Simultaneous determination of five phosphates in dairy products by ion chromatography

Abstract

A simple and reliable analytical method was established for the quantitative determination of five phosphates (orthophosphate, pyrophosphate, trimetaphosphate, tripolyphosphate, and hexametaphosphate) in dairy products by ion chromatography (IC). The samples were deproteinized with 2% trifluoroacetic acid, defatted with n-hexane, and then purified on a C18 solid phase extraction cartridge. Five phosphates were separated on an IonPac^TM AS11-HC analytical column (250 mm × 2 mm) and an IonPac^TM AG11-HC guard column (50 mm × 2 mm) with gradient elution of 30-60 mmol/L NaOH, then detected by a suppressor type conductivity detector. The peak areas were linearly valuated with the concentration of the five compounds with good linear coefficients (not less than 0.9986). The limits of detection ranged from 0.1 mg/L to 0.6 mg/L. The average recoveries were within the range of 83.0–117.8% with the RSDs below 9.0%. The concentration of the five phosphates in the treated samples remained relatively stable within 48 h. The proposed procedure has been applied to the determination of the five analytes in several dairy product samples with satisfactory results.

Graphical Abstract

Keywords:

• Dairy products
• ion chromatography
• phosphates

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was financially supported by the National Key Research and Development Project of China [No. 2018YFC1604306] and the Science and Technology Innovation Platform Project of Jiangxi Province [No. 20192BCD40001], China.