BASIC PRINCIPLES OF INSTRUMENTATION AND AUTOMATION

 Spectrometry
 Luminescence
 Electroanalytic
 Chromatography

Spectrometry and photometry

Photometric instruments
Planck’s formula E=hv

Beers law

The concentration of a substance is directly proportional to right amount of light

absorbed or inversely proportional to logarithm of transmitted light

T= transmittance
=%T I/Io x 100

%T= 100 = no light absorbed

%T 0 = light absorbed

Infrared region
Incandescent tungsten or tungsten-iodide

Monochrometer
Diffraction gratings
- 15,000- 30,000 parallel groobes per inch
 Photocell – thin film
Selenium

 Phototube
Rubidium/lithium

 Photomultiplier
200x sensitive

SPECTROMETER QUALITY ASSURANCE

Wavelength
Stray light
linearity

atomic absorption spectrophotometer

The atomic absorption spectrometer is used to measure concentration by detecting
the absorption of electromagnetic absorption

Flame photometry

Fluorometry

Chemiluminescence

Turbidity and nephelometry

Electrophoresis

Ion selective electrode

Measure sa Ph
Indicator

Reference electrode

High performance liquid chromatography (HPLC)

1. Pumps
2. Columns
3. Sample injectors
4. Detectors
5. Recorders

Types of Spectrophotometers
1. Single-beam Spectrophotometer: This type of spectrophotometer
measures the intensity of light before and after it passes through the sample,
using only one beam of light. It is simpler and more cost-effective but may
not be as accurate as other types due to the need for frequent recalibration.
2. Dual-beam Spectrophotometer: A more advanced version that splits the
light into two beams – one passes through the sample while the other passes
through a reference. This allows for more stable measurements as it can
correct for fluctuations in light intensity, making it more accurate than the
single-beam version.
3. Atomic Absorption Spectrophotometer (AAS): AAS is used for detecting
metals in samples by analyzing the absorbed light. It is highly sensitive and is
typically used for trace element analysis, such as measuring lead or mercury
in environmental samples.
4. Flame Photometer: A type of spectrophotometer that is specifically
designed to measure the concentration of certain ions, such as sodium or
potassium, using flame excitation. It’s primarily used in clinical and
environmental laboratories.
5. Fluorometer: Measures the fluorescence (emission of light) of a sample
after it has been excited by a certain wavelength of light. It's used for
detecting very low concentrations of analytes, often in biochemical assays.
6. Chemiluminescence Spectrophotometer: This instrument detects the
light produced from a chemical reaction rather than light absorption. It is
widely used in immunoassays and for detecting very small amounts of
biological molecules.
Each type of spectrophotometer is chosen based on the type of analysis being
performed, the sensitivity required, and the properties of the analyte in question.
4o
You said:
please explain the answers
ChatGPT said:
ChatGPT
Here’s a detailed explanation of the answers for the first 10 multiple-choice
questions:

1. What principle is used in spectrophotometry?

o Answer: B) Beer’s Law

o Explanation: Beer’s Law (or the Beer-Lambert Law) is a fundamental

principle in spectrophotometry. It states that the absorbance of light by
a solution is directly proportional to the concentration of the absorbing
species in the solution. This principle is widely used to determine the
concentration of substances in spectrophotometric analyses.
2. In Beer’s Law, the concentration of a substance is directly
proportional to:
o Answer: C) The amount of light absorbed

o Explanation: According to Beer’s Law, the concentration of a

substance is directly proportional to the absorbance, which is the
amount of light absorbed by the substance. As the concentration
increases, the substance absorbs more light.
3. What type of energy is measured in spectrophotometry?
o Answer: D) Light

o Explanation: Spectrophotometry measures the intensity of light. It is

concerned with how light interacts with matter, specifically how much
light is absorbed or transmitted by a substance.
4. Which type of spectrophotometer uses only one light beam for
measuring sample absorbance?
o Answer: B) Single-beam

o Explanation: A single-beam spectrophotometer uses a single light

beam to pass through the sample. The intensity of the light is
measured before and after passing through the sample, and this
difference is used to calculate absorbance.
5. Which instrument measures the concentration of atoms using a
flame?
o Answer: B) Atomic absorption spectrophotometer

o Explanation: The atomic absorption spectrophotometer (AAS)

measures the concentration of specific atoms by passing light through
a sample that has been atomized in a flame. The amount of light
absorbed by the atoms is directly related to their concentration.
6. In atomic absorption spectrophotometry, the light absorbed is
directly proportional to:
o Answer: A) The atomic concentration in the sample

o Explanation: In AAS, the amount of light absorbed by free atoms in

the gaseous state is proportional to their concentration. As the number
of atoms in the flame increases, more light is absorbed.
7. Which type of photometric instrument involves the emission of
photons during chemical reactions?
o Answer: A) Chemiluminescence

o Explanation: Chemiluminescence involves the emission of light

(photons) from a chemical reaction. It is different from fluorescence
because no external light source is required to excite the molecules.
8. What is the primary application of flame photometry?
o Answer: A) Determining ion concentration

o Explanation: Flame photometry is primarily used to measure the

concentration of alkali and alkaline earth metals, such as sodium and
potassium. The ions in the sample emit light when excited by the
flame, and the intensity of this light is measured.
9. Which method measures light scatter due to suspended particles?
o Answer: C) Nephelometry

o Explanation: Nephelometry measures the amount of light scattered

by suspended particles in a sample. It is used to assess the
concentration of particulates in a solution, especially for turbid or
cloudy samples.
10.Ion-selective electrodes are designed to be sensitive to:
o Answer: B) Specific ions

o Explanation: Ion-selective electrodes (ISEs) are designed to

selectively measure the concentration of specific ions, such as H⁺ for
pH measurements or K⁺ for potassium. These electrodes are used in
 electrochemical analyses and are highly sensitive to particular ions in
solution.

These explanations should help clarify how these principles and instruments work in
the context of clinical chemistry and spectrophotometry.
4o
You said:
do it from the rest 11-50
ChatGPT said:
ChatGPT
Here are explanations for the rest of the answers (11-50) based on the same topics:

11.Which law explains the relationship between absorbance and

concentration in a spectrophotometer?
 Answer: B) Beer’s Law
 Explanation: Beer’s Law describes how absorbance is directly proportional
to the concentration of an absorbing substance in solution. It's fundamental
to spectrophotometric analysis.
12.What factor affects the wavelength accuracy in a
spectrophotometer?
 Answer: D) Monochromator
 Explanation: The monochromator in a spectrophotometer isolates a specific
wavelength of light. Its accuracy directly affects the precision of wavelength
selection.
13.What is the purpose of a cuvette in spectrophotometry?
 Answer: B) Hold the sample
 Explanation: The cuvette is a small container that holds the sample solution
for light to pass through in spectrophotometry.
14.Which component of a spectrophotometer converts light into an
electrical signal?
 Answer: C) Detector
 Explanation: The detector (such as a photodiode or photomultiplier tube)
converts the transmitted or absorbed light into an electrical signal that can
be measured.
15.Which type of spectrophotometer uses a beam splitter to
simultaneously measure the sample and reference?
 Answer: A) Dual-beam
 Explanation: A dual-beam spectrophotometer splits the light into two beams
—one passes through the sample, and the other through the reference. This
design enhances accuracy by compensating for fluctuations in light intensity.
16.What is the principle of atomic absorption spectrophotometry?
 Answer: B) Absorption of light by free atoms
 Explanation: In atomic absorption spectrophotometry, free atoms absorb
light at specific wavelengths, and this absorbance is proportional to the
concentration of those atoms in the sample.
17.In fluorometry, what happens when a molecule absorbs light?
 Answer: D) It emits light at a different wavelength
 Explanation: Fluorometry is based on fluorescence, where molecules absorb
light at one wavelength and emit it at a longer wavelength. This principle is
used to detect low concentrations of analytes.
18.What is the role of a monochromator in spectrophotometry?
 Answer: A) To isolate a specific wavelength
 Explanation: The monochromator selects and isolates the desired
wavelength of light from a broad spectrum, ensuring that only light of that
wavelength reaches the sample.
19.Which of the following is not a part of a flame photometer?
 Answer: C) Mass analyzer
 Explanation: A mass analyzer is used in mass spectrometry, not flame
photometry. Flame photometers primarily consist of a flame, atomizer, and
light detector.
20.Which type of energy is responsible for excitation in fluorometry?
 Answer: C) Light energy
 Explanation: Fluorometry involves the excitation of molecules by light
energy, which causes them to emit light at a different wavelength.
21.What does the term “chemiluminescence” mean?
 Answer: A) Light emission from a chemical reaction
 Explanation: Chemiluminescence refers to the emission of light as a result
of a chemical reaction, commonly used in analytical techniques such as
immunoassays.
22.Which of the following best describes nephelometry?
 Answer: D) Measurement of scattered light
 Explanation: Nephelometry measures the intensity of scattered light by
suspended particles in a solution, commonly used to assess turbidity.
23.Which of the following instruments is used to measure light
scattered by particles?
 Answer: C) Nephelometer
 Explanation: A nephelometer measures the amount of light scattered by
particles suspended in a solution. It’s commonly used in clinical and
environmental testing.
24.What kind of chemical reaction produces light without requiring
external radiation?
 Answer: A) Chemiluminescence
 Explanation: In chemiluminescence, the chemical reaction itself produces
light, so no external light source (excitation radiation) is needed.
25.Which method is used to measure specific ion concentrations in
solutions?
 Answer: C) Ion-selective electrode
 Explanation: Ion-selective electrodes (ISEs) are designed to measure the
concentration of specific ions in a solution, such as H⁺ for pH measurement or
Na⁺ for sodium.
26.Which electrode type is sensitive to hydrogen ions (H+)?
 Answer: A) pH electrode
 Explanation: A pH electrode is an ion-selective electrode sensitive to
hydrogen ions, making it a critical tool for measuring pH in solutions.
27.Which component of an ion-selective electrode serves as a stable
reference point?
 Answer: B) Reference electrode
 Explanation: The reference electrode provides a stable, known potential
against which the potential of the ion-selective electrode is measured.
28.What does the Nernst equation describe?
 Answer: D) The potential difference based on ion concentration
 Explanation: The Nernst equation relates the potential difference of an
electrochemical cell to the concentration of ions, fundamental for ion-
selective electrode function.
29.In chromatography, the mobile phase refers to:
 Answer: A) The phase that moves through the column
 Explanation: The mobile phase in chromatography is the liquid or gas that
moves through the column, carrying the analytes to be separated.
30.What is the stationary phase in chromatography?
 Answer: C) The phase that does not move
 Explanation: The stationary phase remains fixed inside the column. The
interaction between the stationary phase and the analytes determines their
separation.
31.Which chromatography method separates substances based on their
adsorption?
 Answer: A) Adsorption chromatography
 Explanation: Adsorption chromatography separates substances based on
their differing tendencies to adsorb onto the stationary phase.
32.Which type of chromatography is based on the charge of analytes?
 Answer: C) Ion-exchange chromatography
 Explanation: In ion-exchange chromatography, substances are separated
based on their charge, which determines how strongly they interact with the
stationary phase.
33.What does HPLC stand for?
 Answer: B) High-Performance Liquid Chromatography
 Explanation: HPLC is a type of liquid chromatography used to separate,
identify, and quantify components in a mixture with high resolution and
sensitivity.
34.Which is not a component of an HPLC system?
 Answer: D) Flame
 Explanation: A flame is not used in HPLC. The system typically includes a
pump, column, detector, and sample injector.
35.Gas chromatography is used to analyze:
 Answer: B) Volatile compounds
 Explanation: Gas chromatography (GC) is designed to separate and analyze
compounds that are volatile or can be vaporized.
36.In mass spectrometry, what is the purpose of the mass analyzer?
 Answer: A) To separate ions based on their mass-to-charge ratio
  Explanation: The mass analyzer in mass spectrometry separates ions
according to their mass-to-charge ratio (m/z), allowing identification of
different substances.
37.What is MALDI-TOF used for?
 Answer: C) Analyzing proteins and large biomolecules
 Explanation: MALDI-TOF (Matrix-Assisted Laser Desorption/Ionization Time of
Flight) is a mass spectrometry technique used to analyze large biomolecules,
such as proteins and peptides.
38.Which technique separates molecules based on both molecular
weight and structure?
 Answer: B) Mass spectrometry
 Explanation: Mass spectrometry separates molecules based on their
molecular weight and structure, providing detailed identification of
compounds.
39.What is the mobile phase in gas chromatography?
 Answer: B) Gas
 Explanation: The mobile phase in gas chromatography is a carrier gas,
typically helium or nitrogen, which moves the analytes through the column.
40.Which technique is commonly used for detecting metal
concentrations in environmental samples?
 Answer: A) Atomic absorption spectrophotometry
 Explanation: Atomic absorption spectrophotometry is widely used to detect
trace metals in environmental samples like water or soil.

Finals
Electrolytes
Most abundant cat ion is sodium
3rd si calcium
4th si magnesium

Polydipsia
Water deficit
Hyperosmolality is a condition where electrolytes, glucose, and urea in the blood is
abnormally high.
Caused by dehydration
Hypernatremia is a condition where an abnormally high concentration of sodium in
the blood. Excessive sodium intake
Hyponatremia – typically is under 125 mmol/L
Treatement of hyponatremia is – AVP receptor

Hypernatremia – serum levels is 160 mmol/L

Serum plasma ref range is 135-145 mmol/L
Hyperkalemia renal insufficiency