• 

• Culture and Diversity Mission

  History Safety and Health

  FAQ Experience

• 

• Energy Environmental

  Pharmaceutical Research

  Nutraceutical Regulatory Compliance

  Textile Treatment Optimization

• 

• Trace Metals Speciation Total Mercury Analysis Air Method Development

  Halogen Speciation Consulting Tissue Total and Available Cyanide

  Pharmaceutical characterization Wastewater Textiles Treatability Studies

  Trace Metals Analysis Soils Ultrafiltration Method 6800

  Specialty Analytical Services Groundwater Lysimetry Stable Isotopic Ratio Testing

• 

• Our Commitment to Quality Approach to Quality

  Quality Control Certification

  Quality Assurance Laboratory Information Management System (LIMS)

• 

• Chain of Custody Form

  Application Notes

  Statement of Qualifications

  Presentations & Publications

• 

• 

 

 

LINK: Comparison between Hydride Generation and IC-ICP-MS for Selenium Speciation (pdf)

LINK: Trace (ppt level) Total Arsenic and Selenium Analysis (pdf)

LINK: Treatment Plant Optimization for Trace Metal Removal (pdf)

Selenium speciation analysis was performed on a sample generated from a flue gas desulfurization wastewater treatment plant by ion chromatography inductively coupled plasma mass spectrometry (IC-ICP-MS). Quantified species included selenite, selenate, selenocyanate, methylseleninic acid, and selenomethionine.

Sample pretreatment was limited to filtration (0.45 um) without preservation to minimize species conversion prior to analysis. Aliquots of each sample were injected onto an anion exchange column and are mobilized by a basic (pH > 7) gradient. The eluting selenium species were then introduced into the ICP-MS. Various selenium isotopes were monitored to confirm Se in each species. The Se species were identified by matching their retention times to known standards. Chromatograms of a standard mixture and an FGD wastewater sample are presented in Figures.

As part of the Quality Control protocol, four (4) preparation blanks, a certified reference material, matrix duplicate, one matrix spike and matrix spike duplicate set, one analytical duplicate, one analytical spike and analytical spike duplicate, and isotopic monitoring for species confirmation was used. Total selenium analysis via inductively coupled plasma dynamic reaction cell mass spectrometry was also performed for confirmation of the sum of species.

A cursory review of the chromatogram for the FGD discharge identifies that the quantified selenium species account for only a fraction of the total selenium present in the sample. Especially the concentration of selenite and selenate was less than 5% of the total selenium in the sample. At the same there were more than 13 different unidentified peaks which illustrate the extremely complex chemistry of selenium in wastewaters. Although the sum of the identified selenium species did not correlate well with the total selenium analysis by ICP-DRC-MS, integration of all the peaks (unknowns included) comes within experimental error of the total concentration (RPD less than 15%).

Samples from this plant was also analyzed for selenium speciation by a different commercial laboratory using HG-AAS. Unfortunately, the results showed significant biases for Se(IV) which also resulted in biased results for selanate since the Se(VI) concentration is calculated by difference.

This brief study confirms that the complexity of industrial waste, especially from flue gas desulfurization plants, requires a method such as IC-ICP-MS to obtain detailed but most importantly, accurate information and make better decisions.

If you have any questions or would like a quotation, please feel free to email us at info@appliedspeciation.com or call (206) 219-3779.

Feel free to visit our website on a regular basis as we will be providing scientific discussions and useful links to save you time and money.