This paper presents an analysis of the physical properties of materials in powder and agglomerate form and their sorption characteristics on the basis of the shape of the water vapour adsorption isotherms and kinetics. The observed changes that led to a decrease in the vapour adsorption ability of the investigated powdered baby foods depended mainly on their milk powder content and to a lesser extent on the structure of the powders. This was related to the process of agglomeration and the type of wetting liquid used in that process. Wet agglomeration of the baby food powders investigated in this study influenced growth of particle size and increased wettability regardless of the type of wetting liquid used and the components of the powders. The agglomerates obtained using 2% lecithin solution or 50% sugar solution as the wetting liquids presented a decrease in their rate of water adsorption compared to the agglomerates obtained using water.

This work describes the electroanalytical determination of pendimethalin herbicide levels in natural waters, river sediment and baby food samples, based on the electro-reduction of herbicide on the hanging mercury drop electrode using square wave voltammetry (SWV). A number of experimental and voltammetric conditions were evaluated and the best responses were achieved in Britton–Robinson buffer solutions at pH 8.0, using a frequency of 500s⁻¹, a scan increment of 10mV and a square wave amplitude of 50mV. Under these conditions, the pendimethalin is reduced in an irreversible process, with two reduction peaks at −0.60V and −0.71V, using a Ag/AgCl reference system. Analytical curves were constructed and the detection limit values were calculated to be 7.79μgL⁻¹ and 4.88μgL⁻¹, for peak 1 and peak 2, respectively. The precision and accuracy were determinate as a function of experimental repeatability and reproducibility, which showed standard relative deviation values that were lower than 2% for both voltammetric peaks. The applicability of the proposed methodology was evaluated in natural water, river sediments and baby food samples. The calculated recovery efficiencies demonstrate that the proposed methodology is suitable for determining any contamination by pendimethalin in these samples. Additionally, adsorption isotherms were used to evaluate information about the behavior of pendimethalin in river sediment samples.

A kinetic spectrophotometric method for determining residues of insecticide diflubenzuron 1(4-chlorphenyl)-3-(2,6-diflubenzoyl)urea (DFB) has been developed and validated. Kinetic method was based on the inhibitory effect of DFB on the oxidation reaction of sulfanilic acid (SA) by hydrogen peroxide in the presence of Co 2+ ions in a phosphate buffer, which was monitored at 370 nm. DFB can be measured in the concentration interval 0.102 – 3.40 μg mL -1 and 3.40 – 23.80 μg mL -1 . The detection and quantification limits of the method were calculated according to the 3σ criteria and found to be 0.077 μg mL -1 and 0.254 μg Ml -1 , respectively. The relative standard deviations for five replicate determinations of 0.102, 1.70 and 3.40 μg mL -1 DFB were 2.08, 1.22 and 1.21 %, respectively, for the first concentration interval, and the recovery percentage values were from 94.12 to 97.35 %. HPLC method was used as a parallel method to verify results of the kinetic method. The kinetic method was successfully applied to determine diflubenzuron concentrations in spiked water and baby food samples after solid phase extraction of the samples. The F and t values at 95% confidence level are lower than the theoretical ones, confirming agreement of the developed and the HPLC method.

A novel solid phase extraction procedure for determination of copper, lead and iron in natural water and food samples has been established in the presented work. 1-Phenylthiosemicarbazide (1-PTSC) as ligand and Dowex Optipore L-493 resin as adsorbent were used in a mini chromatographic column. Various analytical conditions for the quantitative recoveries of analyte ions including pH, amounts of adsorbent, eluent, sample volume, etc. were investigated. The recovery values for analyte ions were higher than 95%. The determination of copper, lead and iron was performed by flame atomic absorption spectrometry. The influences of some alkali, alkali earth and transition metals on the recoveries of analyte ions were investigated. The preconcentration factor was 62.5. The limit of detections of the understudied analytes (k=3, N=21) were 0.64μgL⁻¹ for copper, 0.55μgL⁻¹ for lead and 0.82μgL⁻¹ for iron. The relative standard deviation was found to be lower than 6%. The accuracy of the method was confirmed with certified reference material (GBW 07605 Tea). The method was successively applied for the determination of copper, lead and iron in water and some food samples including cheese, bread, baby food, pekmez, honey, milk and red wine after microwave digestion.

A new, simple, and rapid separation and preconcentration procedure, for determination of Pb(II), Cd(II), Zn(II), and Co(II) ions in environmental real samples, has been developed. The method is based on the combination of coprecipitation of analyte ions by the aid of the Mo(VI)–diethyldithiocarbamate–(Mo(VI)-DDTC) precipitate and flame atomic absorption spectrometric determinations. The effects of experimental conditions like pH of the aqueous solution, amounts of DDTC and Mo(VI), standing time, centrifugation rate and time, sample volume, etc. and also the influences of some foreign ions were investigated in detail on the quantitative recoveries of the analyte ions. The preconcentration factors were found to be 150 for Pb(II), Zn(II) and Co(II), and 200 for Cd(II) ions. The detection limits were in the range of 0.1–2.2 μg L⁻¹ while the relative standard deviations were found to be lower than 5 % for the studied analyte ions. The accuracy of the method was checked by spiked/recovery tests and the analysis of certified reference material (CRM TMDW-500 Drinking Water). The procedure was successfully applied to seawater and stream water as liquid samples and baby food and dried eggplant as solid samples in order to determine the levels of Pb(II), Cd(II), Zn(II), and Co(II) ions.

This study utilized reduced graphene oxide magnetic nanoparticles Fe₃O₄/rGO-MNP to preconcentrate two alkyl phenols, two organochlorine pesticides and one organophosphate pesticide from water and baby food samples for the determination by gas chromatography flame ionization detector (GC-FID). Parameters of the micro-solid phase extraction (μ-SPE) were fully optimized to boost the measurement signals of the analytes. Optimum extraction conditions were applied to aqueous standard solutions to validate the method. The limit of detection ranged between 0.48 and 2.4 μg/L, recording about 60–100 folds enhancement in detection power when compared directly with the detection limits of the instrument before preconcentration. The optimum method was applied to aqueous samples and spiked recovery tests produced satisfactory results. The baby food sample was treated with the QuEChERS standard method before applying the μ-SPE method. Matrix matching was used to overcome matrix interference to obtain approximately 1.0 % recovery results for all analytes spiked at different concentrations.