Undeclared (Poly)phosphates Detection in Food of Animal Origin as a Potential Tool toward Fraud Prevention.

(Poly)phosphates are approved as water-preserving and emulsifying agents that improve the appearance and consistency of many food products. The labelling of added (poly)phosphates is essential for protecting vulnerable population groups and to prevent unfair trade practices resulting in economic fraud. The problems with (poly)phosphates' utilisation concerns both analytical and legislative issues, such as: (1) their straightforward detection; (2) excessive addition altering freshness perception and misleading consumers; (3) uncontrolled usage increasing foodstuff weight; (4) application in products where they are not permitted; and (5) no indication on the label. Bearing all these issues in mind, the main purpose of this study was the quantification and screening of the (poly)phosphates profile in meat, marine and dairy products (160 samples), of which 43 were without declared (poly)phosphate treatment. Analysis was completed by high-performance ion-exchange chromatography either with conductometric detection or coupled to Q-Exactive Orbitrap high-resolution mass spectrometry. Although the (poly)phosphates profiles varied greatly according to species and processing type, the following criteria for detection of illicit treatment were established: high orthophosphate level, quantified short-chain (poly)phosphate anions and the presence of long-chain forms. In conclusion, the instrumental platforms used in this study can be recommended to inspection bodies as reliable methods for the detection of food adulteration with (poly)phosphates.

Fast analysis of quaternary ammonium pesticides in food and beverages using cation-exchange chromatography coupled with isotope-dilution high-resolution mass spectrometry.

A fast separation based on cation-exchange liquid chromatography coupled with high-resolution mass spectrometry is proposed for simultaneous determination of chlormequat, difenzoquat, diquat, mepiquat and paraquat in several food and beverage commodities. Solid samples were extracted using a mixture of water/methanol/formic acid (69.6:30:0.4, v/v/v), while liquid samples were ten times diluted with the same solution. Separation was carried out on an experimental length-modified IonPac CS17 column (2 × 15 mm2 ) that allowed the use of formic acid and acetonitrile as mobile phase. Detection limits for food and beverage matrices were established at 1.5 µg/L for chlormequat, difenzoquat and mepiquat, and 3 µg/L for diquat and paraquat, while for drinking water a pre-analytical sample concentration allowed detection limits of 9 and 20 ng/L, respectively. Precision, as repeatability (RSD%), ranged from 0.2 to 24%, with a median value of 6%, and trueness, as recovery, ranged from 64 to 118%, with a median value of 96%. The method developed was successfully applied to investigate the presence of herbicide residues in commercial commodities (mineral water, orange juice, beer, tea, green coffee bean, toasted coffee powder, cocoa bean, white corn flour, rice and sugar samples).

Separation and characterisation of beta2-microglobulin folding conformers by ion-exchange liquid chromatography and ion-exchange liquid chromatography-mass spectrometry.

In this work we present for the first time the use of ion-exchange liquid chromatography to separate the native form and a partially structured intermediate of the folding of the amyloidogenic protein beta2-microglobulin. Using a strong anion-exchange column that accounts for the differences in charge exposure of the two conformers, a LC-UV method is initially optimised in terms of mobile phase pH, composition and temperature. The preferred mobile phase conditions that afford useful information were found to be 35 mM ammonium formate, pH 7.4 at 25°C. The dynamic equilibrium of the two species is demonstrated upon increasing the concentration of acetonitrile in the protein sample. Then, the chromatographic method is transferred to MS detection and the respective charge state distributions of the separated conformers are identified. The LC-MS results demonstrate that one of the conformers is partially unfolded, compared with the native and more compact species. The correspondence with previous results obtained in free solution by capillary electrophoresis suggest that strong ion exchange LC-MS does not alter beta2-microglobulin conformation and maintains the dynamic equilibrium already observed between the native protein and its folding intermediate.

Time-resolved measurement of the ionic fraction of atmospheric fine particulate matter.

From the health stand-point, atmospheric particulate matter (PM) is regulated through PM(10) and PM(2.5) conventions by the Directive 2008/50/EC. The Directive points out the negative impact on human health due to PM(2.5) and recognizes that no threshold has been identified for such pollutant at which no risk is foreseen for the population. Then, the goal is to pursue a general reduction of PM(2.5). Traditionally, the analytical techniques used to monitor the PM water-soluble inorganic ionic fraction involve filter-based procedures to collect, process, and analyze samples. Data obtained, while accurate, lack temporal resolution. Time resolution is required on the time-scale of the evolution of the planetary boundary layer to understand the processes that govern transport and transformation of atmospheric aerosol. In this paper, we investigated PM(2.5) nitrite, nitrate, sulfate, chloride, sodium, ammonium, calcium, and magnesium ions using a URG 9000-D aerosol ion monitor with 1-h time-resolution and detection limit of 0.1 microg/m(3). The gas phase is separated from the aerosol phase with a liquid diffusion parallel-plate denuder. Daily trends of the pollutants measured in downtown Rome are discussed and interpreted with reference to atmospheric conditions.

Study of molar response of dextrans in electrochemical detection.

In this work, a methodological approach is reported, aimed at assessing the electrochemical response of some model gluco-oligosaccharides (dextrans). Such strategy is based on the complementary use of both anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) and capillary zone electrophoresis coupled with UV detection (CZE-UV). Unlike HPAEC-PAD, CZE-UV required derivatization with a chromophoric dye (i.e., 8-aminonaphtalene-1,3,6-trisulphonic acid, ANTS) to enhance UV response and separation selectivity. From the comparison between chromophore response and PAD signal, the reliability of HPAEC-PAD for quantitative evaluation of dextran mixtures containing mainly oligomers with polymerization degree (DP) up to 18 could be proved, due to the fairly constant molar response. For higher DPs (up to 41), a maximum in the trend of the molar responses was observed followed by a steep decrease for DPs higher than about 30-35; indeed, an underestimation of weight-average molecular weight of dextran mixtures containing such oligomers was noticed.

Ion chromatography applications in the determination of HF, HCl, NOx, SOx on stationary emissions.

In this work, specific topics will be covered in order to verify an effective, routine application of ion chromatography as a suitable and approved technique for emission monitoring in the determination of HF, HCl, NOx and SOx on stationary emission. A review of the analytical methods as proposed by recent updates in Italian environmental law and the problems encountered in the application of this method, such us the interference due to high level of carbonate, high hydroxides concentration particularly on SOx and NOx absorbing solution, are considered in the present work. The sample treatments before the IC analysis, this to reduce the matrix interference due to the strong basic solutions used to monitor different stationary emissions, are also examined. Some modifications in sampling are explored to find more suitable conditions for the IC analysis.