Trace Moisture Analysis System

New Approach Using Gas Chromatography with the Novel BID

Unlike traditional wet chemistry methods, this new method uses Gas Chromatography (GC) with a newer detector - the Barrier Discharge Ionization Detector (BID). The BID is a highly sensitive device that creates ionization from a Helium-based, dielectric barrier discharge plasma. A 17.7eV plasma is generated by applying a high voltage to a quartz dielectric chamber, in the presence of helium at a relatively low temperature. Compounds that elute from the GC column are ionized by this He plasma energy and then detected by the collection electrode and processed as peaks.

The BID is more sensitive than both a Thermal Conductivity Detector (TCD) and a Flame Ionization Detector (FID) with the ability to analyze down to sub-ppm levels of water. Additionally, the method uses MilliporeSigma's new, highly polar ionic liquid column, Watercol™, which provides excellent water retention, separation, and peak shapes.

Because wet chemistry techniques are prone to interfering compounds, such as mercaptans and sulfides, this method uses a column separation technique to separate these and other compounds in the sample. Anyone with GC experience can quickly set up and run this method. Those without GC experience are easily trained by the Shimadzu Scientific Instruments service and tech support team.

Moisture Analysis by GC/BID offers the following advantages:

1. Easily analyzes both liquid and gas samples
2. Uses a variety of Watercol™ GC columns depending on your matrices
3. Uses a simple, high sensitivity, and very stable low-cost GC detector

The Barrier Discharge Ionization Detector (BID)

The BID achieves over 200 X's higher sensitivity for organic compounds over a TCD. In addition, conventional analytical techniques require a GC system configuration with multiple detection schemes to analyze for permanent gases and light hydrocarbons. The use of a methanizer and FID is often required to detect ppm levels of CO and CO₂. However, the BID replaces all of this hardware and allows for the highly sensitive detection of mixtures of inorganic gases and light hydrocarbons.

New ASTM Work Item - Precursor to an ASTM Standard Method

A new test method work item (WK59649): A New Standard Test Method for the Determination of Water in Liquefied Petroleum Gas (LPG) using Gas Chromatography and Barrier Discharge Ionization Detection (BID) has been submitted by the ASTM D02 H00 committee. This method uses the new GC/BID/Liquid/gas sampling valve with the Watercol™ (MilliporeSigma*) GC column. Be on the lookout for the official method once it is approved by ASTM.

Moisture Analysis in Many Types of Petroleum Samples

  (Lillian A. Frink; Daniel W. Armstrong, 8194-8201; Anal. Chem. 2016, 88)

a - Standard addition with Aerosol-OT dissolved in moisture
b - Standard addition is not feasible due to the samples high viscosity, complexity of samples, and immiscibility with the added moisture standard
c - Moisture measured in a 0.5g sample utilizing headspace gas chromatography

Many different types of samples can benefit from analyzing moisture content via the GC/BID Watercol™. Excellent precision and accuracy are achieved using manual or automated systems. Depending on the types of samples, a liquid/gas sampling valve can be used to introduce the samples to the GC or the Shimadzu HS-20 NX Headspace Sampler.

* MilliporeSigma, the life science business of Merck KGaA
   Watercol is a trademark of MilliporeSigma.