scholarly journals Determination of Surfactants in Environmental Samples. Part III. Non-Ionic Compounds

2013 ◽  
Vol 20 (3) ◽  
pp. 449-461 ◽  
Author(s):  
Ewa Olkowska ◽  
Marek Ruman ◽  
Anna Kowalska ◽  
Żaneta Polkowska
Keyword(s):  
Environmental Fate ◽  
Total Concentration ◽  
Ionic Surfactants ◽  
General View ◽  
Environmental Matrices ◽  
Solid Samples ◽  
Detection Techniques ◽  
Liquid Samples ◽  
Ionic Compounds

Abstract Non-ionic surface active agents are a diverse group of chemicals which have an uncharged polar head and a non-polar tail. They have different properties due to amphiphilic structure of their molecules. Commercial available non-ionic surfactants consist of the broadest spectrum of compounds in comparison with other types of such agents. Typically, non-ionic compounds found applications in households and industry during formulation of cleaning products, cosmetics, paints, preservative coatings, resins, textiles, pulp and paper, petroleum products or pesticides. Their are one of the most common use class of surfactants which can be potential pollution sources of the different compartment of environment (because of they widely application or discharging treated wastewaters to surface water and sludge in agricultural). It is important to investigate the behavior, environmental fate of non-ionic surfactants and their impact on living organisms (they are toxic and/or can disrupt endocrine functions). To solve such problems should be applied appropriated analytical tools. Sample preparation step is one of the most critical part of analytical procedures in determination of different compounds in environmental matrices. Traditional extraction techniques (LLE - for liquid samples; SLE - for solid samples) are time and solvent-consuming. Developments in this field result in improving isolation efficiency and decreasing solvent consumption (eg SPE and SPME - liquid samples or PLE, SFE and MAE - solid samples). At final determination step can be applied spectrophotometric technique, potentiometric titrametration or tensammetry (determination total concentration of non-ionic surfactants) or chromatographic techniques coupled with appropriated detection techniques (individual analytes). The literature data concerning the concentrations of non-ionic surfactants in the different compartments of the environment can give general view that various ecosystems are polluted by those compounds.

Determination of Bovine Lactoferrin in Food by HPLC with a Heparin Affinity Column for Sample Preparation

2017 ◽  
Vol 100 (1) ◽  
pp. 133-138 ◽  
Author(s):  
Yin Zhang ◽  
Fei Lou ◽  
Wei Wu ◽  
Xin Dong ◽  
Jia Ren ◽  
...  
Keyword(s):  
Low Cost ◽  
Great Promise ◽  
Array Detector ◽  
Affinity Column ◽  
Bovine Lactoferrin ◽  
Solid Samples ◽  
Detection Range ◽  
Liquid Samples ◽  
Heparin Affinity

Abstract An HPLC method was developed for the quantitative determination of bovine lactoferrin (bLF) in sterilized milk, modified milk, fermented milk, infant formula, adult formula, rice cereal, vitamin function drink, and protein powder products. bLF was first extracted with a phosphate buffer (pH 8), underwent cleanup in a heparin affinity column, and was detected by HPLC with a C4 column and diode-array detector at a wavelengthof 280 nm. The proposed method provided a linear detection range of 10.0–1000 μg/mL with an LOD of 0.6 mg/100 g in liquid samples and 3 mg/100 g in solid samples and an LOQ of 2 mg/100 g in liquid samples and 10 mg/100 g in solid samples. In addition, the method showed good recovery for various samples, ranging from 76 to 96%. The method had several remarkable advantages, including ease of handling, high sensitivity and accuracy, good reproducibility, and low-cost detection. Based on the distinctive properties presented here, webelieve the proposed HPLC assay holds great promise for the oversight and detection of bLF in testing organizations, dairy enterprises, and regulatory authorities.

Partitioning and stability of engineered ZnO nanoparticles in soil suspensions using flow field-flow fractionation

2007 ◽  
Vol 4 (1) ◽  
pp. 8 ◽  
Author(s):  
Laura J. Gimbert ◽  
Rebecca E. Hamon ◽  
Phil S. Casey ◽  
Paul J. Worsfold
Keyword(s):  
Particle Size ◽  
Flow Field ◽  
Zno Nanoparticles ◽  
Environmental Fate ◽  
Engineered Nanoparticles ◽  
Field Flow Fractionation ◽  
Pore Waters ◽  
Environmental Matrices ◽  
Flow Fractionation

Environmental context. Nanoparticulate materials are increasingly being used as catalysts and lubricants, for pollution control and drug delivery, and in electronics, fabrics, cosmetics and sunscreens. In spite of this growth, information about the fate and toxicity of nanoparticles in the environment is limited, partly due to the lack of techniques capable of measuring nanoparticles in complex environmental matrices. One emerging tool, flow field-flow fractionation, can be used to determine the presence and particle size distribution of engineered nanoparticles, for example in soil pore waters, thereby enhancing our understanding of their environmental fate and impacts. Abstract. This paper reports preliminary results for the determination of engineered ZnO nanoparticles using flow field-flow fractionation (FlFFF). This separation technique was used to determine the particle size distributions (PSDs) of ZnO nanoparticles spiked in soil suspensions. Before FlFFF analysis, the soil was prepared in suspension form, shaken overnight and gravitationally settled to extract the <1-µm fraction. The effect of aging was also investigated using soil samples incubated with known concentrations of ZnO nanoparticles for 7 and 14 days. The results show that FlFFF can be used to determine the PSD of engineered nanoparticles and monitor their partitioning and stability in soil suspensions.

Selective determination of Triton-type non-ionic surfactants in different samples by on-line clean-up and FIA

1990 ◽  
Vol 337 (4) ◽  
pp. 389-392 ◽  
Author(s):  
M. E. Le�n-Gonzalez ◽  
M. J. Santos-Delgado ◽  
L. M. Polo-D�ez
Keyword(s):  
Ionic Surfactants ◽  
Selective Determination ◽  
On Line

Dry Ashing Preparation of (Quasi)solid Samples for the Determination of Inorganic Elements by Atomic/Mass Spectrometry

2015 ◽  
Vol 50 (4) ◽  
pp. 304-331 ◽  
Author(s):  
Kun Shen ◽  
Ni Zhang ◽  
Xiaoming Yang ◽  
Zhongxi Li ◽  
Ying Zhang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Atomic Mass ◽  
Inorganic Elements ◽  
Solid Samples ◽  
Dry Ashing ◽  
Atomic Mass Spectrometry

scholarly journals Mechanism of tubulin–colchicine recognition: a kinetic study of the binding of the colchicine analogues colchicide and isocolchicine

1997 ◽  
Vol 327 (3) ◽  
pp. 685-688 ◽  
Author(s):  
Chantal DUMORTIER ◽  
Qunying YAN ◽  
Susan BANE ◽  
Yves ENGELBORGHS
Keyword(s):  
Rate Constant ◽  
Total Concentration ◽  
Carbonyl Oxygen ◽  
Protein Fluorescence ◽  
Kinetic And Thermodynamic Parameters ◽  
Methoxy Groups ◽  
Displacement Experiments ◽  
Absorbance Changes ◽  
Initial Binding

Colchicide (IDE) is a colchicine (COL) analogue in which the C-10 methoxy group is replaced by a hydrogen atom. Its binding to tubulin is accompanied by a quenching of the protein fluorescence. The fluorescence decrease shows a monoexponential time dependence. The observed rate constant increases in a non-linear way with the total concentration of IDE, allowing the determination of a binding constant for an initial binding site (K1 = 5300±300 M-1) and the rate constant for the subsequent isomerization (k2 = 0.071±0.002 s-1) at 25 °C. The rate constant, k-2, for the reversed isomerization can be determined by displacement experiments. Despite the minor alteration of the C-ring substituent, the kinetic and thermodynamic parameters of binding are substantially different from those of COL itself, for both steps. In isocolchicine (ISO) the carbonyl oxygen atom and the methoxy groups of the C-ring have been interchanged. Its binding to tubulin only results in small fluorescence and absorbance changes. Therefore competition experiments with MTC [2-methoxy-5-(2ʹ,3ʹ,4ʹ-trimethoxyphenyl)-2,4,6-cycloheptatrien-1-one] were performed. ISO competes rapidly and with low affinity with MTC. Fluorimetric titrations of tubulin with MDL (MDL 27048 or trans-1-(2,5 dimethoxyphenyl)-3-[4-(dimethylamino)phenyl]-2-methyl-2-propen-1-one) in the presence and absence of ISO give evidence for the existence of a second, slow-reacting low-affinity site for ISO that is not accessible to MTC or MDL. The relevance of these results for the recognition of COL is analysed.

scholarly journals Single–motor mechanics and models of the myosin motor

2000 ◽  
Vol 355 (1396) ◽  
pp. 441-447 ◽  
Author(s):  
T. Yanagida ◽  
S. Esaki ◽  
A. Hikikoshi Iwane ◽  
Y. Inoue ◽  
A. Ishijima ◽  
...  
Keyword(s):  
Single Molecule ◽  
Atp Hydrolysis ◽  
Accurate Determination ◽  
Step Size ◽  
Single Molecule Level ◽  
Detection Techniques ◽  
Myosin Motor ◽  
Mechanochemical Coupling ◽  
Chemical Events

Recent progress in single–molecule detection techniques is remarkable. These techniques have allowed the accurate determination of myosin–head–induced displacements and how mechanical cycles are coupled to ATP hydrolysis, by measuring individual mechanical events and chemical events of actomyosin directly at the single–molecule level. Here we review our recent work in which we have made detailed measurements of myosin step size and mechanochemical coupling, and propose a model of the myosin motor.

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