Intro to Chem and Analytic Methods Flashcards

1
Q

Spectrophotometry

A

is a method to measure how much a chemical substance absorbs light by measuring the intensity of light as a beam of light passes through sample solution. The basic principal is that each compound absorbs or transmit light over a certain range of wavelength.

Consist of two devices; a spectrometer and a photometer.

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2
Q

Spectrometer

A

a device that produces, typically disperses and measures light.

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3
Q

What is clinical chemistry?

A

The soluble mediators that are in the liquid potions of the body.

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4
Q

True or False: We only use serum for a lot of our tests.

A

False. We have newer methods that allows us to use both serum and plasma for a lot of our tests.

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5
Q

What is an advantage of using plasma over serum?

A

You don’t have to wait the 30 minutes for plasma like you need to for serum. So you don’t need to worry about waiting for a specimen to clot before spinning it and test it quicker.

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6
Q

True or False: We use chemistry to evaluate acid base balance, electrolyte and water abnormalities.

A

True

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7
Q

True or False: one test can tell you what’s going on with a patient.

A

False: one test will not tell you what’s going on with a patient.

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8
Q

What is metabolic disease?

A

Is an all encompassing diagnosis of somebody who’s overweight and out of shape, and showing evidence of disequilibrium in a test.

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9
Q

What is the number one cause of metabolic disease in the western world?

A

Obesity

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10
Q

What would be the primary cause of a person dying from a heart attack?

A

Metabolic disease.

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11
Q

True or False: Liver disease is rare.

A

False: Liver disease is very common. In the lab we see both acute and chronic phases of liver disease.

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12
Q

When looking at liver disease in patients, what are we looking for in the lab?

A

We are looking at enzymes and byproducts of liver detoxification.

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13
Q

True or False: if a disease is present, we would want to see elevations in different biomarkers.

A

True.

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14
Q

True or False: renal disease can only be chronic.

A

False. There is bother acute kidney disease and chronic renal disease

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15
Q

Acute kidney disease vs. chronic

A

In acute, we see inflammation in the tissue. In chronic conditions, there is scar tissue being present and it’s only taking up space and not being functional.

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16
Q

True or False: Diabetes has similar biomarkers as kidney disease.

A

True. Diabetes you have the inability to store glucose, so your body redirects that glucose into your kidneys, and over time your kidneys become unable to cope with that extra glucose.

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17
Q

What does a BMP stand for and what does it compose of?

A

Basic Metabolic Panel. It is compose of Glucose, Albumin, Total Protein, Sodium, Potassium, Chloride, BUN (Blood Urea Nitrogen), Creatinine, and CO2. (9+)

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18
Q

What does CMP stand for and what does it compose of?

A

Complete Metabolic Panel. It is compose of a BMP with a liver panel. The liver panel includes Alanine Aminotransferase (ALT), Aspartate Aminotransferase (AST), Alkaline Phosphatase (ALP), and Total Bilirubin. (4+)

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19
Q

What test will be affected by fasting?

A

Glucose and triglycerides

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20
Q

What is the Matrix?

A

Matrix is a specimen type that we use. The matrix that we are using for testing is typically plasma or serum. Matrix can also be urine, feces, and other body fluids.

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21
Q

How is the matrix tested?

A

Every single test undergoes a unique reaction with a unique reagent. Reaction produce by a color change by the reagent and compound in question. Color change will either be directly or inversely proportional to the concentration of the unknown, given a standard concentration. We used closed systems and ultimo focused light spectra in quantitating color change of the reaction.

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22
Q

True or False: Photometric instruments measure light intensity without consideration of wavelength.

A

True, most instruments use filters (photometers), prisms, or gratings (spectrometers) to select (isolate) a narrow range of incident wavelength.

23
Q

Explain the principles of Beer’s Law

A

Concentration of a substance is directly proportional to right amount of light absorbed or inversely proportional to logarithm of transmitted light.

24
Q

What is the function of spectrophotometric instruments?

A

measure light transmitted by a solution to determine concentration of light-absorbing substance in solution

25
Q

Components of a Spectrophotometer

A

Light source, Monochromators, Sample cell, Photodetectors

26
Q

True or False: we need to do spectrophotometer quality assurance

A

True, we need to check wavelength accuracy, stray light, linearity, and sensitivity (make sure none is off).

A well maintained analyzer works better.

27
Q

What color has a measurement of 400 nanometers?

A

Violet

28
Q

What color has a measurement of 700 nanometers?

A

Red

29
Q

What is Electromagnetic radiation?

A

is described as protons of energy traveling in waves.

30
Q

Describe the operation of a Spectrophotometer

A

You have a light source, it goes through a little entrance slit (controlling where and how it blocks out stray light), then it goes to a dispersion device (breaking the beam up into the various wavelengths), afterward that there is an exit slip (it controls what wavelength gets through, the wavelength goes through your sample, and through a detector.

31
Q

What is the function of Light Source in spectrophotometry?

A

A light source produces an intense, reproducible and constant beam of light.

You don’t want it to flicker or not be steady. There are two type of lamps: tungsten lamp (visible and infrared red regions) and deuterium (ultraviolet region.)

32
Q

True or False: any time a lamp is changed in a spectrophotometer, the instrument has to be recalibrated.

A

True. Changing the light source, changes the angle that the light is striking that monochromatic device.

33
Q

What are the components of spectrophotometer components?

A

Light source, Monochromator, Corvettes, Light Detectors, Read-out Systems

34
Q

What is the function of Monochromator in spectrophotometry?

A

It splits white light into various wavelengths.

There are different types: Glass filters, interference filters, diffraction gratings, or prisms.

35
Q

What is the function of Curvettes in spectrophotometry?

A

Light is absorbed by the solution and then the rest of it will be transmitted.

36
Q

What are percent transmittance (%T)?

A

the ratio of the radiant energy transmitted divided by the rated energy incident on the sample.

%T = (sample beam signal / blank beam signal) x100

Radient Energy transmitted is T.

37
Q

True or False: If all of the light is absorbed or blocked, you get 0% transmittance

A

True, because no light made it through.

38
Q

If you have a level of 100% transmittance was obtain, would light be absorbed?

A

no light would be absorbed

39
Q

If we have 5 layers. If 70% of light is transmitted on the first layer, what do you end up with?

( to get to the second layer, what is 70% of 70? Then multiple that by 70% (3rd layer). Then multiple that by 70% (4th layer). and by 70% (5th layer.)

So if you have five layers at 70% transmission, you end up with ____ of transmittance.

A

49%, 34%, 24%, 17%.

You end up with 17% of transmittance.

40
Q

Photodetectors *** ( needs to be edited 1:15

A

Sector that measures the intensity of light.

Light will pass a sample and hits the photocell and goes to the emitter. Typically kept in the dark, except for where that light is coming in. It has a cathode emitter that is typically made of selenium and that responds to photons of light and generates electrons. Those travel through conduit lines. The more light that goes through the emitter, the more electrons are generated and it hits the voltmeter and that picks up the electrons that are produced. It is self propelling energy, but it doesn’t do a great home with low amounts of light. Not very sensitive. Okay with things with low concentrations, for large amounts of light is going to get through. And there is no power source on it.

Phototube has an external power supply, so it gives it a little more based on current, and it’s better with smaller amounts of light. Has a photosensitive material that gives off electrons when light energy hits it. (has to have that outside voltage, so it has some sort of power supply). Typically there is a vacuum that avoid scattering photo electrons by collision with gas.

Example: photocell (basic) and vs phototube. We are going to use a photomultiplier

41
Q

Photomultipler

A

Major type of photodetector. It detects and amplifies radiant energy.

Photomultiplier is 200X more sensitive that the phototube, because it can amplify radiant energy. They are designed to be extremely sensitive to very low light levels and light flashes that are very short durations.

42
Q

Dynodes

A

are a series of anodes with successfully higher voltage and the light gets converted into electrons, into amperes (amps), into volts, and then into absorbance.

43
Q

Differential filter

A

The purpose of a differential filter is to get ride of any interference substances, in order to give you an accurate sample.

44
Q

Wavelength

A

Wavelength is the distance traveled by one complete wave cycle and is measured in nanometers.

45
Q

Wavelength accuracy

A

the wavelength that it says on the setting is actually that the wavelets that’s coming out.

The way it’s checked is typically using standard absorbing solutions or filters that will absorb wavelengths

46
Q

Stray light effect

A

refers to any wavelength outside of the fan transmitted by the mode of the matter

47
Q

Linearity

A

demonstrated when we have a change in concentration, results in a straight line.

48
Q

Atomic Absorption spectrophotometry ** (for sure test question)

A

It is used to measure concentration by detecting the absorption of electromagnetic radiation by atoms rather than by molecules.

49
Q

Fluorometry

A

Uses fluorescence to determine concentration of an analyte.

Adv: specificity and sensitivity
disadvantage: pH, temp

50
Q

Chemiluminescence

A

The emission of light by molecules in excited states produced by chemical reactions.

Adv: sudbpicomolar detections limits (very very sensitive), speed, ease of use, simple instrumentation, no excitation radiation required an no monochromators

Disadvantage: impurities can cause a background signal that degrades the sensitivity and specificity. More calibrations.

51
Q

Turbidimetry

A

Made with a spectrophotometer to determine the concentration of particulate matter in a sample.

Measurement of the amount of light that can pass through a sample at a 180 angle from the incident light.

Sample handling is critical for accurate measurement.

52
Q

Nephelometry

A

Technique that measured scattered light by placing a detector at a 90 angle from the incident light

Minimizes errors from colored solutions and increases sensitivity

53
Q

What is the function of Light Detectors in spectrophotometry?

A

Converts light to electric signal

54
Q

What is the function of Read-out Systems in spectrophotometry?

A