Mass Spec

Question 1

what is Mass Spec?

Answer 1

Analytical method to measure molecular or atomic weight

Question 2

components

Answer 2

1) Ion source : charge atom/ molecule = Gas
2) Mass analyzer : separates ions with diff m/z
3) Detector : see ions

Question 3

Units

Answer 3

Daltons
1 Da=1g/ mol

Question 4

% mass accuracy

Answer 4

measured - True / True x 100

Question 5

PPM accuracy

Answer 5

Measured - True /True x 10 ^ 6

Question 6

Sensitivity expression units

Answer 6

Molar fraction ( pmol) or grams (mg) per volume fraction
Lower= Better

Question 7

Signal to noise ratio

Answer 7

compares levels of desired signal to background noise

Question 8

LOD + LOQ

Answer 8

Limit of Detection + Limit of Quantification

Question 9

Resolving Power

Answer 9

mass/ (Delta) Mass (peak width necessary for Separation

Question 10

ESI principles

Answer 10

Molecules to Gas using high voltage power supply to charge liquid
Jet expelled + droplets repel = mist
Droplets evapourate leaving analyte

Question 11

LC-MS

Answer 11

physical Separation Of HPLC with mass analysis

Question 12

ESI benefits

Answer 12

very sensitive , Positive+ negative mode

Question 13

MALDI-TOF on?

Answer 13

High molecular mass + thermoliable , non- volatile compounds

Question 14

MALDI - TOE Benefits

Answer 14

Easy to use, tolerant to buffers

Question 15

Matrix of MALDI-TOF

Answer 15

must have conjugated Structure to absorb light
Protects analye + facilitates charge transfer

Question 16

TOF analyzer

Answer 16

Uses Reflectron (Reflect ions back)
Longer tube = Better resolution
smaller m /z = quicker
Same charge= Bigger mass first vice versa

Question 17

Quadrupole Mass Filter

Answer 17

stable ions pass through to detector
unstable removed

Question 18

Tandem Mass Spec

Answer 18

Multiple analyzers generate structural info
E -g 1= Select ion, 2= fragments ion, 3= Analysis of fragments

Question 19

collision induced Dissociation

Answer 19

ion collides with collision gas = fragmentation

Question 20

Product ion scan

Answer 20

lon focussed, collisions, scanning of products

Question 21

precursor ion scan

Answer 21

Scans precursor on

Question 22

BMS applications X3

Answer 22

structures of biomolecules, How drugs are used in body, Forensic analysis

Question 23

protein ID Top down

Answer 23

Direct protein sequencing= whole protein

Question 24

Protein ID Bottom up

Answer 24

Protein cut by Trypsin at certain amino acids = Peptide

Question 25

Peptide Bond

Answer 25

Carboxyl group reacts with amino group= Release water

Question 26

b ions (left)

Answer 26

mass of amino and +1 ( Sum of N-term )

Question 27

y ions (right)

Answer 27

mass of amino acids +19 (sum of OH group )

Question 28

Multidimensional L C-MS

Answer 28

HPLC+ MS (fractionate + analyze all )

Question 29

Mass fingerprint method

Answer 29

2D electrophoresis, cut out, Trypsin digestion, extract, Mass spec, Data search