A novel and eco-friendly analytical method for phosphorus and sulfur determination in animal feed

• Published in: Food chemistry Vol. 246; pp. 422 - 427
• Main Authors: Novo, Diogo L.R., Pereira, Rodrigo M., Costa, Vanize C., Hartwig, Carla A., Mesko, Marcia F.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 25-04-2018
• Subjects: Animal Feed - analysis; Animals; Chromatography, Liquid - methods; Digestion; Diluted acid; Feed safety; Ion chromatography; Microwaves; Minerals determination; Nitric Acid - chemistry; Oxygen - chemistry; Phosphorus - analysis; Sample preparation; Sulfur - analysis; Ion chromatography; Diluted acid; Sample preparation; Minerals determination; Feed safety
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2017.11.036

•Proposed method is an alternative for routine analysis of P and S in animal feed.•High sample masses (500 mg) are digested using only a diluted acid solution.•Suitable digests for ion chromatography analysis was obtained resulting in low LODs.•The proposed method provide a high sample throughput and low waste generation.•The drawbacks of conventional and official methods were overcome.
An eco-friendly method for indirect determining phosphorus and sulfur in animal feed by ion chromatography was proposed. Using this method, it was possible to digest 500 mg of animal feed in a microwave system under oxygen pressure (20 bar) using only a diluted acid solution (2 mol L−1 HNO3). The accuracy of the proposed method was evaluated by recovery tests, by analysis of reference material (RM) and by comparison of the results with those obtained using conventional microwave-assisted digestion. Moreover, P results were compared with those obtained from the method recommended by AOAC International for animal feed (Method nr. 965.17) and no significant differences were found between the results. Recoveries for P and S were between 94 and 97%, and agreements with the reference values of RM were better than 94%. Phosphorus and S concentrations in animal feeds ranged from 10,026 to 28,357 mg kg−1 and 2259 to 4601 mg kg−1, respectively.