CC lab 4 Flashcards
is transmitted via electromagnetic waves that are characterized by their freq and wavelength
Energy
describes the relationship between concentration and absorbed light.
Beer’s Law
“the effect of a substance present in the sample that alters the correct value of the result, usually expressed as concentration or activity, for an analyte.”
Interference
can be defined as the application of instruments, in the form of systems or devices, to accomplish some specific objective in terms of measurement of control and sample.
Instrumentation
liquids (reagents, diluents, and samples) are pumped through a system of continuous tubing. Samples are introduced in a sequential manner, following each other through the same network. A series of air bubbles at regular intervals serve as separating and cleaning media.
Continuous flow
Photometer and spectrophotometer relies on measurement of light by a _________
Photodetector
light intensity is measured detection of light is based on the same principle as photometer.
Spectrophotometer
are used in a variety of settings, including small clinics, research
labs, and high-throughput hospital laboratory
Clinical chemistry analyzers
A visible lamp produces light of wavelengths from
400 nm (violet
light) to 700 nm (red light)
is the separation of each sample and accompanying reagents in a separate container.
Discrete analysis
hemoglobin that has leaked from red blood cells and produces pale red to cherry red in color.
Hemolysis
comprises of a light source, a light filter for isolation of a range of wavelengths, sample holder cell, photoelectric detector and lastly a recording
device. The current response of the photoelectric cell is dependent on the light reaching the cell.
Photometer
A typical light source generates a broad range of wavelengths of light.
lamp
Chemical reactions of analyte produce products that can be detected using optical methods which includes (2)
changes in light absorbed
scattered or emitted by the products
it is the use of various control systems for operating equipment’s
and other applications with minimum human intervention.
Automation
The quantitation of analytes is typically based on one of two measurement principles: (2)
- measurement of light (Photometry or Spectrophotometry)
- measurement of electrochemical potential (Potentiometry).
states that the concentration of unknown substance is directly proportional to the absorbed light and inversely proportional to the amount of transmitted light (% transmittance).
Beer-Lambert Law or Beer’s Law
the presence of excess or high levels of bilirubin in serum or plasma which appears bright yellow to dark yellow.
Icteric
they are also used at the point-of-care, such as in physicians’
offices and patient bedsides.
Clinical chemistry analyzers
is the amount of light absorbed, proportional to the inverse log of transmittance
ABSORBANCE /OD
There are three basic approaches with instruments:
- continuous flow
- centrifugal analysis,
- discrete analysis.
universally used in a broad wavelength range from UV to visible to infrared.
Spectrophotometer
corrects absorbance caused by the color of reagents the absorbance of reagents is automatically subtracted from each of unknown reading.
Reagent Blank
is the distance between two successive peaks and it is expressed in terms of
nanometer(nm).
Wavelength
An ultraviolet lamp produces light of wavelengths from about
200
to 400 nm
3 most common endogenous interferents in a serum or plasma sample:
Hemolysis
Ecteric
Lipemic
The other is to measure the rate of change in product formed over time
Rate Reaction
When an analyte is detected using a chemical reaction,
there are two options for assessing its concentration.
End point Reaction
Rate Reaction
run assays on clinical samples such as blood serum, plasma,
urine, and cerebrospinal fluid
Clinical chemistry analyzers
in these systems, samples and reagents are passed sequentially through the same analytical pathway and separated by means of air bubbles.
I-Continuous flow
is a term that describes a correction for background constituents that contribute directly to the signal being measured.
Blanking
Types of Blanking:
Reagent Blank
Sample Blank
is ‘’the replacement of human manipulative effort and facilities in
the performance of a given process by mechanical and instrumental
devices that are regulated by feedback of information so that an
apparatus is self – monitoring or self-adjusting’’.
-The international Union of Pure and Applied Chemistry (IUPAC)
Automation
are especially suitable for chemical reactions that are completed in a relatively shorttime and are “stoichiometric,” meaning that they produce one
product molecule or complex for each moleculeof analyte
End point reaction
One is to wait until the reaction is complete and the total amount of analyte is converted to product
End point reaction
As the amount of a substance in the solution increases, the relative amount of light that passes through solution and reaches the photodetector _____.
decreases
measures absorbance as a function of wavelengths
Spectrophotometer
extremely high triglycerides that make the sample turbid or cloudy
Lipemic
analyzers offer random access, or stat, capabilities.
Discrete analyzers
the ratio of transmitted light divided by incident light on the sample
Percent transmittance
(%T)
measures absorbance of the sample and reagent in the absence of the end product, and corrects the measurement for optical interference (like hemoglobin) absorbing the wavelength of measurement.
Sample blank
makes use of a sophisticated wavelength isolation device called a monochromator.
Spectrophotometer
To select the desired wavelength from the spectrum of light
produced by the light source, a device called ______ or ____ are used
monochromator or
filters
It mathematically establishes the relationship between concentration and absorbed light
Beer-Lambert Law or Beer’s Law
is based on how fast a fixed amount of substrate is converted to product.
commonly observed in enzymatic tests where the substrate convert a numbers of reagent molecules to product. The more enzyme present,
the faster the conversion, the difference between the initial and final
reading represents the concentration of the analyte.
Rate Reactions
Percent Transmittance
%T= transmitted light / incident light
(A= - log T or - log I/I0) T = I/I
is based on measurement of an electrical potential between two electrodes.
Potentiometry
have the capability of running multiple tests one sample at a time or multiple samples one test at a time.
Discrete analyzers
2 electrodes
Sensing
Reference
