Agilent Technologies gc/ms series User Manual

70
Order online at www
.agilent.com/chem/store
Cool On-Column Inlet Practices and Rationales
Parameter Selection/Setting Rationale
Initial inlet temperature Equal to or 3°C above column
oven temperture
Ensures sample focusing in
solvent front
Initial inlet temperature ramp Same as oven (oven track)
Faster than oven
Simple and effective
Narrows initial peak width
Injection volume 0.1 - 2.0 µL liquid Use smaller injections for small
ID columns
Depends on column capacity
Injection technique Automatically slower injection
Fused silica needle
Projects droplets away from
syringe tip
Use for manual injection into
small ID columns
Oven temperature Inlet temperature or slightly
lower
Prevents backflash
Column flow 50 - 80 cm/sec
30 - 50 cm/sec
Use for H
2
carrier gas
Use for He carrier gas
Septum purge 12 - 15 mL/min Use if installed to prevent
ghosting
Quantification All methods Inherently reproducible technique
Lack of discrimination
Retention gap requirements 1 - 3 m, deactivated
530 µm
Corrects peak distortion
Protects column from non-
volatile components
Permits autoinjection with
narrow-bore columns
There are some limitations to
cool on-column inlets, including
the following:
• Maximum sample volumes
are smaller compared with other
inlets (0.5 µL to 2.0 µL).
• Solute peaks eluting just before
the solvent cannot be focused
and are difficult to determine.
• Capilliary columns (especially those
with a large phase ratio or small
inner diameter) can be easily
overloaded with sample.
• Parameters such as initial column
temperature, solvent nature,
and injection rate must often
be optimized.
Tips & T
ools

Agilent Technologies gc/ms series Specifications

General

Dynamic Range	10^6
Mass Range	1050 amu
Mass Resolution	Unit mass resolution
Scan Speed	Up to 12, 500 amu/sec
Ionization Mode	Electron Ionization (EI), Chemical Ionization (CI)
Temperature Range	Up to 350°C
Vacuum System	Turbomolecular Pump
Data System	Agilent MassHunter

Summary

Gas Management

Gas Purity and Selection

Gas Purification Systems

Overview of purifiers for removing oxygen, moisture, and hydrocarbons to achieve proper gas purity.

Sample Introduction

Selecting Vial Septa Materials

Gold Standard Autosampler Syringes

Syringe Troubleshooting Guide

Guidance on common syringe problems like bent plungers or needles and their solutions.

Inlets

Premium Non-Stick Septa

Split/Splitless Liners

Agilent MS Certified Liners

Split/Splitless Inlets

Overview of the popular split/splitless inlet and troubleshooting common issues like peak broadening.

Cool On-Column Inlets

Advantages of cool on-column injection, sample considerations, and troubleshooting tips.

Purged Packed Inlets

Programmed Temperature Vaporizer (PTV) Inlets

Benefits, practices, and rationales for PTV inlets, offering flexibility in sample introduction.

Detectors

Flame Ionization Detector (FID)

Routine maintenance, typical problems, and troubleshooting for the FID.

Electron Capture Detector (ECD)

Liner selection, makeup gas adapter maintenance, thermal cleaning, and leak testing for ECD.

Thermal Conductivity Detector (TCD)

Filament maintenance, lifetime extension, cell contamination, and solvent flush procedures for TCD.

Flame Photometric Detector (FPD)

Recommended gas flows, maintenance, contamination, and ignition problems for the FPD.

Nitrogen Phosphorus Detector (NPD)

GC/MS Systems

Maintaining Mass Selective Detectors (MSD)

Benefits of maintaining GC/MSD systems, including reduced downtime and longer lifespan.

MSD Contamination

Identifying contamination sources in the GC and MSD, and common contaminants and their origins.

Mass Spectrometer Symptoms

Ion Source

Installing a Capillary Column in the GC/MSD Interface

Vacuum Systems and Pumps