Water-soluble vitamins, as essential micronutrients for the human body, play a vital role in maintaining normal physiological functions, and their deficiency may lead to metabolic disorders and related health issues. Infant formula is fortified with these vitamins through nutrient fortification technologies to support the healthy growth and development of infants and young children. Due to the matrix complexity of infant formula and the instability of water-soluble vitamins, it is a great challenge to accurately analyze and detect multiple water-soluble vitamins in infant formula. In this paper, we review the latest developments in extraction and separation (protein precipitation, acid hydrolysis, and enzymatic hydrolysis) and detection (microbiological method, liquid chromatography, and liquid chromatography-mass spectrometry) techniques for water-soluble vitamins in infant formula, and we discuss future prospects in this field. Through this review, we aim to provide a reference for relevant researches.

A novel efficient and accurate ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the detection of 13 diuretics in animal-derived foods was developed. The samples were extracted with acetonitrile or 90% acetonitrile solution and cleaned up on a PRiME HLB pass-through solid phase extraction (SPE) column. Then, an ACQUITY HSS T3 column (100 mm × 2.1 mm, 1.8 μm) was used for chromatographic separation by gradient elution using a mobile phase consisting of 5 mmol/L aqueous ammonium acetate and acetonitrile, and an electrospray ionization source (ESI) operated in both positive and negative ion scanning modes with multiple reaction monitoring (MRM) was used to detect the diuretics qualitatively and quantitatively. The results showed that the calibration curves for all the analytes exhibited good linearity with correlation coefficients above 0.9970. The limits of quantification ranged from 2.0 to 5.0 μg/kg. The recoveries of the proposed method ranged between 68.3% and 118.0%, with relative standard deviations (RSDs) between 0.47% and 9.5% (n = 6). This method is a fast, simple, accurate, and practical one for the detection of diuretics.