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Ambient mass spectrometry has been used for the analysis of strobilurin residues in wheat. The use of this novel, challenging technique, employing a direct analysis in a real time (DART) ion-source coupled with a time-of-flight mass spectrometer (TOF MS) and a desorption electrospray ionization (DESI) source coupled with a linear ion trap tandem MS (LIT MS'), permitted a direct screen of the occurrence of target fungicides in treated grains in less than 1 min. For quantification purpose by DART-TOF MS, an ethyl acetate extract had to be prepared. With the use of a prochloraz as an internal standard, the performance characteristics obtained by repeated analyses of extract, spiked at 50 [micro]g [kg.sup.-1] with six strobilurins (azoxystrobin, picoxystrobin, dimoxystrobin, kresoxim-methyl, pyraclostrobin, and trifloxystrobin), were in the following range: recoveries 78-92%, repeatability (RSD) 8-15%, linearity ([R.sup.2]) 0.9900-0.9978. The analysis of wheat with incurred strobilurin residues demonstrated good trueness of data generated by the DART-TOF MS method; the results were in a good agreement with those obtained by the conventional approach, i.e., by the QuEChERS sample handling procedure followed by identification/quantification employing high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Tandem mass spectrometry using DESI-LIT [MS.sup.n] provided a sufficient number of product ions for confirmation of the identity of azoxystrobin and pyraclostrobin in incurred wheat samples.

BACKGROUND: The production and consumption of chicken has doubled in the last 17 years. Since slaughter yields range from 70 to 80%, during production various chicken waste residues are generated. One of these residues is waste created after the mechanical separation of chicken meat (W‐MSM). The goal of the circular economy is to manage this waste and transform it into a valuable product. RESULTS: W‐MSM was subjected to hydrolysis by the proteolytic enzymes pepsin and papain to obtain bioactive compounds. Papain digestion resulted in several times higher yields of chondroitin sulfate (CS), hyaluronic acid (HA), peptides and amino acids in comparison with pepsin. The hydrolysis conditions were further optimized using the software Design Expert to evaluate the impact of added enzyme, buffer and duration of the hydrolysis. In addition, the scale‐up of this process was verified with 5 kg of W‐MSM and the obtained product contained approximately 77% (w/w) of peptides, 9% (w/w) of CS, 7% (w/w) of HA and 4% (w/w) of amino acids. CONCLUSIONS: We tested and optimized the method for evaluating the direct waste from poultry processing and transformed it into a product containing bioactive compounds which can be utilized as an ingredient for improving the properties of feed. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the applicability of different calibration approaches in a multi- and single-residue analysis of modern pesticides in plant matrices using liquid chromatography-electrospray mass spectrometry (HPLC-ESI-MS). In the first set of experiments the determination of eight pesticides representing different groups of polar/unstable pesticides (carbamates, benzimidazoles, azoles, benzoylphenylurea) in apple samples was performed. The trueness and precision of data obtained by using: (i) external solvent standard calibration, (ii) external matrix-matched standard calibration and (iii) echo-peak internal standard calibration was compared. The last mentioned method is a novel technique providing the possibility to inject internal standard of the same identity as a target analyte, so that its retention time is close to the analyte from the sample. According to expectation, when using external standard solvent calibration the results were under- or overestimated due to suppression or enhancement of analyte's signal by matrix components. On the other hand with the use of matrix-matched calibration accurate data were obtained. With echo-peak technique accurate results comparable to those obtained by matrix calibration were obtained for six out of eight pesticides. In the second set of experiment we used the echo-peak technique to overcome the problem with the response instability in the analysis of chlormequat in pear concentrate samples. As an internal standard method the echo-peak technique provided the possibility of monitoring of signal decrease during the analytical sequence and to compensate this decrease by relating sample peak area relatively to this internal standard.