Analytical Instrumentation

  • Analysis of Manganese in Gasoline by EDXRF
    Rigaku NEX QC⁺ Energy Dispersive X-ray Fluorescence Analyser

Analysis of Manganese in Gasoline by EDXRF

Dec 11 2019 Read 240 Times

The measurement of manganese (Mn) in gasoline is demonstrated.

Background

Methylcyclopentadienyl manganese tricarbonyl (called MMT or MCMT) is an anti-knock agent added to motor gasoline and Avgas to boost octane rating, replacing tetraethyl lead (TEL) in many regions of the world. In motor gasoline the Mn content is typically between 50-500 mg/kg, and can be as high as 3000 mg/kg (approximately 3 g/L) in Avgas. Reliably characterising the Mn content of gasoline ensures optimum engine performance based on the engine’s compression ratio and other geometrical and mechanical operating conditions. To meet the needs of the industry, Rigaku offers the NEX QC+ analyser, a simple and versatile benchtop EDXRF spectrometer for the analysis of manganese in gasoline.

Instrumentation

Model: Rigaku NEX QC+ 
X-ray tube: 4W Ag-anode 
Detector: SDD 
Sample Type: Gasoline 
Film: Chemplex Etnom (3um) 
Analysis Time: 100 sec 
Environment: Air

Sample Preparation

Ensure each sample is homogeneous and stable. Shake sample gently and allow any bubbles to settle. Fill a 32mm XRF sample cup with 4g of sample to ensure consistent sample depth. Etnom® film (3um) is used, which does not degrade quickly with gasoline or oxygenated gasoline. The sample cup lid must be vented with a small hole to ensure vapor pressure does not build. Due to high evaporation rate of gasoline, it is recommended to make the measurement immediately after filling the cup. [Note: Use of internal standard is not required.]

Calibration

Empirical calibration is made using commercially available certified gasoline calibration standards containing the Mn additive. A typical calibration is demonstrated here for the range 25-500 mg/kg Mn.

See TABLE (Calibration)

Precision

Instrument repeatability (precision) is determined by ten repeat analyses of each sample in static position using a 100 sec analysis time per measurement.

See TABLE (Precision)

Detection Limit

The Lower Limit of Detection (LLD) is defined as three times the standard deviation of ten repeat analyses of a blank gasoline sample containing no Mn. The following typical LLDs are reported here using 100 and 300 sec measurement times.

See TABLE (Detection Limit)

Conclusion

The results shown here indicate the Rigaku NEX QC+ EDXRF analyser can be used to reliably measure Mn in gasoline and Avgas without the need to use an internal standard.

Reader comments

Do you like or dislike what you have read? Why not post a comment to tell others / the manufacturer and our Editor what you think. To leave comments please complete the form below. Providing the content is approved, your comment will be on screen in less than 24 hours. Leaving comments on product information and articles can assist with future editorial and article content. Post questions, thoughts or simply whether you like the content.

Post a Comment




Digital Edition

Petro Industry News November 2019

November 2019

In This Edition Fuel for Thought - Leading European sensor trade event taking place in 2020 already selling out fast - Endress+Hauser and Vector CAG secure contract at large Texas refinery...

View all digital editions

Events

SLAS 2020

Jan 25 2020 San Diego, CA, USA

European Gas Conference

Jan 28 2020 Vienna, Austria

EGYPS (Egypt Petroleum Show)

Feb 11 2020 Cairo, Egypt

Smart Factory Expo (SFE 2020)

Feb 12 2020 Tokyo, Japan

ME-TECH 2020

Feb 18 2020 Abu Dhabi, UAE

View all events