The present paper demonstrates that electrochemical detection (ECD) coupled to ion chromatography and electrospray ionization tandem mass spectrometry (IC-ECD-ESI/MS/MS) can be used to rapidly estimate some indications of the health status of organisms. The lactulose to mannitol ratio (L/M) is used as anon-invasive assay to investigate small intestinal absorption pathways and mucosal integrity. In the present study, an evaluation of the negative effects of nonsteroidal anti-inflammatory drug meloxicam perorally administrated to a group of dogs was carried out by determining the lactulose/mannitol index using the IC-ECD-ESI/MS/MS hyphenated technique. According to the results of the study, meloxicam altered gastrointestinal permeability. Coenzyme Q10 (CoQ10) was tested to determine if it could prevent meloxicam induced gastrointestinal damage and it was found that CoQ10 could be an effective preventive treatment. Furthermore, plasma glucose concentration level was determined to be an indirect indicator of the oxidative state in the blood. To find out the beneficial effects of a double antioxidant combination (alpha-lipoic acid (ALA) and CoQ10) on the total glucose level in chickens, ALA and CoQ10 were provided as food additives in factory farm raised chicken. The results of the pilot study indicate that the glucose level in the plasma of chickens group fed with CoQ10 and ALA was significantly decreased compared to the control group. Ion chromatography (IC) utilizing pulsed amperometric detection (PAD) was compared to ion chromatography coupled with tandem mass spectrometry (MS/MS) as an analytical tool for monitoring the carbohydrate level in biological fluids. In electrochemical detection, the newly developed two-pulse waveform successfully withstands matrix effects in biological samples. Continuous on-line desalting of the high salt concentrations used as the eluent for carbohydrate separation from the anion-exchange column allows coupling of IC and MS techniques. A make-up solution (0.5 mM LiCl) was delivered prior to MS detection for efficient ionization of eluted carbohydrates. Method validation showed that both used methods are practically comparable and some advantages of each are presented.
COBISS.SI-ID: 4824346
A new two-step potential waveform for pulsed amperometric detection (PAD) of carbohydrates at polycrystalline gold working electrode is described. In contrast to standard triple- and quadruple-potential waveforms, in the two-step potential waveform cathodic electrode conditioning/re-activation is applied exclusively. Waveform consists of cathodic re-activation potential in hydrogen evolution region (from -1.4 V to -2.0 V vs. Ag/AgCl) and detection potential at +0.2 V. The cathodic processes responsible for activation of Au electrode in alkaline medium were characterized by fast scan cyclic voltammetry, chronoamperometry, and chronocoulometry. It was shown that application of the short negative re-activation potential maintains the electrode surface clean and active and completely substitutes oxidative cleaning/activation at potentials higher than +0.3 V used in PAD previously. Both desorptive reduction of the AuOHads and hydrogen evolution reaction play a crucial role in effective cleaning/regeneration of the Au electrode in pulsed sequence. The two-step waveform preserves all analytical properties of three- and four-step potential waveforms and does not result in fouling or dissolution of Au electrode surface in a prolonged use. Square wave sequence substantially simplifies pulsed amperometric detection and enables high frequency sampling required for FIA and capillary IC systems.
COBISS.SI-ID: 4824090
Validation of a method for the quantification of (-)-epicatechin and procyanidin B2 in chocolates is reported. After a simple preparation of the chocolate test solution, thin-layer chromatography (TLC) on high-performance thin-layer chromatographic (HPTLC) cellulose plates with n-propanol-water-acetic acid (20:80:1, v/v/v) and derivatization with 4-dimethylaminocinnamaldehyde were performed. Densitometry at 655 nm enabled accurate quantification of both analytes in chocolates. The milk chocolate sample which served for precision and recovery experiments contained 13.0 mg/100 g of (-)-epicatechin (relative standard deviation (RSD)) 5.8%, n = 6) and 13.2 mg/100 g of procyanidin B2 (RSD 4.2%, n = 6). Usable polynomial curves were 2-30 ng for (-)-epicatechin and 4-60 ng for procyanidin B2. The validated TLC method can be applied for routine quality control of the two major polyphenolic compounds in different chocolate samples.
COBISS.SI-ID: 4854554