High-performance liquid chromatographic detection of selected phenolic acidsin wine

The aim of this study was to develop a method for identification and quantification of phenolic acids in different wine samples. The simple reversed-phase HPLC-UV method for simultaneous determination of p-coumaric and ferulic acid was developed. The method was validated and working range, linearity, repeatability, accuracy, limit of quantitation LOQ and limit of detection LOD were determined. The linearity of the method was tested in concentration ranges 0.1-1 mg L-1 and 1-10 mg L-1. The correlation coefficients (r2) were greater than 0.996 and quality coefficients (QC) ≤ 5%. Detection limit for both compounds was 0.01 mg L-1. The method is precise (RSD

A rapid reversed-phase thin layer chromatographic detection protocol for adulteration in some edible fats and oils food formulation

The problems of adulteration in the vegetable oil and fat have been the major draw backs in the food products formulation, in spite of the various adulteration detection methods in different applications that have been reported. However, the detection tools that can be fast and reliable for the routine analysis necessitated the current work. The two groups of three different samples: vegetable fat containing sample (Blue Band, Golden Penny, La Prairie Classic) and animal fat containing samples (Kell Salad Cream, Crosse & Blackwell and Nola) was used for the purity check using the reversed phased - thin layer chromatographic (RPTLC) method of analysis were developed. The average Rf ratio of 0.95 and 0.92, found for the vegetable and animal fat groups were reported, respectively. The Rf = 0.03 difference between the two groups indicated the presence of sistosterol (plant sterol) and cholesterol (animal sterol), an improvement over color detection methods to screen oils and fats to ascertain purity. Keywords: Sistosterol, Cholesterol, Adulteration, Animal fat, Vegetable oil

4-hour immuno-chromatographic detection of intestinal carriage of carbapenemase-producing Enterobacteriaceae: a validation study

Background. The increasing incidence of Carbapenemase-Producing Gram-Negative Bacilli (C-PGNB) represents a major public health challenge. Rapid detection of the digestive colonization with C-PGNB is fundamental to control their spread. Aim. Validation of a rapid protocol for C-PGNB detection directly on rectal swabs. Methods. We developed a protocol combining enrichment by a rapid selective subculture of the rectal swab medium and realization of a Resist-4 OKNV K-SeT® test on the bacterial pellet so obtained. The limit of detection and performances of this protocol were validated in vitro on 52 C-PGNB strains spiked on calibrated sample suspension; and confirmed in clinical settings on 144 rectal swabs sampled from patients with C-PGNB digestive colonization (n=48) and controls (patients with ESBL colonization (n=48) and without carbapenemase/ESBL (n=48)). Results. The protocol detected with 100% sensitivity the presence of the 15 OXA-48-, 14 KPC-, 13 NDM- and 10 VIM-producing GNB from 103 CFU/mL. The limit of detection was 2.102 CFU/mL. Among the 48 C-PGNB containing rectal swabs of the validation cohort, 46 were accurately detected. False negative were observed for 1 NDM-producing Acinetobacter baumanii and 1 OXA-48-producing E. coli. The 96 control swabs were negative. Sensitivity and specificity for C-PGNB detection were 97.7% 95%CI(87.7-100) and 100% 95%CI(96.2-100). The negative likelihood ratio was 0.04 95%CI(0.01-0.16). Considering a C-PGNB digestive colonization prevalence between 0.01% and 0.1%, positive and negative predictive values were 100%. Conclusion. Our protocol is a rapid and low-cost method detecting accurately the digestive colonization with C-PE in 4 hours without any requirement for specific equipment.

Ultra Rapid and Highly Sensitive Disperser-less Liquid-liquid Microextraction of Organophosphate Pesticides Prior to Gas Chromatography with Mass Spectrometry Detection

Background: Organophosphates (OPPs) are toxic chemicals that can cause serious health problems through poisoning water and food. Objectives: A very simple and fast disperser-less liquid microextraction strategy before chromatographic detection was designed for the analysis of organophosphates in various water solutions. Methods: A 60 µL aliquot of chloroform, as extraction solvent (without using disperser), was introduced into the sample solution by rapid injection, and the sedimented organic phase was analyzed to assay some organophosphates. Results: Analytical characteristics, including limits of detection (0.0003 - 0.001 µg.L-1), linear dynamic ranges (0.001 - 100 µg.L-1), relative standard deviations (2.5 - 10), enrichment factors (up to 238), and extraction recoveries (84% - 108%), indicated the high efficacy of the developed method for analyzing the target analytes. Conclusions: The proposed procedure was effectively used for the analysis of the OPPs in real tap water, river water, and fruit juice samples. In the present study, the examined analytes were in the range of 0.07 - 1.56 µg.L-1.