Micro‐ and Frontal Thermal Field‐Flow Fractionation: On the Shear Degradation of Ultra‐high Molar Mass Polymers

2004 ◽  
Vol 27 (2) ◽  
pp. 193-214 ◽  
Author(s):  
Josef Jan[cbreve]a ◽  
Petr Strnad
Keyword(s):  
Thermal Field ◽  
Molar Mass ◽  
Field Flow Fractionation ◽  
High Molar Mass ◽  
Shear Degradation ◽  
Flow Fractionation ◽  
High Molar Mass Polymers

Assessment of metal - extracellular polymeric substances interactions by asymmetrical flow field-flow fractionation coupled to inductively coupled plasma mass spectrometry

2010 ◽  
Vol 7 (2) ◽  
pp. 215 ◽  
Author(s):  
Enrica Alasonati ◽  
Stephane Dubascoux ◽  
Gaetane Lespes ◽  
Vera I. Slaveykova
Keyword(s):  
Mass Spectrometry ◽  
Flow Field ◽  
Inductively Coupled Plasma ◽  
Extracellular Polymeric Substances ◽  
Molar Mass ◽  
Field Flow Fractionation ◽  
High Molar Mass ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry ◽  
Flow Fractionation

Environmental context. Extracellular polymeric substances (EPS) are soluble polymers that are liberated from microorganisms and represent an important component of the natural organic matter in the aquatic and terrestrial environment. These substances affect nutrient and toxic metal cycling, both owing to their metal binding properties and their effect on aggregation and sedimentation. In order to obtain more information on their role in metal transport, EPS size (molar mass) distributions and the associated Ca, Cd and Pb were measured by using asymmetrical flow field-flow fractionation coupled to inductively coupled plasma mass spectrometry. Abstract. Extracellular polymeric substances (EPSs) excreted by the bacterium Sinorhizobium meliloti and associated Ca, Cd and Pb were characterised by asymmetrical flow field-flow fractionation coupled with UV spectrophotometry and inductively coupled plasma mass spectrometry in terms of molar-mass distributions, number- and weight-average molar masses and polydispersity index. Two major populations with weight-average molar masses of 74 × 103 and 1.35 × 106 g mol–1 were obtained for the EPS. Characterisation of the whole EPS–metal interactions evidenced the preferential binding of Ca and Cd to the low molar mass fraction, whereas Pb associated mainly with the high molar mass (HMM) fraction. Comparison with the EPS produced by exoY-mutant, deficient in HMM-EPS excretion, confirmed the preferential binding of Pb to the high molar mass fraction. Enrichment of the EPS with increasing metal concentrations induced the formation of aggregates, which was most pronounced in the presence of 10–4 mol L–1 Pb.

Micro-Thermal Field-Flow Fractionation

2002 ◽  
Vol 67 (11) ◽  
pp. 1596-1608 ◽  
Author(s):  
Josef Janča
Keyword(s):  
High Performance ◽  
Thermal Field ◽  
Temperature Drop ◽  
Point Of View ◽  
Constant Field ◽  
Field Flow Fractionation ◽  
Operational Mode ◽  
Experimental Conditions ◽  
Standard Size ◽  
Flow Fractionation

The effect of miniaturization of the separation channel on the performance of thermal field-flow fractionation (TFFF) is substantiated theoretically. The experiments carried out under carefully chosen experimental conditions proved the high performance of the separation of polymers within an extended range of molar masses from relatively low up to ultrahigh-molar-mass (UHMM) samples. The new micro-TFFF allows to achieve high resolution when applying constant field force operation, it makes easy the programming of the temperature drop which is an advantageous operational mode from the point of view of the time of analysis, and it extends considerably the range of perfectly controlled temperature of the cold wall due to a substantial decrease in the heat energy flux compared with standard size channels.

Molar Mass Characterization of Crude Lignosulfonates by Asymmetric Flow Field-Flow Fractionation

2018 ◽  
Vol 7 (1) ◽  
pp. 216-223 ◽  
Author(s):  
Irina Sulaeva ◽  
Philipp Vejdovszky ◽  
Ute Henniges ◽  
Arnulf Kai Mahler ◽  
Thomas Rosenau ◽  
...  
Keyword(s):  
Flow Field ◽  
Molar Mass ◽  
Field Flow Fractionation ◽  
Asymmetric Flow ◽  
Flow Fractionation
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