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DETERMINATION OF ETHANOL FOR PROCESS AND QUALITY CONTROL USING FLOW INJECTION ANALYSIS
No full textFlow injection analysis was used to determine ethanol in beverages, pharmaceutical products
and fermentation media without the requirement for sample pretreatmentor dilution. The sensitivity
of the assay was modified by the thickness of a gas diffusion layer. The cost per sample (20 assays)
was 1.5 Pfennig (DM 0.015). The frequency of analysis was 120-180 assays per hour, making it
suitable for the on-line monitoring of fermentation processes. Samples of wine, beer, spirits,
medicine and fermentation broth were tested and a goodcorrelation to the standard methods was
obtained
IMAGING OF LASER-INDUCED FLUORESCENCE EMITTED BY TUMOR LOCALIZING PHOTOSENSITIZERS
No full textPhotodynamic therapy is an experimental modality for the destruction of tumors or
tumor cells by photochemical processes /1,2/. Such reactions are induced by exciting
tumor-localizing photosensitizers by visible laser light. In addition to
therapeutical applications, the characteristic fluorescence of the excited
photosensitizers can be used for diagnostic purposes, i.e. for localization and
imaging of tumors. The detection of small tumors as well as the determination of the
extent of the lesion sensitively depend on the discrimination between sensitizer and
tissue autofluorescence. This is particularly important at the boundary between tumor
and normal tissue
BIOSENSORS IN INDUSTRY : WHAT DO WE EXPECT ?
No full textIn this article possible applications of biosensors to industrial
process control in the field of biotechnology, eco-biotechnology and
environmental control are discussed. If some of the ideas, opinions
and concepts are applicable to other fields, such as medicine or food
industry is beyond of the authors experience.
In spite of the fact, that biotechnological processes are in many
cases not fully understood novel analytical techniques, such as biosensors,
are not accepted and therefore not used in industrial analytical
laboratories or for process control. Solutions for actual
problems are tried to be found by internal experts, applying sophisticated,
well established and well known techniques. In fact, there
often does not (yet) exist a scientific and/or commercial pressure to
strongly reduce batches which do not meet all specifications. In addition,
improvements in product yield is considered to depend mainly
on molecular biology.
Therefore the introduction of biosensors in an industrial environment
is only possible if they present a well adapted solution for a
very important analytical problem.
These facts lead to an unproven benefit of applying modern analytical
techniques such as new (bio)sensors and control instrumentation.
Consequently analytical instrument companies have no commercial interest
to develop and sell highly sophisticated analytical systems
for industrial bioprocess control
On Line Determination of Glucose Concentration in Animal Cell Cultures Based on Chemiluminescent Detection Coupled with Flow Injection Analysis
No full textA flow injection analysis (FIA) system for the on-line determination of glucose in animalcell cultures is
described. The hydrogen peroxide generated in the enzyme reaction is determined via a highly sensitive
chemiluminescent reaction with luminol. Based on the measurement of the maximum emitted light intensity,
the system was able to analyse glucose in a linear range of 10° to 5x 102 M glucose concentration, with
an r.s.d. of 3% at the 1 mM level (5 measurements). The enzyme reactor used was stable for more than
4 weeks in continous operation. The FIA developed wasable to analyse up to 20 samples per hour. The
system has been sucessfully applied to on-line monitoring of glucose concentration during an animal cell
culture, designed for the production of human antithrombin III factor. Results obtained with the FIA
system were compared with off-line results, obtained with a Yellow Springs Instrument Company Model27
(YSI)
ENZYME-CATALYZED DETERMINATION OF 2-OXOISOCAPROATE BY FLOW-INJECTION ANALYSIS AND ITS APPLICATION TO THE MONITORING FOR MAPLE SYRUP URIN DISEASE
No full textA simple and fast method for the determination of 2—oxoisocaproate in plasma samples by
use of NAD*-dependent D-2-hydroxyisocaproate dehydrogenase (Hic-DH) from
Lactobacillus casei ssp. is described. The enzyme is immobilized on aminopropyl-CPG
and applicated in a flow-injection system with detection of NADH absorbance.
Applicability is demonstrated by comparative measurement of 2-0xoisocaproate levels in
plasma samples of patients with maple syrup urine disease by the photometric method
and the flow-injection analysis
SIMULTANEOUS FLOW INJECTION DETERMINATION OF MALATE AND ETHANOL BASED ON OXYGEN CONSUMPTION WHITH DEHYDROGENASE AND OXIDASE REACTORS
No full textThe simultaneous determination system of L-malate and ethanol was
developed by using two enzyme reactors in parallel and a single oxygen
electrode. NADH formed in the reaction of malate dehydrogenase was regenerated
to NAD with dissolved oxygen using vitamin K; and diaphorase.
Ethanol was determined by use of alcohol oxidase. When a sample solution
was simultaneously injected to two reactors, a train of two peaks
corresponding to ethanol and L-malate appeared in an FIA-gran. The
peak current was linearly related to ethanol and L-malate concentration
in the range 18-50 mM and 0.09-0.9 mM, respectively. The present system
was applicable to the determination of ethanol and L-malate in wine
FIA-SYSTEMS FOR THE DETERMINATION OF MALTOSE, LACTATE AND VOLATILE SUBSTANCES IN BEER, WINE AND FERMENTATION BROTHS
No full textFIA-systems with immobilized enzymes for analysis of substrates in biological matrices are
described. Direct or coupled reactions lead to the commonproduct NADH, which is
determined byfluorimetry. The flow systems imply modulesfor the purification, dilution and
pH adjustment of the samples. A system is presented for the determinationof volatile
substrates using pervaporation as sample purification. Applications for the quantification of
ethanol in beer (measurable range 0.5 - 20 mM) and acetaldehyde in wine (measurable
range 0.01 - 0.05 mM) are given. By automated switching of the analyte between parallel
assembled dehydrogenase columnsthe control of ethanol (calibration range 0.03 -10 mM)
and lactate (calibration range 0.01 - 10 mM)in a fermentation of Clostridium
thermohydrosulfuricum is possible. The determinations show goodreproducibility and
Satisfactory agreement with results of a common enzymatic test-kit. A more sophisticated
experimental setup including ion exchange and dialysis as purification steps is developedfor
cyclic/parallel determination of glucose, maltose(linear range 0.3 - 15 mM for both sugars)
and ethanol(linear range 6 - 500 mM)in beer. Process stability of the enzymes proved to be
Satisfying
DETERMINATION OF BOD USING A FIA SYSTEM WITH MICROBIAL SENSOR
No full textA microbial amperometric sensor for the determination of the
biochemical oxygen demand using Trichosporan cutaneum cells immmobilized
in polyvinyl alcohol has been developed. The sensor has a response time
of less than 1 min. A linear range is obtained up to 100 mg /1 BOD in
the sample. For calibration a glucose/glutamic acid standard is used.
A dilution of the waste water is necessary for practical application.
Therefore a FIA system was coupled with the BOD sensor. In this way it
is possible to analyse waste water up to 1000 mg 1 BOD with a serial
coefficient of variation below 5 percent
FIBER OPTIC SENSORS: CURRENT STATUS
No full textBiosensors are attracting the attention of manyinvestigatorsin the field of
biotechnology related research. A biosensoris a device that combinesthe specificity of a
biomaterial (enzymes, antibodies, receptors or even whole cells) with sensitive, well
established bioassays. Biosensors are of potential use in manyfields includingclinical and
biotechnology monitoring. An importantclass of enzymes, effecting H,O, generation or O7
depletion, can be monitored by following the enzymatic reaction, and thus determining the
substrate level. Other enzyme systems, like urease andpenicillinase,result in a pH change
which can be followed using a pH sensitive device. For the many advantagesoffiber optic
sensing, extensive research efforts have been devoted to the productionofreliable,selfcontained
andsensitive fiber optic biosensors which are capable of in situ monitoring. An
overview ofthe possibilities and challenges associated with the construction of such sensors
are discussed
ALGAE TOXIMETER - A BIOSENSOR FOR WATER MONITORING
No full textAn algae toximeter - a novel automated biosensor - is presented that is applied
as a rapid indicator of herbicides in rivers, lakes and waste water. The apparatus
functions continously in the control station and transmits the measuring
results via data telecommunication to a host computer. The opto-electronic unit
of the biosensor detects immediately the chlorphyl]l-fluorescence emission from
the algae which have been contaminated by the water being tested. Due to the
influence of substances in the water which are toxic to algae, in particular due
to the influence of herbicides (electron transport blockers), a measurable
increase in the chlorophyll-fluorescence emmision can be observed. This apparatus
can also be used, as a laboratory version, in the screening to exotoxicological
substances