Use of a deactivated PTV injector liner and GCMS/MS for the quantitative determination of multiple pesticide residues in fruit and vegetables.

The quantitative determination of multiple pesticide residues in food is an iterative process given the frequent changes in monitoring specifications set by regulatory authorities, introduction of new pesticide active ingredients, variety of commodities encountered and advances in the capability of analytical instrumentation and software platforms. The method described here:•replaces our previous methodology [1] that was based on an ethyl acetate extraction [2], two different sample extract clean-up regimes depending on the commodity; either Gel Permeation Chromatography (GPC) or Solid Phase Extraction (SPE) and GC/MSMS analysis using cool on-column injection and permits higher throughput using the same QuEChERS extraction method used for LCMS/MS analysis [3]•uses PTV injection incorporating a deactivated (baffled) injection liner required to improve performance for 'difficult to analyse' pesticides e.g. captan, dichlofluanid, folpet, tolylfluanid.•has been validated for the quantitative determination of 113 different pesticides and their metabolites in a range of fruit and vegetables of high water content and high acid and high water content i.e. cabbage, lemon, pepper, plum and spinach and complies with requirements of European Commission guidance document on Analytical Quality Control and Method Validation Procedures for Pesticides Residues Analysis in food and feed - SANTE/12682/2019 [4].

Preparation of KI/Hydroxyapatite Catalyst from Phosphate Rocks and Its Application for Improvement of Biodiesel Production.

The main aim of this work was to investigate the suitability of a KI/KIO3 impregnated hydroxyapatite (HAP) catalyst derived from natural phosphate rocks for biodiesel production. This study evaluated the effect of impregnation concentrations (1-6% w/w) on the catalyst performance in biodiesel production. The biodiesel was produced from waste cooking oil (WCO) under simultaneous esterification-transesterification reactions at 60 °C for 6 h. The results showed that the biodiesel yield increased by increasing impregnation concentration and the maximum yield (91.787%) was achieved at an impregnation concentration of 5% w/w. The KI/HAP catalyst showed better performance (91.78% biodiesel yield, 59.1% FAME yield and surface area of 13.513 m2/g) as compared to the KIO3/HAP catalyst (90.07% biodiesel yield, 55.0% FAME yield and surface area of 10.651 m2/g).

Computational study of Simultaneous synthesis of optically active (RS)-1,2,4-butanetriol trinitrate (BTTN).

In respective water or ethanol polarizable continuum cavity environments, simultaneous aldol condensation was performed using density functional theory (DFT) computational method to model the synthesis of optically active (RS)-1,2,4-butanetriol trinitrate (BTTN). The results of reaction energy barrier analysis suggested feasible routes with lower activation energies to obtain either the (R)- or (S)-configuration product in ethanolic solution. In addition, local analysis of average inter-particulate distances of reaction species revealed that a stronger inter-particulate interaction accompanied a shorter average distance in the ethanol system. The stabilization effect also indicated that related syntheses would be able to proceed in ethanol. Furthermore, relative to the production of (R)-BTTN, a lower overall energy of 425.3 kJ/mol was required for the synthesis of (S)-BTTN. Through analysis of the effects of temperature on the reaction rates of individual parallel stages of (R)- and (S)-species synthesis, it was simple to adjust the reaction temperature accordingly to differentiate between relative rates in order to obtain a product of a specific configuration. Graphical abstract ᅟ.