Solid phase extraction-gas chromatography-flame ionization detection (SPE-GC-FID) for the detection of mineral oil saturated hydrocarbons (MOSH) in infant formula

Abstract

Objective: To establish a new accurate method for the determination of mineral oil saturated hydrocarbon （MOSH） in infant formula by solid phase extraction combined with gas chromatography-Flame Ionization Detection （SPE-GC-FID）. Methods: Different extraction methods such as soaking extraction, oscillating extraction, ultrasonic assisted extraction, liquid-liquid extraction were used to extract MOSH from infant formula milk powder, and different extraction solvents such as n-hexane, isooctane, benzene, mixed solvents were used to extract MOSH. The optimal extraction method and extraction solvent were determined based on the extraction amount of MOSH. The target compounds purified by AgNO3 SPE column, and finally detected by gas chromatography-Flame Ionization Detection （GC-FID）. Results: The calibration curve of MOSH was linear in the range of 10.0~1 000 μg/mL with correlation coefficient of 0.999 97. The limit of detection was 1.0 mg/kg, and the limit of quantitation was 3.0 mg/kg. The recoveries from spiked samples were 93.3%~103.7%, and the relative standard deviations were 2.3%~5.9%. The MOSH in 8 commercially available infant formula was detected by the established method, and the results were between 1.06 and 9.83 mg/kg, indicating that there was a certain risk of MOSH contamination in infant formula. Conclusion: This method is accurate, sensitive, and suitable for the detection of MOSH in infant formula.

Keywords

• solid phase extraction
• gas chromatography
• hydrogen flame ionization
• infant formula
• mineral oil saturated hydrocarbons
• ultrasound extraction