Determining if the EI inner source contamination levels are high on the AutoSpec - WKB95001

OBJECTIVE or GOAL

Determining whether the AutoSpec EI inner source is contaminated (and possible sources) by looking for common background ion intensities.

ENVIRONMENT

• AutoSpec Premier (P)
• AutoSpec Ultima (M)

PROCEDURE

Set the following instrument conditions and leave in Operate mode for one hour so contaminant ion intensity can stabilize.

• Source Temperature = 280 °C
• Electron Energy = 70eV
• Trap Current = 200uA
• Resolution = 1000
• Detector Voltage = 300V (@2E4 gain)
• Santovac (diffusion pump oil) ions 446Da and 77Da <0.02V and <0.2V respectively
• Rotary pump ion 57Da <1.0V
• Phthalates (plastics, gloves, sample vials, and so on) 149 and 167Da <0.2V and <0.5V respectively
• Siloxanes (column bleed, sample vial seals) 207 and 281 both <0.1V

ADDITIONAL INFORMATION

A lot of contaminants condense on the EI filament when in standby then vaporize when the instrument is switched into operate. The one hour stabilization period is extremely important to give reliable results.