Combined Gel Probes for the In Situ Determination of Dissolved Reactive Phosphorus in Porewaters and Characterization of Sediment Reactivity

2008 ◽  
Vol 42 (14) ◽  
pp. 5112-5117 ◽  
Author(s):  
Phil Monbet ◽  
Ian D. McKelvie ◽  
Paul. J. Worsfold
Keyword(s):  
Dissolved Reactive Phosphorus ◽  
Reactive Phosphorus

Modified ferron assay for speciation characterization of hydrolyzed Al(III): a precise k value based judgment

2009 ◽  
Vol 59 (4) ◽  
pp. 823-832 ◽  
Author(s):  
Ye Changqing ◽  
Wang Dongsheng ◽  
Wu Xiaohong ◽  
Qu Jiuhui ◽  
John Gregory
Keyword(s):  
Kinetic Constant ◽  
Nonlinear Least Squares ◽  
Precise Determination ◽  
K Value ◽  
First Order ◽  
First Order Kinetics ◽  
Parallel Reactions

The speciation of Al-OH complexes in terms of Ala, Alb and Alc could be achieved by traditional ferron assay and Alb is generally considered as Al13, however, the inherent correlation between them remains an enigma. This paper presents a modified ferron assay to get precise determination of Al13 using nonlinear least squares analysis, and to clarify the correlation between Alb and Al13. Two parallel reactions conforming to pseudo-first-order kinetics can simulate the complicate reactions between polynuclear complexes and ferron successfully. Four types of experimental kinetic constant (k value) of Al-OH complexes can be observed by this method when investigating three typical aluminium solutions. Comparing with the results of 27Al NMR, the species with moderate kinetics around 0.001 s−1 can be confirmed to resemble to Al13 polycation. The other types of kinetics are also well-regulated in partially neutralized aluminium solutions with various OH/Al ratios (b values) in the range 0 ∼ 2.5. It would provide potential means to trace the in-situ formation of Al13 in dilute solutions such as coagulation with Al-based coagulants

In situ structure and force characterization of 2D nano-colloids at the air/water interface

Soft Matter ◽  
2019 ◽  
Vol 15 (42) ◽  
pp. 8475-8482
Author(s):  
Giovanni Li-Destri ◽  
Roberta Ruffino ◽  
Nunzio Tuccitto ◽  
Giovanni Marletta
Keyword(s):  
Quantitative Determination ◽  
Experimental Method ◽  
Water Interface ◽  
Liquid Interfaces ◽  
Interaction Forces ◽  
Air Water Interface

We have developed a novel experimental method, which enables quantitative determination of interaction forces between interfacial nanoparticles as a function of the inter-particle distance at liquid interfaces.

In situ calibration and [H+] sensitivity of the fluorescent Na+indicator SBFI

2001 ◽  
Vol 280 (6) ◽  
pp. C1623-C1633 ◽  
Author(s):  
Abdoullah Diarra ◽  
Claire Sheldon ◽  
John Church
Keyword(s):  
Ph Dependence ◽  
Apparent Dissociation Constant ◽  
Simple Method ◽  
Standard Equation ◽  
In Situ Calibration ◽  
Apparent Decrease ◽  
Calibration Techniques

Despite the popularity of Na+-binding benzofuran isophthalate (SBFI) to measure intracellular free Na+ concentrations ([Na+]i), the in situ calibration techniques described to date do not favor the straightforward determination of all of the constants required by the standard equation (Grynkiewicz G, Poenie M, and Tsien RY. J Biol Chem 260: 3440–3450, 1985) to convert the ratiometric signal into [Na+]. We describe a simple method in which SBFI ratio values obtained during a “full” in situ calibration are fit by a three-parameter hyperbolic equation; the apparent dissociation constant ( K d) of SBFI for Na+ can then be resolved by means of a three-parameter hyperbolic decay equation. We also developed and tested a “one-point” technique for calibrating SBFI ratios in which the ratio value obtained in a neuron at the end of an experiment during exposure to gramicidin D and 10 mM Na+is used as a normalization factor for ratios obtained during the experiment; each normalized ratio is converted to [Na+]i using a modification of the standard equation and parameters obtained from a full calibration. Finally, we extended the characterization of the pH dependence of SBFI in situ. Although the K d of SBFI for Na+ was relatively insensitive to changes in pH in the range 6.8–7.8, acidification resulted in an apparent decrease, and alkalinization in an apparent increase, in [Na+]i values. The magnitudes of the apparent changes in [Na+]ivaried with absolute [Na+]i, and a method was developed for correcting [Na+]i values measured with SBFI for changes in intracellular pH.

Continuous Flow Analysis Method for Determination of Dissolved Reactive Phosphorus in Ice Cores

2013 ◽  
Vol 47 (21) ◽  
pp. 12325-12332 ◽  
Author(s):  
Helle Astrid Kjær ◽  
Paul Vallelonga ◽  
Anders Svensson ◽  
Magnus Elleskov L. Kristensen ◽  
Catalin Tibuleac ◽  
...  
Keyword(s):  
Continuous Flow ◽  
Flow Analysis ◽  
Ice Cores ◽  
Analysis Method ◽  
Continuous Flow Analysis ◽  
Dissolved Reactive Phosphorus ◽  
Reactive Phosphorus

scholarly journals Advancements in Techniques for Calibration and Characterization of In Situ Optical Particle Measuring Probes, and Applications to the FSSP-100 Probe

2007 ◽  
Vol 24 (5) ◽  
pp. 745-760 ◽  
Author(s):  
Dagmar Nagel ◽  
Uwe Maixner ◽  
Walter Strapp ◽  
Mohammed Wasey
Keyword(s):  
High Speed ◽  
Sample Volume ◽  
Absolute Calibration ◽  
Droplet Generator ◽  
Measuring Systems ◽  
Distortion Matrix ◽  
Measured Particle

Abstract Advancements in techniques for the operational calibration and characterization of instrument performance of the Particle Measuring Systems, Inc. (PMS), forward scattering spectrometer probe (FSSP) and optical array probes (OAPs) are presented, which also can be used for most in situ particle-measuring optical probes on the market. These techniques include the determination of a distortion matrix to correct for instrumental broadening of the measured particle size distribution. A new version of a monodisperse droplet generator is introduced for absolute calibration in the size range between 10 and 100 μm. In addition, a high-speed technique was employed for the determination of airspeed influence on the sample volume and the sizing of particles. The calibration of a PMS FSSP with real water droplets may be significantly different from the usual calibration with glass beads. High-speed measurements simulate particles at speeds of up to about 250 m s−1. Particle undersizing and the decrease of the sample volume with increasing airspeed are described. The use of the modular tools, built for this work, is discussed for probe alignment, functionality checks, and general characterization and diagnostics both in laboratory and field environments.

scholarly journals Characterization of a rapid cellular-fractionation technique for hepatocytes. Application in the measurement of mitochondrial membrane potential in situ

1984 ◽  
Vol 219 (2) ◽  
pp. 375-382 ◽  
Author(s):  
S B Shears ◽  
C J Kirk
Keyword(s):  
Incubation Medium ◽  
Plasma Membranes ◽  
Electrical Potential ◽  
Cell Fractionation ◽  
Marker Enzyme ◽  
Cell Nuclei ◽  
Electrical Potentials

A rapid cellular-fractionation technique [Hoek, Nicholls & Williamson (1980) J. Biol. Chem. 255, 1458-1464] was further characterized by using hepatocytes. Of the mitochondrial marker-enzyme activity, 80% was routinely separated from 71-98% of the total cell activities of marker enzymes for plasma membranes, Golgi-membranes, endoplasmic reticulum, lysosomes and cytosol. The mitochondria were contaminated with 53% of cell nuclei. [3H]Triphenylmethylphosphonium ion (TPMP+) was added to hepatocytes in an attempt to measure cellular transmembrane electrical potentials. After rapid cell fractionation the electrical potential between mitochondria in situ and the incubation medium was found to be 202 mV. This value was slightly increased when hepatocytes were treated with oligomycin, but substantially decreased by oligomycin plus an uncoupler of oxidative phosphorylation. Although estimates of TPMP+ binding were obtained, substantial difficulties prevented the accurate measurement of the electrical potential across the plasma membrane. It is concluded that TPMP+ may be employed to demonstrate the integrity of mitochondria during the fractionation procedures. However, the cation is inadequate for the determination of the separate components of the electrical potential between the mitochondrial matrix and the incubation medium.

In situ determination of kinetic parameters for biofilms: Isolation and characterization of oligotrophic biofilms

1986 ◽  
Vol 28 (11) ◽  
pp. 1753-1760 ◽  
Author(s):  
Bruce E. Rittmann ◽  
LouAnn Crawford ◽  
Cynthia K. Tuck ◽  
Eun Namkung
Keyword(s):  
Kinetic Parameters ◽  
Isolation And Characterization
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