Total Iodine in Infant Formula and Adult/Pediatric Nutritional Formula Using Inductively Coupled Plasma-Mass Spectrometry: AOAC Official First Action 2012.15

2013 ◽  
Vol 96 (3) ◽  
pp. 493-496 ◽  
Author(s):  
Darryl Sullivan ◽  
Richard Zywicki ◽  
Dawn Dowell
Keyword(s):  
Mass Spectrometry ◽  
Infant Formula ◽  
Inductively Coupled Plasma ◽  
Total Iodine ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry ◽  
Aoac Official

Determination of Total Iodine in Infant Formula and Nutritional Products by Inductively Coupled Plasma/Mass Spectrometry: Single-Laboratory Validation

2012 ◽  
Vol 95 (1) ◽  
pp. 169-176 ◽  
Author(s):  
Lawrence H Pacquette ◽  
Alan M Levenson ◽  
Joseph J Thompson
Keyword(s):  
Mass Spectrometry ◽  
Infant Formula ◽  
Inductively Coupled Plasma ◽  
Control Sample ◽  
Microwave Oven ◽  
Standard Reference Materials ◽  
Total Iodine ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry ◽  
Single Laboratory

Abstract A single-laboratory validation by inductively coupled plasma-mass spectrometry was developed for the determination total iodine (m/z 127) in infant formula and adult nutritional products. All samples were digested in nitric acid using a closed vessel microwave oven system; Te (m/z 130) was used as an internal standard. To prevent loss of iodine, ammonium hydroxide solution was added to the samples immediately after digestion. The method quantitation limit for total iodine was 0.3 ng/mL, but a practical LOQ was used at 1.0 ng/mL, a concentration at which there was a negligible bias due to nonlinearity. The total iodine concentrations (112–1900 ng/g) in 14 out of 15 nutritional products were within specification limits. Within-day and day-to-day (6 independent days) precision values were <10% RSD. The observed precision for the overall mean (18 independent days) of a control sample was approximately 4% RSD. In two National Institute of Standards and Technology standard reference materials, total iodine results were within certified limits. Sample spike recoveries for all 15 nutritional products were 92–105%. The data show that a conventional microwave oven digestion procedure can be used to prepare samples for iodine determination. Therefore, this technique is very compatible with other methods being proposed as modern official methods for the analysis of minerals in nutritional products.

Total Iodine in Infant Formula and Nutritional Products by Inductively Coupled Plasma/Mass Spectrometry: First Action 2012.14

2013 ◽  
Vol 96 (4) ◽  
pp. 798-801 ◽  
Author(s):  
Lawrence H Pacquette ◽  
Alan M Levenson ◽  
Joseph J Thompson ◽  
Dawn Dowell
Keyword(s):  
Infant Formula ◽  
Inductively Coupled Plasma ◽  
Internal Standard ◽  
Total Iodine ◽  
Method Performance ◽  
Inductively Coupled ◽  
Expert Review ◽  
Performance Requirements ◽  
Expert Review Panel ◽  
Plasma Mass Spectrometry

Abstract After an assessment of data generated from a single-laboratory validation study published in the Journal of AOAC INTERNATIONAL 95, 169–176 (2012), a method for determining the total level of iodine in infant formula and nutritional products was presented for consideration for adoption by AOAC during the AOAC Annual Meeting held September 30–October 3, 2012 in Las Vegas, NV. An Expert Review Panel on Infant Formula and Adult Nutritionals concluded that the method met the established standard method performance requirements, and approved the method as AOAC Official First Action. The method involves digestion of the sample with nitric acid in a closed vessel microwave oven, followed by determination by inductively coupled plasma/MS using tellurium as the internal standard. The method LOQ for total iodine was 1.5 μg/100 g, but a practical LOQ was used at 5 μg/100 g total iodine. The analytical range of the method was 5–100 μg/100 g total iodine. The recoveries from 15 spiked nutritional products ranged from 90 to 105%.

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