users that can be validated and internationally accepted remain an objective for both regulators and the industry. The range of commercial testing kits on the market for marine toxin analysis remains limited and even more so those meeting the requirements for use in regulatory control. Individual assays include enzyme-linked immunosorbent assays (ELISA) and lateral flow membrane-based immunoassays (LFIA) for EU-regulated toxins, such as okadaic acid (OA) and dinophysistoxins (DTXs), saxitoxin (STX) and its analogues and domoic acid (DA) in the form of three separate tests offering varying costs and benefits for the industry. It can be observed from the literature that not only are developments and improvements ongoing for these assays, but there are also novel assays being developed using upcoming state-of-the-art biosensor technology. This review focuses on both currently available methods and recent advances in innovative methods for marine biotoxin testing and the end-user practicalities that need to be observed. Furthermore, it highlights trends that are influencing assay developments such as multiplexing capabilities and rapid POST, indicating potential detection methods that will shape the future market.

scholarly journals Comparison of Serum, Plasma, and Liver Zinc Measurements by AAS, ICP-OES, and ICP-MS in Diverse Laboratory Settings

2021 ◽  
Author(s):  
Andrew G. Hall ◽  
Janet C. King ◽  
Christine M. McDonald
Keyword(s):  
Inductively Coupled Plasma ◽  
Method Development ◽  
Geometric Mean ◽  
Zinc Content ◽  
Plasma Zinc ◽  
Icp Oes ◽  
Percent Error ◽  
Accuracy And Precision ◽  
Icp Ms ◽  
Standardized Method

AbstractProgress improving zinc nutrition globally is slowed by limited understanding of population zinc status. This challenge is compounded when small differences in measurement can bias the determination of zinc deficiency rates. Our objective was to evaluate zinc analytical accuracy and precision among different instrument types and sample matrices using a standardized method. Participating laboratories analyzed zinc content of plasma, serum, liver samples, and controls, using a standardized method based on current practice. Instrument calibration and drift were evaluated using a zinc standard. Accuracy was evaluated by percent error vs. reference, and precision by coefficient of variation (CV). Seven laboratories in 4 countries running 9 instruments completed the exercise: 4 atomic absorbance spectrometers (AAS), 1 inductively coupled plasma optical emission spectrometer (ICP-OES), and 4 ICP mass spectrometers (ICP-MS). Calibration differed between individual instruments up to 18.9% (p < 0.001). Geometric mean (95% CI) percent error was 3.5% (2.3%, 5.2%) and CV was 2.1% (1.7%, 2.5%) overall. There were no significant differences in percent error or CV among instrument types (p = 0.91, p = 0.15, respectively). Among sample matrices, serum and plasma zinc measures had the highest CV: 4.8% (3.0%, 7.7%) and 3.9% (2.9%, 5.4%), respectively (p < 0.05). When using standardized materials and methods, similar zinc concentration values, accuracy, and precision were achieved using AAS, ICP-OES, or ICP-MS. However, method development is needed for improvement in serum and plasma zinc measurement precision. Differences in calibration among instruments demonstrate a need for harmonization among laboratories.

Size distribution measurement of microplastics using a temporally and spatially resolved inductively coupled plasma optical emission spectrometer (ICP-OES)

2021 ◽  
Author(s):  
Yoshiyuki Teramoto ◽  
Hyun-Ha Kim
Keyword(s):  
Size Distribution ◽  
Inductively Coupled Plasma ◽  
Optical Emission ◽  
Icp Oes ◽  
Distribution Measurement ◽  
Inductively Coupled ◽  
Spatially Resolved ◽  
Optical Emission Spectrometer

We studied microplastics in water using a temporally and spatially resolved ICP-OES with an inverted-type torch.

scholarly journals Current PCR Methods for the Detection, Identification and Quantification of Genetically Modified Organisms(GMOs): a Brief Review

2000 ◽  
Vol 19 (2) ◽  
pp. 85-96 ◽  
Author(s):  
F Gadani ◽  
G Bindler ◽  
H Pijenburg ◽  
L Rossi ◽  
J Zuber
Keyword(s):  
Dna Sequences ◽  
Method Development ◽  
Genetically Modified Organisms ◽  
Genetically Modified ◽  
Value Added ◽  
Detection Methods ◽  
Agricultural Crops ◽  
The European Union ◽  
Gmo Detection ◽  
Food Ingredients

AbstractAnalytical methods based on the polymerase chain reaction (PCR) technology are increasingly used for the detection of deoxyribonucleic acid (DNA) sequences associated with genetically modified organisms (GMOs). In the European Union and Switzerland, mandatory labeling of novel foods and food ingredients consisting of, or containing GMOs is required according to food regulations and is triggered by the presence of newly introduced foreign DNA sequences, or newly expressed proteins. In order to meet regulatory and consumer demand, numerous PCR-based methods have been developed which can detect, identify and quantify GMOs in agricultural crops, food and feed. Moreover, the determination of genetic identity allows for segregation and traceability (identity preservation) throughout the supply chain of GM crops that have been enhanced with value-added quality traits. Prerequisites for GMO detection include a minimum amount of the target gene and prior knowledge of the type of genetic modification, such as virus or insect resistance traits, including controlling elements (promoters and terminators). Moreover, DNA extraction and purification is a critical step for the preparation of PCR-quality samples, particularly for processed agricultural crops such as tobacco. This paper reviews the state-of-the-art of PCR-based method development for the qualitative and quantitative determination and identification of GMOs, and includes a short summary of official and validated GMO detection methods.

Recent advances in inductively coupled plasma optical emission spectrometry

2017 ◽  
Vol 32 (7) ◽  
pp. 1283-1296 ◽  
Author(s):  
George L. Donati ◽  
Renata S. Amais ◽  
Charles B. Williams
Keyword(s):  
Inductively Coupled Plasma ◽  
Method Development ◽  
Trace Element Analysis ◽  
Optical Emission ◽  
Emission Spectrometry ◽  
Icp Oes ◽  
Element Analysis ◽  
Inductively Coupled ◽  
Recent Developments ◽  
Plasma Optical Emission Spectrometry

Review of recent developments in instrumentation, calibration strategies, and method development and applications of ICP OES for trace element analysis.

scholarly journals Lake spray aerosol generation: a method for producing representative particles from freshwater wave breaking

2016 ◽  
Vol 9 (9) ◽  
pp. 4311-4325 ◽  
Author(s):  
Nathaniel W. May ◽  
Jessica L. Axson ◽  
Alexa Watson ◽  
Kerri A. Pratt ◽  
Andrew P. Ault
Keyword(s):  
Size Distribution ◽  
Atmospheric Aerosols ◽  
Wave Breaking ◽  
Lake Michigan ◽  
Cloud Condensation Nuclei ◽  
Size Distributions ◽  
Salt Solutions ◽  
Synthetic Seawater ◽  
Number Size Distribution ◽  
Distribution Mode

Abstract. Wave-breaking action in bodies of freshwater produces atmospheric aerosols via a similar mechanism to sea spray aerosol (SSA) from seawater. The term lake spray aerosol (LSA) is proposed to describe particles formed by this mechanism, which have been observed over the Laurentian Great Lakes. Though LSA has been identified from size distribution measurements during a single measurement campaign, no measurements of LSA composition or relationship to bubble-bursting dynamics have been conducted. An LSA generator utilizing a plunging jet, similar to many SSA generators, was constructed for the generation of aerosol from freshwater samples and model salt solutions. To evaluate this new generator, bubble and aerosol number size distributions were measured for salt solutions representative of freshwater (CaCO3) and seawater (NaCl) at concentrations ranging from that of freshwater to seawater (0.05–35 g kg−1), synthetic seawater (inorganic), synthetic freshwater (inorganic), and a freshwater sample from Lake Michigan. Following validation of the bubble and aerosol size distributions using synthetic seawater, a range of salt concentrations were investigated. The systematic studies of the model salts, synthetic freshwater, and Lake Michigan sample indicate that LSA is characterized by a larger number size distribution mode diameter of 300 nm (lognormal), compared to seawater at 110 nm. Decreasing salt concentrations from seawater to freshwater led to greater bubble coalescence and formation of larger bubbles, which generated larger particles and lower aerosol number concentrations. This resulted in a bimodal number size distribution with a primary mode (180 ± 20 nm) larger than that of SSA, as well as a secondary mode (46 ± 6 nm) smaller than that of SSA. This new method for studying LSA under isolated conditions is needed as models, at present, utilize SSA parameterizations for freshwater systems, which do not accurately predict the different size distributions observed for LSA or resulting climate properties. Given the abundance of freshwater globally, this potentially important source of aerosol needs to be thoroughly characterized, as the sizes produced are relevant to light scattering, cloud condensation nuclei (CCN), and ice nuclei (IN) concentrations over bodies of freshwater.

Magnetoresistive Sensors and Magnetic Nanoparticles for Biotechnology

2004 ◽  
Vol 853 ◽  
Author(s):  
Guenter Reiss ◽  
Hubert Brueckl ◽  
Andreas Huetten ◽  
Joerg Schotter ◽  
Monika Brzeska ◽  
...  
Keyword(s):  
Size Distribution ◽  
Giant Magnetoresistance ◽  
Magnetic Particles ◽  
Magnetic Moments ◽  
Fluorescent Detection ◽  
Detection Methods ◽  
Colloidal Synthesis ◽  
Stray Field ◽  
Magnetic Carriers ◽  
Magnetic Markers

ABSTRACTMagnetoresistive Biosensors use a new detection method for molecular recognition reactions based on two recently developed techniques and devices: Magnetic markers and XMR –sensors, where XMR means either GiantMagneto- (GMR) or Tunneling-MagnetoResistance (TMR). The markers are specifically attached to the target molecules, and their magnetic stray field is picked up by the embedded magnetoresistive sensor as a change of the electrical resistance. Compared to established, e.g. fluorescent, detection methods, magnetic biosensors have a number of advantages, including low molecular detection limits, flexibility and the direct availability of an electronic signal suitable for further automated analysis. This makes them a promising choice for the detection units of future widespread and easy to use lab-on-a-chip systems or biochips.Both the measurement technique using XMR-sensors as well as new developments in the preparation of magnetic carriers are discussed here. Different configurations are discussed and the results for Giant Magnetoresistance sensors are compared to an analysis of the same biological systems marked with fluorescence dyes. Down to a concentration of about 10 pg/μl of, e.g., DNA molecules, the magnetoresistive technique is competitive with nowadays standard analysis methods. The capability of the TMR sensors to detect even single markers is additionally demonstrated by a model experiment using the tip of a magnetic force microscope to meamic the presence of a magnetic particle on top of the sensor surface.The magnetic carriers (beads) usually detected by the sensors consist of paramagnetic magnetite particles embedded in a polymer matrix with sizes from some μm down to about 100nm. They are linked to, e.g., DNA or proteins (often by a avidin-biotin bond) and thereby enable highly specific detection of complementary molecules. These magnetic particles often suffer from their broad size distribution and the relatively small magnetic moment. With the new colloidal synthesis of superpara- or ferromagnetic Co, CoFe and FePt nanocrystals by, e.g., pyrolythic decomposition of CVD precursor molecules, magnetic markers with superior magnetic moments, smaller size and size distribution can be produced. Here, the question about their potential to replace magnetite is addressed. Starting from a magnetic analysis of the corresponding magnetophoretic mobility of Co and FeCo based alloys their synthesis and resulting microstructural and magnetic properties as function of the underlying particle size distribution and the stability of the oleic acid ligand are discussed.Moreover, the magnetic particles offer an additional feature: They can be manipulated on chip via currents running through specially designed line patterns. We show, that this manipulation can be performed in a precise and reproducible manner, enabling locally enhanced concentration or even the measurement of binding forces with very low loading rates.

scholarly journals Measurement of Vanadium Emissions from SCR Catalysts by ICP-OES: Method Development and First Results

2015 ◽  
Vol 1 (4) ◽  
pp. 292-297 ◽  
Author(s):  
T. J. Schildhauer ◽  
M. Elsener ◽  
J. Moser ◽  
I. Begsteiger ◽  
D. Chatterjee ◽  
...  
Keyword(s):  
Method Development ◽  
Icp Oes ◽  
Scr Catalysts ◽  
First Results
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