Wednesday, 02 December 2020 15:43

ChromaTOF® | Identification Grading System | LECO

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ChromaTOF® IGS | Identification Grading System | LECO

ChromaTOF® Identification Grading System


Bring the Power of Accurate Mass and Confidence to your Identification Problems

LECO's Identification Grading System (IGS) eases data review by allowing users to quickly see, justify, have confidence in, and report on which chemicals are in a particular sample. This in turn allows a user to make confident decisions on what to do next.

Start Knowing What is in Your Sample

The IGS uses all the available chemical information generated from the Pegasus® GC-HRT+ 4D to add confidence to your unknown unknown identification process.

The IGS gives a grade to a particular identification based on 4 criteria:

  1. Presence and accurate mass of a molecular ion
  2. Presence and good correlation of a spectral similarity score from a curated library
  3. Accurate masses of sensible potential formulae of fragmented ions corresponding to a spectral library hit
  4. Matching retention index from the library hit

The higher the value of the grade, the more confident you can be in your identification.

The true power of identification can only be realized with the combined power of GCxGC and high resolution time-of-flight mass spectrometry (TOFMS).

  • GCxGC separates coeluting species and gives cleaner mass spectra than other techniques.
  • TOFMS enables unskewed mass spectra across a chromatographic peak even across very narrow second dimensional peak; which, when combined with deconvolution, yields the highest quality spectra that you can generate.

Born out of the United States of America Environmental Protection Agency (EPA)’s Non-Targeted Analysis Collaborative Trial (ENTACT), the IGS is LECO’s solution to the time-intensive process of data review.

Take for example the unfiltered deconvolution results from a GCxGC-TOFMS analysis of a sample from the EPA's ENTACT project (below, left). By applying the IGS filter, we can quickly view only the most confident indentifications. This simplification is dramatic and enables you to immediately begin investigating the "unknown unknowns," as indicated by the arrows in the diagram image on the right.

ChromaTOF IGS Sample Example

Left: Initial HRD (n=4800). Right: IGS > 2 (n=245)

Of the known compounds entered into the sample from this particular example (which was provided to LECO as a blind sample), IGS identified approximately 80% of the known peaks. The combination of GCxGC and high resolution TOF was proven to be necessary for this confidence. Read "Identifying Small Molecules via High Resolution Mass Spectrometry" for more information.

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Monday, 26 October 2020 15:43

TF Series Tube Furnaces

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TF Series Laboratory Technician Insert Crucible into Tube Furnace

TF Series Tube Furnaces

The LECO Cornerstone® TF Tube Furnaces are versatile, energy-efficient resistance furnaces designed for baking crucibles to reduce contaminants that would interfere with analytical results.

  • Long-life molybdenum disilicide heating elements have an operating temperature range of 800 °C to 1350 °C
  • Integrated digital furnace controller displays set point or actual temperatureand provides overtemperature protection
  • TF4 Quad Tube Furnace system has six heating elements
    • Allows operator to burn off crucibles in four combustion tubes for demanding, high-volume installations supplying two to four units
  • TF2 Dual Tube Design has four heating elements
    • Efficiently supplies lower volume installations of one to two systems

The table below illustrates the impact of preheating 528-018 Crucibles on carbon and sulfur results of a high purity iron reference material certified at 5 ppm carbon and 2 ppm sulfur (1250 °C for 15 min).

tf crucible blank furnace comparisons

The new furnace design and increased crucible capacity use 60% less energy than the previous models for significant savings inoperating costs. The chart below exhibits the differences in operating costs while operating the various systems at 1350 °C, considering continuous operation with a full load of crucibles.
 
tf tube furnace efficiency comparison
 

 

 

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TF Series Details

Carbon and Sulfur Analysis by Combustion with the CS844

  • Models
    1. TF4 Quad Tube Furnace

    1. TF2 Dual Tube Furnace