Docstoc

Total Sulfur Determination in White Oils and Related Materials

Document Sample
Total Sulfur Determination in White Oils and Related Materials Powered By Docstoc
					                                                             06/00

                                                             EA_S3000_08_00_e


Total Sulfur Determination in White Oils and
Related Materials

multi EA 3000 S

1. Introduction

The accurate and rapid determination of total Sulfur content in food grade White Oils
and related materials is important to pharmacueticals, food, refineries, processing
plants, storage facilities, and end users. Sulfur compounds present in these materials
are generally undesirable and must be controlled for regulatory reasons.


2. Principle of Operation
                                    1000°C
Combustion:         R – S + O2                    CO2 + H2O + SO2 + oxides
                                    electrolyte
Detection:          SO2 + 2H2O                    H2SO4 + 2H+ + 2e-

Sample combustion occurs in a relatively pure oxygen atmosphere at a temperature
              C.
above 1000° All sulfur is quantitatively converted to sulfur dioxide. The sulfur
dioxide is reacted with the sensing electrode in a 3-electrode electrochemical cell.
This reaction produces a measurable current which is directly proportional to the
amount of sulfur in the original sample material.


3. Analytical Parameters

Furnace Temperature:             1050°C
Converter Temperature:           300°C
Gas Flows:
            Inlet Argon          150 mL / min
            Inlet Oxygen         50 mL / min
            Main Oxygen          200 mL / min
Sample Size:                     10 µL
Injection Rate:                  1 µL / sec




                                                                                 1/2
                                                                                   06/00

                                                                                   EA_S3000_08_00_e


4. Analytical Options

This method of analysis will yield an estimation of the Total Sulfur content of the
White Oil samples. Also, an estimation of Total Nitrogen content may be derived from
the same sample injection by the addition of a Nitrogen Detector.


5. Calibration

Traceable Sulfur calibration standards were purchased having known concentrations
to approximate the expected analytical range of analysis. For example, 0, 0.5, and 1
ppm Sulfur standards of Dibenzothiophene in Toluene, can be analyzed to provide a
multi-point calibration curve. Triplicate injections of each volume was made at 1
µL/sec. The curve was saved to memory for comparison with subsequent sample
analyses.


6. Analytical Data

Sample                             S Concentration(ppm)                         SD                       RSD
White Oil #1                              0.083                                0.013                     15.6
White Oil #2                              0.150                                0.011                      7.3
White Oil #3                              0.489                                0.081                      1.7


7. Instrumentation Used

Item                                                        Description
multi EA® 3000 S                                            Electrochemical Sulfur Analyzer complete
                                                            with Furnace, SO2 Detector, Elemental
                                                            Work Station, and all accessories
                                                            necessary for the automated
                                                            analysis of gas and LPG samples.
Liquid Autosampler                                          Automatic Sampler for syringable liquid
                                                            materials. Complete with 105 position
                                                            sample holder, 50 sample vials, and 50
                                                            vial caps.
Note: Specifications are subject to change without notice. Precision and accuracy of analyses may be dependent on sample
composition, sample introduction, and system operation.




                                                                                                                     2/2