Chapter 5 - Ionization methods in LC-MS - part 2

Question 1

ESI is affected by 4 main variables

Answer 1

Capillary voltage
Eluate flow rate
Liquid surface tension
Electrolyte concentration

Question 2

Standard electrospray capillaries are constructed from

Answer 2

stainless steel.

Question 3

The practical upper limit to eluate flow in pure electrospray is

Answer 3

10-20 microliters.

Question 4

The core of the electrosprayed aerosol contains ________ diameter droplets than in the extremities of the spray.

Answer 4

larger

Question 5

Efficiency of ion production will be higher at the ________ of the aerosol.

Answer 5

perimeter

Question 6

Cluster ions are formed by

Answer 6

polar molecules in the gas phase attaching to the analyte ions.

Question 7

Gas used to help prevent cluster ions.

Answer 7

N2

Question 8

Dielectric capillaries are used to

Answer 8

prevent cluster ions.

Question 9

How to reduce the need to clean transfer tube and orifice.

Answer 9

Use curtain gas, off axis spray, and/or orthogonal spray.