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Flashcards in instrumentation Deck (34)
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1

mass spectrometer

used to analyse blood of race horses for drugs, identify substances

2

Atomic Absorption Spectroscopy (AAS)

used to analyse water samples for heavy metals (Cd, Hg, Pb)

3

GC

used with MS in drug testing also blood alcohol levels

4

HPLC

used to separate less volatile mixtures eg. growth promoters in meat

5

IR spec

used to identify functional groups + identify drugs

6

UV spec

quantitative used to find amount of organic substances
eg. drugs

7

instruments

gas chromatograph
mass spectrometer
atomic absorption spectrometer
high-performance liquid chromatograph
infrared spectrometer
ultraviolet absorption spectrometer

8

Gas Chromatograph - principles

different components of a mixture have diff interactions w/ the stationary + mobile phases

9

Gas Chromatograph - processes

-injection
-transport of sample along column
-separation in column
-detection

10

Mass Spectrometer - principles

positively charged ions are separated on basis of their relative masses in a magnetic field

11

Mass Spectrometer - processes

-vaporisation
-ionisation
-acceleration
-separation
-detection

12

Atomic Absorption Spectrometer - principles

ground state atoms of an element absorb light characteristic of that element. Absorbance is directly proportional to concentration

13

Atomic Absorption Spectrometer - processes

-Sample soln sprayed into a flame + sample element converted into atoms of that element
-Ground state atoms absorb radiation from source made from element
-Absorbance measured

14

High-performance liquid chromatograph - principles

Different components of mixture have different tendencies to absorb onto v. fine particles of a solid in the HPLC column

15

High-performance liquid chromatograph - processes

-injection
-transport of sample along column
-separation in column
-detection

16

infrared spectrometer - principles

-Molecules of a substance absorb infrared light of different frequencies.
-The combination of frequencies absorbed is peculiar to the molecules of that substance

17

infrared spectrometer - processes

-IR radiation passes thru sample
-sample absorbs IR radiation at specific wavelengths which are detected
-absorption spectrum is obtained

18

ultraviolet absorption spectrometer - principles

-Absorption of UV radiation by molecules results in the promotion of electrons from their ground state energy levels to higher energy states
-Absorbance is directly proportional to concentration

19

ultraviolet absorption spectrometer - processes

-UV light passed through sample and a blank
-absorption spectrum is obtained

20

use of thin-layer chromatography in forensic science

the separation of dyes taken from fibres

21

procedure: separate components in a mixture of indicators using paper chromatography

-add solvent to bottom of tank. Cover, allow to stand for a few hours - become saturated w/ solvent vapour

-draw line near top of rectangular sheet of chrom. paper and just above eluent

-place small spot of each indicator + mixtures at diff points on line near bottom of paper using capillary tube. Allow to dry

-place in tank, ensuring solvent level is below line spots of indicators

-run the chromatogram until solvent reaches line near top of paper

(diagram in sheet)

22

procedure: separate components in a mixture of indicators using thin-layer chromatography

-using capillary tube, place small spot of each sample near bottom of plate just above eluent. Allow to dry.

-stand plate in tank with eluent, ensuring samples are above the surface of the liquid

-Cover tank, allow solvent front to rise up to plate near top.

(diagram in sheet)

23

How to purify impure copper by electrolysis

-incl diagram

-battery used as power supply
-copper sulfate electrolyte
-impure copper acts as anode, is oxidised
-pure copper acts as cathode
-copper ions (Cu²⁺) in soln reduced, pure copper plates out on cathode

24

Copper electrolysis - equation for reactions that take place at electrodes

Cu²⁺ + 2e⁻ --> Cu

Cu --> Cu²⁺ + 2e⁻

25

what happens to impurities in the copper during electrolysis?

fall to bottom of container / found under anode / anode mud (sludge)

26

Technique vs Equipment

Spectroscopy is the technique

Spectrometer in the equipment

27

chromatography - why different components of the mixture travel diff distances along paper

explain using principle

28

mass spectrometry application

-measuring relative atomic mass
-identifying species
-water analysis
-quality control
-environmental analysis
-separating isotopes

29

gas chromatography application

-blood alcohol analysis
-drug testing
-separating water pollutants
-determining position of double bond in molecule

30

What HPLC stands for

High-performance liquid chromatography