An Alternative UV-Vis Spectrophotometric Method for Accurate Quantification of Total Selenium in Se-Enriched...

Area of Science:

• Analytical Chemistry
• Biotechnology

Background:

• Accurate quantification of total selenium (Se) is crucial for assessing its bioavailability and efficacy in Se-enriched microbial biomass.
• Existing methods like ICP-MS are accurate but expensive and inaccessible for many research and industrial settings.

Purpose of the Study:

• To validate a simple, rapid, and cost-effective UV-visible spectrophotometric method for total selenium quantification in Se-enriched microbial biomass.
• To assess the method's reliability and robustness by comparing it with ICP-MS and a certified reference material.

Main Methods:

• Microwave-assisted acid digestion for complete mineralization of organic selenium.
• UV-visible spectrophotometry utilizing the selenium-iodine reaction with starch.
• Validation of linearity, detection/quantification limits, precision, and accuracy using selenized *Lactiplantibacillus plantarum* and *Saccharomyces* spp.

Main Results:

• The method demonstrated good linearity, precision, and accuracy, with recoveries ranging from 97-111% for bacteria and 99-101% for yeast.
• Ultrasonic pretreatment led to overestimation due to interference with the starch-iodine complex.
• Optimal results were achieved at 20 °C, with no ultrasonic pretreatment.

Conclusions:

• The validated UV-visible spectrophotometric method provides accurate total selenium quantification in microbial biomass.
• This protocol is a cost-effective and accessible alternative to ICP-MS for quality control and research applications in the food and biotech industries.