Microwave Digestion of Plant and Grain Reference Materials in Nitric Acid or a Mixture of Nitric Acid or a Mixture of Nitric Acid and Hydrogen Peroxide for the Determination of Multi-elements by Inductively Coupled Plasma Mass Spectrometry

1997 ◽  
Vol 12 (8) ◽  
pp. 797-806 ◽  
Author(s):  
SHAOLE WU ◽  
XINBANG FENG ◽  
ADOLPH WITTMEIER
Keyword(s):  
Mass Spectrometry ◽  
Hydrogen Peroxide ◽  
Nitric Acid ◽  
Reference Materials ◽  
Inductively Coupled Plasma ◽  
Microwave Digestion ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry

Simultaneous determination of ultra-trace Pt, Pd, Rh and Ir in geochemical samples by inductively coupled plasma mass spectrometry following tin fire assay preconcentration and microwave digestion

2020 ◽  
Vol 16 ◽  
Author(s):  
Wenshan Ni ◽  
Xiangju Mao ◽  
Hongli Zhang ◽  
Lu Liu ◽  
Xiaorui Guo ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Nickel Oxide ◽  
Inductively Coupled Plasma ◽  
Lead Oxide ◽  
Microwave Digestion ◽  
Fire Assay ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry ◽  
Ultra Trace

Background: Platinum (Pt), palladium (Pd), rhodium (Rh) and iridium (Ir) are platinum group elements (PGEs) and also important elements of geochemistry and environmental chemistry with the similar physic-chemical properties, which have been widely used in industry and laboratory. However, due to the low abundance and inhomogeneous distribution in natural ore as well as the nugget effect, the accurate determination of PGEs has been a challenge to analytical chemistry. Methods: In this work, a novel fire assay method was reported for the determination of ultra-trace Pt, Pd, Rh and Ir in geochemical samples. Tin powder (Sn) instead of stannic oxide (SnO2) was used as fire assay collector to reduce the melting temperature from 1250 oC to 1050 oC, the escape of molten material caused by high temperature was successfully avoided. Tin bead was compressed into thin slice and dissolved by HCl. For the target Pt, Pd, Rh and Ir, HCl insoluble substance such as PtSn4, PdSn4, RhSn4 and Ir3Sn7 were formed and separated from matrix by filtering. The metal compounds precipitate together with filter paper were microwave-assisted completely digested by aqua regia (50%, v/v), thence the sample solution were determined by inductively coupled plasma mass spectrometry (ICP-MS). Results: Compared with nickel oxide and lead oxide in nickel sulfide /lead fire assay, the reagent blank of tin powder were relatively low and could be directly employed in tin fire assay to collect Pt, Pd, Rh and Ir without purifying. Moreover, the harm of nickel oxide and lead oxide to the analyst and environment was avoided by using the non-toxic tin powder. The decomposition method of chromite and black shale were investigated as well as the amount of tin powder and flour, microwave digestion program for the determination of Pt, Pd, Rh and Ir were optimized. Besides, the influence of mass spectrum interference of co-existing elements was discussed and the standard mode and kinetic energy discrimination collision pool mode were compared. Under the optimal conditions, excellent curve fitting of Pt, Pd, Rh and Ir were obtained between 0.01～100 ng mL-1 , with the correlation coefficients exceeding 0.9996. The detection limits were from 0.003 ng g -1 to 0.057 ng g -1 . Conclusion: The developed method was applied to analyze the Chinese Certified Reference Materials and the determined values were in good agreement with the certified values.

Method for the Determination of Total Selenium in a Wide Variety of Foods Using Inductively Coupled Plasma/Mass Spectrometry

2013 ◽  
Vol 96 (4) ◽  
pp. 786-794 ◽  
Author(s):  
Darryl Sullivan ◽  
Richard Zywicki ◽  
Mark Yancey
Keyword(s):  
Nitric Acid ◽  
Infant Formula ◽  
Inductively Coupled Plasma ◽  
Microwave Digestion ◽  
High Volume ◽  
Powdered Infant Formula ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry ◽  
Total Selenium

Abstract An optimized method for use in a high volume laboratory was developed and validated for the determination of total selenium in a wide variety of food products including infant formula. The method utilizes a single-stage, closed-vessel microwave digestion procedure with nitric acid. Upon completion of digestion, the solution is brought to volume with water. A dilution is prepared for analysis by adding methanol (MeOH) to an aliquot and then brought to volume by nitric acid diluent resulting in a 3% MeOH concentration. The amount of selenium is determined by inductively coupled plasma (ICP)/MS with the capability of removing argon-based polyatomic interferences. Experiments were conducted to validate the method by determining precision, accuracy, linearity, specificity, ruggedness, and robustness. The calculated practical reporting level for this method was 25.0 μg/kg. The method provided an average RSD of 2.03% during analysis of a wheat flour reference material and 2.73% during analysis of a powdered infant formula. The accuracy of the method for these materials was 98.6 and 105%, respectively. The method has also been used successfully on a variety of foods from various categories including fruits, grains, vegetables, protein, and dairy.

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