844 Series Combustion | Carbon and Sulfur Analysis by Combustion | LECO

844 Series Combustion
Carbon and Sulfur Analysis by Combustion

Easily analyze your wide-range carbon and sulfur content with our CS844 for the determination of carbon and sulfur in primary steels, ores, finished metals, ceramics, and other inorganic materials using the combustion technique. State-of-the-art hardware and our exclusive Cornerstone® touch-screen software platform provide your laboratory with increased usability and a lower cost-per-analysis.

  • Maximize laboratory productivity with automation
    • 10- and 60-position shuttle loaders or integrated robotic process loaders available.
    • High-efficiency autocleaner/vacuum system keeps maintenance to a minimum
    • Automatic combustion tube service and exchange system
  • Ergonomic, operator-centered design with a boom-mounted touch-screen interface
  • Improved IR cell design provides dual-range detection and improved lifetime and stability
  • High-efficiency furnace with low-maintenance design reduces the need for additional accelerant and cleaning


The 844 series is ideal for the following applications: primary steels, ores, finished metals, ceramics, alloys, and other inorganic materials.

The CS844 Carbon/Sulfur system is designed for wide-range measurement of carbon and sulfur content of metals, ores, ceramics, and other inorganic materials. The instrument features custom software designed specifically for touch operation.

A pre-weighed sample of approximately 1 gram is combusted in a stream of purified oxygen using RF induction to heat the sample. Carbon and sulfur present in the sample are oxidized to carbon dioxide (CO2) and sulfur dioxide (SO2), and swept by the oxygen carrier through a heated dust filter, a drying reagent, and then through two non-dispersive infrared (NDIR) cells, where sulfur is detected as SO2. The gas flow continues past a heated catalyst, where carbon monoxide (CO) is converted to CO2 and where SO2 is converted to sulfur trioxide (SO3), which is subsequently removed by a filter. Carbon is then detected as CO2 by a second pair of NDIR cells. A pressure controller is used to maintain constant pressure in the NDIR cells so as to reduce interference from natural variations in atmospheric pressure. The final component in the flow stream is an electronic flow sensor, which is used for diagnostic purposes to monitor the carrier flow.

Non-dispersive infrared cells are based on the principle that CO2 and SO2 absorb infrared (IR) energy at unique wavelengths within the IR spectrum. Incident IR energy at these wavelengths is absorbed as the gases pass through IR absorption cells. Since absorption is dependent upon the path length, short and long path-length IR cells are provided for measurement of high and low range signals. The software automatically selects which cell to use for optimum measurement. The concentration of unknown samples is determined relative to calibration standards. To reduce interferences from instrument drift, reference measurements of pure carrier gas are made prior to each analysis.



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844 Series Details

Carbon and Sulfur Analysis by Combustion with the CS844

  • Models
    1. CS844 Carbon/Sulfur

    1. C844 Carbon

    1. S844 Sulfur

    1. CS844ES Enhanced Sulfur, Carbon
    1. S844ES Enhanced Sulfur

928 Series Macro Determinator | Carbon/Nitrogen/Sulfur, and Nitrogen/Protein Analysis by Combustion | LECO

928 Series Macro Determinator
Carbon/Nitrogen/Sulfur, and Nitrogen/Protein Analysis by Combustion

Easily handle heterogeneous, difficult to prepare, or low analyte level samples with the 928 Series Macro Determinator for determining Carbon/Nitrogen/Sulfur and Nitrogen/Protein by Combustion. State-of-the-art hardware and our exclusive Cornerstone® touch-screen software platform provide your laboratory with an increase in throughput, uptime, and reliability. Macro sample mass ability (up to 3 grams for Nitrogen/Protein model regardless of sample carbon content) with rapid cycle times and a low cost-per-analysis make the 928 Series ideal for these challenging macro samples.

  • Maximize laboratory productivity with unmatched sample throughput
    • Rapid cycle time of 5 minutes
    • Sample mass: Up to 3.0 g for nitrogen (FP) (1.0 g nominal); up to 1.0 g for carbon/nitrogen (0.5 g nominal); up to 0.3 g for carbon/nitrogen/sulfur (0.2 g nominal)
    • Optional 100-sample position autoloader for sequential and non-sequential analysis
  • Ergonomic, operator-centered design with boom-mounted touch-screen interface
  • Easy access to all reagent tubes and common maintenance areas for simplified maintenance
  • Extended reagent lifetimes contribute to a low cost-per-analysis
  • Horizontal furnace design with maximum temperatures up to 1450oC ensure complete oxidation of samples
  • Expanded furnace efficiency and reliability with a regent-free design


The 928 series is ideal for the following applications: Meats, Feeds, Forage, Pet Foods, Grains, Milled Products, Starch, Fermentation Products, Dairy and Cheese Products, Soils, Sediments, Fertilizers, Plant Tissue, Filtration Media, Waste Materials, Fiber and Textiles, Resins and Polymers, Paper Products, and Petroleum Products and Additives

The 928 series determines nitrogen/protein, carbon/nitrogen, or carbon/nitrogen/sulfur in a multitude of organic matrices from foods and feeds, to soils and fertilizers. The system utilizes a high temperature horizontal ceramic combustion furnace designed to handle macro sample mass with a rapid analysis time delivering unsurpassed application capabilities and throughput.

To start an analysis, a macro-sized sample is weighed into a ceramic boat and placed in the 100-position loader. A fully automated analysis sequence transfers the sample to a sealed purge chamber, where entrained atmospheric gas is removed. The purged sample is transferred automatically to the furnace, which can be operated at temperatures from 1100 °C to 1450 °C. To ensure complete and rapid combustion (oxidation) of the sample, the furnace environment is composed of pure oxygen with a secondary oxygen flow directed to the sample via a ceramic lance. The combustion gases are swept from the furnace through a thermoelectric cooler (nitrogen/protein and carbon/nitrogen models), or an anhydrone reagent (carbon/nitrogen/sulfur model), to remove moisture, and collected in a thermostatically controlled ballast volume. The gases equilibrate and mix in the ballast before a representative aliquot of the gas is extracted and introduced into a flowing stream of inert gas for analysis. Depending upon the analyzer model, the aliquot gas is carried to a non-dispersive infrared (NDIR) cell for the detection of carbon (as carbon dioxide) and sulfur (as sulfur dioxide), and a thermal conductivity cell (TC) to detect nitrogen (N2). Unlike NDIR cells, TC cells are chemically non-specific, so a series of reagents and scrubbers are used to ensure quantitative detection of N2 without chemical interference. A heated reduction tube, filled with copper, is used to convert nitrogen oxide species (NOx) to N2 and to remove excess oxygen. Carbon dioxide (CO2) is removed by LECOSORB and water (H2O) is removed by Anhydrone.

Careful sequencing of the analysis by the Cornerstone® brand software provides maximum sample throughput by interleaving the sample loading sequence with quantitation of the aliquot gases from the previous sample. As soon as the combustion gas is collected in the ballast, and the analysis sequence is initiated for the next sample.

The determined composition of the sample is displayed by Cornerstone in weight percent or parts-per-million but can be displayed in other custom units if preferred.

Many diagnostic sensing capabilities are included in the 928 Series analyzer. Multiple Pressure Transducers (PT) to ensure the presence of sufficient oxygen and helium, and provide the ability to leak check individual segments of the flow path. Digital Mass Flow Controllers (MFC's) are used to control and measure critical flows of oxygen and helium. Thermal sensors and heaters are used to thermostatically control the temperature of critical components such as the furnace, the ballast, the dose loop, the helium MFC, the NDIR cell, and the TC cell.

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928 Series Details

Carbon/Nitrogen/Sulfur and Nitrogen/Protein Analysis by Combustion with the 928 Series Macro Determinator

  • Models
    1. FP928 Nitrogen/Protein

    1. CN928 Carbon/Nitrogen

    1. CNS928 Carbon/Nitrogen/Sulfur