title: Analysis of a series of chlorogenic acid isomers using differential ion mobility and tandem mass spectrometry.
abstract: Chlorogenic acids are among the most abundant phenolics found in the human diet. Of these, the mono-caffeoylquinic acids are the predominant phenolics found in fruits, such as apples and pears, and products derived from them. In this research, a comprehensive study of the electrospray ionization (ESI) tandem mass spectrometric (MS/MS) dissociation behavior of the three most common mono-caffeoylquinic acids, namely 5-O-caffeoylquinic acid (5-CQA), 3-O-caffeoylquinic acid (3-CQA) and 4-O-caffeoylquinic acid (4-CQA), were determined using both positive and negative ionization. All proposed structures of the observed product ions were confirmed with second-generation MS(3) experiments. Similarities and differences between the dissociation pathways in the positive and negative ion modes are discussed, confirming the proposed structures and the established MS/MS fingerprints. MS/MS dissociation was primarily driven via the cleavage of the ester bond linking the quinic acid moiety to the caffeic acid moiety within tested molecules. Despite being structural isomers with the same m/z values and dissociation behaviors, the MS/MS data in the negative ion mode was able to differentiate the three isomers based on ion intensity for the major product ions, observed at m/z 191, 179 and 173. This differentiation was consistent among various MS instruments. In addition, ESI coupled with high-field asymmetric waveform ion mobility spectrometry-mass spectrometry (ESI-FAIMS-MS) was employed for the separation of these compounds for the first time. By combining MS/MS data and differential ion mobility, a method for the separation and identification of mono-caffeoylquinic in apple/pear juice samples was developed with a run time of less than 1 min. It is envisaged that this methodology could be used to identify pure juices based on their chlorogenic acid profile (i.e., metabolomics), and could also be used to detect juice-to-juice adulteration (e.g., apple juice addition to pear juice).
authors: Department of Food and Bioproduct Sciences, College of Agriculture and Bioresources, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK, S7N 5A8, Canada.
authors: Jamie L
authors: JL
authors: Willems
authors: Drug Design & Discovery Group, College of Pharmacy and Nutrition, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK, S7N 5E5, Canada.
authors: Mona M
authors: MM
authors: Khamis
authors: Drug Design & Discovery Group, College of Pharmacy and Nutrition, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK, S7N 5E5, Canada.
authors: Waleed
authors: W
authors: Mohammed Saeid
authors: Crop Development Centre, College of Agriculture and Bioresources, 51 Campus Drive, Saskatoon, S7N 5A8, Canada.
authors: Randy W
authors: RW
authors: Purves
authors: Canadian Centre for Health and Safety in Agriculture (CCHSA), and Department of Medicine, University of Saskatchewan, 104 Clinic Place, Saskatoon, SK, S7N 2Z4, Canada.
authors: George
authors: G
authors: Katselis
authors: Department of Food and Bioproduct Sciences, College of Agriculture and Bioresources, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK, S7N 5A8, Canada.
authors: Nicholas H
authors: NH
authors: Low
authors: Drug Design & Discovery Group, College of Pharmacy and Nutrition, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK, S7N 5E5, Canada. Electronic address: anas.el-aneed@usask.ca.
authors: Anas
authors: A
authors: El-Aneed
mesh_terms: D002726:Chlorogenic Acid / Q000032:analysis*; D000075663:Ion Mobility Spectrometry; D015394:Molecular Structure; D013237:Stereoisomerism; D053719:Tandem Mass Spectrometry
chemical_list: D002726:Chlorogenic Acid
keywords: Chlorogenic acid isomers; Differential ion mobility; Tandem mass spectrometry