title: Application of direct-injection detector integrated with the multi-pumping flow system to chemiluminescence determination of the total polyphenol index.
abstract: In this work, we present a novel chemiluminescence (CL) method based on direct-injection detector (DID) integrated with the multi-pumping flow system (MPFS) to chemiluminescence determination of the total polyphenol index. In this flow system, the sample and the reagents are injected directly into the cone-shaped detection cell placed in front of the photomultiplier window. Such construction of the detection chamber allows for fast measurement of the CL signal in stopped-flow conditions immediately after mixing the reagents. The proposed DID-CL-MPFS method is based on the chemiluminescence of nanocolloidal manganese(IV)-hexametaphosphate-ethanol system. The application of ethanol as a sensitizer, eliminated the use of carcinogenic formaldehyde. Under the optimized experimental conditions, the chemiluminescence intensities are proportional to the concentration of gallic acid in the range from 5 to 350 ng mL(-1). The DID-CL-MPFS method offers a number of advantages, including low limit of detection (0.80 ng mL(-1)), high precision (RSD = 3.3%) and high sample throughput (144 samples h(-1)) as well as low consumption of reagents, energy and low waste generation. The proposed method has been successfully applied to determine the total polyphenol index (expressed as gallic acid equivalent) in a variety of plant-derived food samples (wine, tea, coffee, fruit and vegetable juices, herbs, spices).
authors.affiliation: Department of Analytical Chemistry, Institute of Chemistry, University of Białystok, Hurtowa 1, 15-399 Białystok, Poland. Electronic address: nedyta@uwb.edu.pl.
authors.forename: Edyta
authors.initials: E
authors.lastname: Nalewajko-Sieliwoniuk
authors.affiliation: Department of Analytical Chemistry, Institute of Chemistry, University of Białystok, Hurtowa 1, 15-399 Białystok, Poland.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Iwanowicz
authors.affiliation: Department of Chemistry, University of Warmia and Mazury, 10-957 Olsztyn, Poland.
authors.forename: Sławomir
authors.initials: S
authors.lastname: Kalinowski
authors.affiliation: Department of Analytical Chemistry, Institute of Chemistry, University of Białystok, Hurtowa 1, 15-399 Białystok, Poland.
authors.forename: Anatol
authors.initials: A
authors.lastname: Kojło
mesh_terms: D001628:Beverages / Q000032:analysis; D049449:Luminescence; D059808:Polyphenols / Q000032:analysis*
chemical_list: D059808:Polyphenols
keywords: Chemiluminescence; Direct-injection detector; Green analytical chemistry; Multi-pumping flow system; Nanocolloidal manganese(IV); Polyphenolic antioxidants