Determination of L-carnitine in milk and dairy products by hydrophilic liquid chromatography-tandem mass spectrometry

Abstract

An analytical method was developed for the determination of L-carnitine in milk and dairy products using hydrophilic interaction chromatography-tandem mass spectrometry (HILIC-MS/MS). The samples were extracted with 2% (v/v) acetic acid solution, and the protein was precipitated with acetonitrile subsequently. The separation of L-carnitine was carried out on an Acquity UPLC BEH HILIC column using ammonium acetate and acetonitrile as mobile phases. The quantification analysis of the target compound was performed under multiple reaction monitoring (MRM) mode by external standard method. A good linear relationship was obtained between the peak area and concentration of L-carnitine in the range of 1-100 µg/L with the correlation coefficient more than 0.99. The limit of quantification (LOQ ) of L-carnitine was 0. 01 mg/kg. The spiked recoveries were 96.0%-103.4%. The precisions (RSDs ) were 1.2%-4.3%. The sample preparation was simple and rapid, and the results were precise and sensitive. The developed method is suitable for the study of concentration of L-carnitine in milk and dairy products, and the technical support for the infant formula is provided.

Identification of l‐carnitine and its impurities in food supplement formulations by online column‐switching liquid chromatography coupled with linear ion trap mass spectrometry

“…Another impurity CTTA was not quantified because the standard is unavailable. Numerous reports on analytical methods for determination of l‐ carnitine in biological samples (plasma, serum, and urine), food supplements and pharmaceutical formulations have been published , but there are few reports on determining the impurities in l‐ carnitine. CTEA (crotonoylbetaine) was detected in pharmaceutical formulations of l‐ carnitine by ion pairs HPLC–UV, with the content at < 1% .…”

“…In the United States Pharmacopeia (http://www.pharmacopeia.cn/v29240/usp29nf24s0_m44704.html), a heptanesulfonate ion‐pairing mobile phase (containing phosphate buffer) with methanol is used in HPLC for quantitative determination of l‐ carnitine in oral solutions and tablet formulations. Other columns, such as HILIC columns, have also been used to determine carnitine and acylcarnitines in milk, human urine, serum, and plasma . A CN analytical column was used for analysis of piracetam and l‐ carnitine in human plasma .…”

Derivative spectrophotometric for simultaneous estimation of propranolol hydrochloride and hydrochlorothiazide in synthetic mixture

“…The Simultaneous Determination of Propranolol Hydrochloride and Isosorbide Mononitrate was done by Central Composite Rotatable Design (Khan et al, 2019). Some another methods were used, such as LC-MSIMS (Johannsen et al, 2019;Li and Hongbin, 2018). The present study aims to develop a new spectrophotometric method for simultaneously estimation of PRO and HCTZ by a irst derivative method in pure form and in their synthetic mixture.…”