Bio

PDF Upload: 

Publications


Submitted

Shiundu, PM, Munguti SM, Williams KRS.  Submitted.  Practical implications of ionic strength effects on particle retention in thermal field-flow fractionation. AbstractPractical implications of ionic strength effects on particle retention in thermal field-flow fractionation

Modification of ionic strength of an aqueous or non-aqueous carrier solution can have profound effects on the particle retention behavior in thermal field-flow fractionation (ThFFF). These effects can be considered as either advantageous or not depending on the performance criteria under consideration. Aside from the general increase in retention time of particulate material (latexes and silica particles), our experiments indicate improvement in resolution with increases in electrolyte concentration. Absence of an electrolyte in the carrier solution causes deviations from the theoretically expected linear behavior between the retention parameter l (a measure of the extent of interaction between the applied field and the particle) and the reciprocal temperature drop across the channel walls. A negative interaction parameter d of about 20.170 was determined for 0.105- and 0.220-mm polystyrene (PS) latex particles suspended in either a 0.25 or a 1.0 mM TBAPcontaining acetonitrile carrier and for 0.220 mm PS in 0.50 and 1.0 mM NaCl-containing aqueous medium. This work also demonstrates that optimum electrolyte concentrations can be chosen to achieve reasonable experimental run-times, good resolution separations, and shifts in the steric inversion points at lower field strengths, and that too high electrolyte concentrations can have deleterious effects such as band broadening and sample loss through adsorption to the channel accumulation surface. The advantages of using ionic strength rather than field strength to effect desired changes are lowered power consumption and possible application of ThFFF to high temperature-labile samples.

M, PROFSHIUNDUPAUL.  Submitted.  Wilson G. Kamundia, Paul M. Shiundu, and John M. Onyari, . Federation of Analytical Chemistry and Spectroscopy Society (FACSS) XV, Boston, November 1988. : AWC and FES Abstract
n/a
M, PROFSHIUNDUPAUL.  Submitted.  Patrick M. Shem, Paul M. Shiundu, Nicholas K. Gikonyo, Ahmed Hasssanali and Rajinder K. Saini, . Federation of Analytical Chemistry and Spectroscopy Society (FACSS) XV, Boston, November 1988. : AWC and FES Abstract
n/a
M, PROFSHIUNDUPAUL.  Submitted.  Patrick M. Shem, Paul M. Shiundu, Nicholas K. Gikonyo, Ahmed Hasssanali and Rajinder K. Saini, . Federation of Analytical Chemistry and Spectroscopy Society (FACSS) XV, Boston, November 1988. : AWC and FES Abstract
n/a
M, PROFSHIUNDUPAUL.  Submitted.  Wilson G. Kamundia, Paul M. Shiundu, and John M. Onyari, . Federation of Analytical Chemistry and Spectroscopy Society (FACSS) XV, Boston, November 1988. : AWC and FES Abstract
n/a

2013

2012

2010

  2010.  Introductory Chemistry 1. AbstractIntroductory Chemistry 1

This module covers introductory topics that are fundamental to understanding the subject of chemistry. In this module, we shall examine the structure of the smallest part of an element known as the atom (the building blocks of matter) and associated atomic models. The focus will be on the thought process involved in the development of the periodic table and its use in explaining the structure and properties of elements in “groups” and “periods”. Both microscopic (in which matter is regarded as a collection of atoms and molecules) and macroscopic (associated with the bulk properties of matter) views of matter will be considered. The underlying principles that govern structures and shapes of simple molecules and ions will be covered as well as the nomenclature for writing formula for binary inorganic compounds, cations and anions. In addition, a review of the concepts behinds interpretation and balancing of chemical equations, stoichiometric calculations involving quantitative relations in chemical reactions, calculations of percent composition by mass and derivation of molecular formula from experimental data will also be made.

2009

Kim, S, Williams R, Cinque L, Shiundu PM.  2009.  Size Determination of Nanoparticles Used in Coatings. AbstractSize Determination of Nanoparticles Used in Coatings

This chapter begins with a description of some commonly used particle sizing techniques, their applicability to nanoparticles, and their advantages and disadvantages. A special emphasis is given to fractionation techniques and their ability to simultaneously characterize nanoparticles and isolate monodispersed fractions from polydispersed samples. The latter part of this chapter provides an in-depth discussion of sedimentation field-flow fractionation (SdFFF) size analysis of nanoparticles used in coatings

2007

Kremmer, E, Krämer PM, Weber CM, Räuber C, Martens D, Forster S, Stanker LH, Rauch P, Shiundu PM, Mulaa FJ.  2007.  Optical Immunosensor and ELISA for the Analysis of Pyrethroids and DDT in Environmental Samples. AbstractOptical Immunosensor and ELISA for the Analysis of Pyrethroids and DDT in Environmental Samples

An optical immunosensor (AQUA-OPTOSENSOR) and ELISA (enzyme-linked immunosorbent assay) for the analysis of pyrethroids and DDT in river water and/or sediment, are described. The optical immunosensor consists of a bench-top optical read-out-device and disposable single-use sensor chips. ELISA was carried out in the coating antigen format. As examples, phenothrin (pyrethroid) and p,p'-DDT were chosen. Herein we describe the overall strategy, the set-up and principle of the immunosensor platform, and show representative results for immunosensor and ELISA analysis. The immunosensor employs fluorophore (Oyster®-645)-labeled monoclonal antibodies (mouse mAb Py-1 and rat mAb DDT 7C12), and makes use of the evanescent field, thus operating without washing steps. ELISA in the coating antigen format uses a second antibody labeled with peroxidase. Both, phenothrin and p,p'-DDT can be analyzed with these immunochemical techniques in the low ppb levels. Advantages and drawbacks of both immunochemical platforms are discussed.

2006

M, PROFSHIUNDUPAUL.  2006.  Benson Munyali Wamalwa; Makiko Sakka; Paul Mwanza Shiundu; Kunio Ohmiya; Tetsuya Kimura; and Kazuo Sakka, . Appl. Environ. Microbiol., 72 (10), 6851-6853. : AWC and FES Abstract
Five plasters and one fiberglass casting bandages available on the Kenyan market were evaluated for breaking strength and resistance to abrasion. Under the test conditions, scotch cast was found to be 2.6 times stronger than the strongest plaster of Paris preparation when the load per unit thickness was compared and was significantly different from the plaster casts in terms of maximum load (p=0.0001). Among the plaster products, there were significant statistical differences (p=0.029) in maximum strength with Helm and Plasrum-gyps withstanding the greatest load. Scotchcast was the most resistant to abrasion while among the plaster product, Salvaplast and POP-Nairobi Enterprises showed satisfactory resistance Heal, Plasrun-gyps and Veronese proved least resistant under the testing conditions.

2005

M, PROFSHIUNDUPAUL.  2005.  Wamalwa, B.M., M. Sakka, P.M. Shiundu, T. Kimura, K. Ohmiya, and K. Sakka, . J. Appl. Glycoscience, 52 Suppl., 49-51. : AWC and FES Abstract
domain of the putative celB gene from alkalophilic Bacillus

2003

M, PROFSHIUNDUPAUL.  2003.  Removal of Cu (II) from an aqueous solution using a micaceous mineral of Kenyan origin, Adsorption Science Technology , 21 (3), 269-283. J. Colloid and Interface Sci., 266(2), 366-376. : AWC and FES Abstract
domain of the putative celB gene from alkalophilic Bacillus
M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  2003.  Retention Behavior of Metal Particle Dispersions in Aqueous and Nonaqueous Carriers in Thermal Field-Flow Fractionation. J. Chromatogr. A., 983, 163-176. : AWC and FES Abstract
domain of the putative celB gene from alkalophilic Bacillus
M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  2003.  Magnitude and Direction of Thermal Diffusion of Colloidal Particles Measured by Thermal Field-Flow Fractionation. J. Colloid and Interface Sci., 266(2), 366-376. : AWC and FES Abstract
domain of the putative celB gene from alkalophilic Bacillus

2002

M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  2002.  Sorption and Detection of Phenolic Compounds by Rice Husk Ash of Kenyan Origin. J. Environ. Monit., 4,978-984. : AWC and FES Abstract
n/a
M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  2002.  Thermal Field-Flow Fractionation for Particle Analysis: Opportunities and Challenges. Polym. Mater. Sci. Eng., 87, 342. : AWC and FES Abstract
n/a
M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  2002.  Factors Affecting Particle Retention in Thermal Field-Flow Fractionation. Bull. Chem. Soc. Ethiop., 16(1),91-101. : AWC and FES Abstract
domain of the putative celB gene from alkalophilic Bacillus

2000

M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  2000.  Thermal Stability Studies on Vernonia Galamensis Seed Oil. Bull. Chem. Soc. Ethiop., 14(2), 161-167. : AWC and FES Abstract
n/a

1998

N, PROFKAMAUGEOFREY, M PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  1998.  Fuel value of Refined vernonia galamensis seed oil". J. Biochemphysics, 6&7, 33.. : AWC and FES Abstract
n/a

1996

M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  1996.  Field-Flow Fractionation: Theory and Practice. Proceedings of the 2nd Theoretical Chemistry Workshop in Africa held on 26th-30th August, 1996, Nairobi, Kenya.. : AWC and FES Abstract
n/a
M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  1996.  Isolation and Characterization of Polymeric and Particulates of Acrylonitrile-Butadiene-Styrene (ABS) Plastics by Thermal FFF.. J. Appl. Polym. Science., 60, 1695-1707. : AWC and FES Abstract
n/a

1995

M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  1995.  Size and Composition Studies of Core-Shell Latexes Using Flow and Thermal Field-Flow Fractionation. Colloids Surfaces A: Physicochemical and Engineering Aspects., 105, 243-250,. : AWC and FES Abstract
n/a
M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  1995.  Thermophoresis of Metal Particles in a Liquid.", J. Colloid and Interface Science, 176, 454-458,. : AWC and FES Abstract
n/a
M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  1995.  Influence of Bulk and Surface Composition on the Retention of Colloidal Particles in Thermal Field-Flow Fractionation.. J.Chromatography A., 715, 117-126. : AWC and FES Abstract
n/a
M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  1995.  Separation of Particles in Nonaqueous Suspensions by Thermal Field-Flow Fractionation. Anal. Chem., 67, 2705-2713,. : AWC and FES Abstract
n/a

1994

1992

M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  1992.  Spectrophotometric Method for Determination of Sulfide with Iron(III) and Nitrilotriacetic Acid by Flow Injection. Talanta, 39(3), 299-312. : AWC and FES Abstract
n/a

1991

M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  1991.  Development of Catalytic Photometric Flow Injection Methods for Determination of Selenium. Anal. Chem., 63, 692-699,. : AWC and FES Abstract
n/a
M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  1991.  Versatile IEEE-488 Data Acquisition and Control Routines for Diode Array Spectrophotometer. J. Automatic Chem., 13(3), 83-92,. : AWC and FES Abstract
n/a

1990

M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  1990.  "Automated Exploration and Exploitation of Flow Injection Response Surfaces. Anal.Chim.Acta, 237, 361-379. : AWC and FES Abstract
n/a
M, PROFSHIUNDUPAUL.  1990.  P.M. Shiundu* and A.P. Wade: . Federation of Analytical Chemistry and Spectroscopy Society (FACSS) XVII, Cleveland, October 1990.. : AWC and FES Abstract
n/a
M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  1990.  Spectrophotometric Determination of Peroxydisulphate With o-Dianisidine by Flow Injection.",. Can.J.Chem., 68, 1750. : AWC and FES Abstract
n/a
M, PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL, M PROFSHIUNDUPAUL.  1990.  Spectrophotometric Determination of Palladium(II) ions with Sulphochlorophenolazorhodanine by Flow injection. Talanta, 37, 329. : AWC and FES Abstract
n/a

1989

1988

M, PROFSHIUNDUPAUL.  1988.  P.M. Shiundu, A.P. Wade, P.D. Wentzell, and J.A. Horner: . Federation of Analytical Chemistry and Spectroscopy Society (FACSS) XV, Boston, November 1988. : AWC and FES Abstract
n/a

UoN Websites Search