Claudia Ancillotti

Liquid chromatographic-tandem mass spectrometric method for the simultaneous determination of alkylphenols polyethoxylates, alkylphenoxy carboxylates and alkylphenols in wastewater and surface-water.

Four different pellicular stationary phases (i.e. octadecylsilane, octasilane, Phenyl-Hexyl and pentafluorophenyl) were investigated for the chromatographic resolution of alkylphenols (APs), alkylphenols polyethoxylates (APnEOs) and alkylphenoxy carboxylates (APECs) using mixtures of water and organic solvents (i.e. methanol, acetonitrile and tetrahydrofuran) as eluents, in order to obtain their determination by a single LC-MS/MS run. In fact, alkylphenols and alkylphenoxy carboxylates must be analysed in negative ion mode, whereas alkylphenols polyethoxylates undergo ionisation only in positive ion mode, and therefore, two distinct LC-MS/MS analysis are commonly adopted. The best resolution among the aforementioned target analytes was achieved on the pentafluorophenyl column, eluting with an acidified water-acetonitrile-tetrahydrofuran mixture and using the post column addition of an ammonia solution in methanol for the detection of positively ionisable compounds. Under these optimized chromatographic conditions the investigated compounds were determined via a single chromatographic run, with only one polarity switch, in 15min, achieving the following instrumental detection limits: 600pg for AP1EOs, 0.8-14pg for AP2EOs, 10.4-150pg for APs and 4.4-4.8pg for APECs. The chromatographic method was coupled with solid-phase extraction and clean-up procedures and successfully applied to the analysis of wastewater and surface water samples, highlighting mean concentration ranging from 6ng/L for 4-t-OP1EC to 1434ng/L for 4-NP1121EC, depending on the sample analysed.

Chromium accumulation and changes in plant growth, selected phenolics and sugars of wild type and genetically modified Nicotiana langsdorffii.

Chromium accumulation, dry weight (DW) biomass yield, water content and concentrations of some selected phenolic compounds and carbohydrates were determined in root and shoot of Nicotiana langsdorffii, either wild type (WT) or genetically modified by the insertion of GR and rolC genes, in response to the presence of Cr(VI) in the growth medium. A biomass decrease was observed for WT plants, but not for GR and rolC transformations, in response to Cr(VI) in the growth medium, highlighting a stress situation only in WT line. Shoot chromium concentrations were in all cases about 300 mg kg(-1) DW. In root higher concentrations were found in rolC than in GR and WT (3843, 2600 and 2751 mg kg(-1) DW, respectively). Based on the DW biomass, GR and WT accumulated higher chromium quantities than rolC, both in root (330 and 424 versus 85 μg Cr per plant) and shoot (282 and 275 versus 121 μg Cr per plant). Therefore, GR should be preferred to WT as a promising candidate for chromium phytoremediation. Metabolic shifts of sugars and phenolics were generally observed in response to either gene insertions or exposure to Cr(VI), being the latter more related to the resistance to Cr(VI) than the former.

Applicability of the direct injection liquid chromatographic tandem mass spectrometric analytical approach to the sub-ng L−1 determination of perfluoro-alkyl acids in waste, surface, ground and drinking water samples

The applicability of a direct injection UHPLC-MS/MS method for the analysis of several perfluoroalkyl acids (PFAAs) in a wide range of water matrices was investigated. The method is based on the direct injection of 100µL of centrifuged water sample, without any other sample treatment. Very good method detection limits (0.014-0.44ngL-1) and excellent intra and inter-day precision (RSD% values in the range 1.8-4.4% and 2.7-5.7%, respectively) were achieved, with a total analysis time of 20min per sample. A high number of samples - i.e. 8 drinking waters (DW), 12 ground waters (GW), 13 surface waters (SW), 8 influents and 11 effluents of wastewater treatment plants (WWTPIN and WWTPOUT) were processed and the extent of matrix effect (ME) was calculated, highlighting the strong prevalence of |ME| < 20%. The occurrence of |ME| > 50% was occasionally observed only for perfluorooctanesulphonic and perfluorodecanoic acids. Linear discriminant analysis highlighted the great contribution of the sample origin (i.e. DW, GW, SW, WWTPIN and WWTPOUT) to the ME. Partial least square regression (PLS) and leave-one-out cross-validation were performed in order to interpret and predict the signal suppression or enhancement phenomena as a function of physicochemical parameters of water samples (i.e. conductivity, hardness and chemical oxygen demand) and background chromatographic area. The PLS approach resulted only in an approximate screening, due to the low prediction power of the PLS models. However, for most analytes in most samples, the fitted and cross-validated values were such as to correctly distinguish between | ME | higher than 20% or below this limit. PFAAs in the aforementioned water samples were quantified by means of the standard addition method, highlighting their occurrence mainly in WWTP influents and effluents, at concentrations as high as one hundred of µgL-1.

Determination of Rare Earth Elements in multi-year high-resolution Arctic aerosol record by double focusing Inductively Coupled Plasma Mass Spectrometry with desolvation nebulizer inlet system

An inductively coupled plasma sector field mass spectrometer (ICP-SFMS) was used to develop an analytical method for the fast determination of Na, Al, Sc, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Y, Mo, Cd, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Pb in Arctic size-segregated aerosol samples (PM10), after microwave acidic digestion. The ICP-SFMS was coupled with a microflow nebulizer and a desolvation system for the sample introduction, which reduced the isobaric interferences due to oxides and the required volume of sample solutions, compared to the usual nebulization chamber methods. With its very low limit of detection, and taking into account the level of blanks, this method allowed the quantification of many metals in very low concentration. Particular attention was given to Rare Earth Elements (REEs - La to Lu). The efficiency in the extraction of REEs was proved to be acceptable, with recoveries over 83% obtained with a Certified Reference Material (AMiS 0356). The analytical method was then applied to particulate matter samples, collected at ground level in Ny Ålesund (Svalbard Islands, Norway), during spring and summer, from 2010 to 2015, with daily resolution and using a low-volume device. Thus, for the first time, a large atmospheric concentrations dataset of metals in Arctic particulate matter at high temporal resolution is presented. On the basis of differences in LREE/HREE ratio and Ce and Eu anomalies in spring and summer samples, basic information to distinguish local and long-range transported dust were achieved.

Determination of phthalate diesters and monoesters in human milk and infant formula by fat extraction, size-exclusion chromatography clean-up and gas chromatography-mass spectrometry detection

Graphical abstract Figure. No Caption available. HighlightsA method for the analysis of phthalate diesters and monoesters in milk is proposed.Phthalate monoesters and diesters were analysed in breastmilk and infant formulas.Target analytes were found to be present in all the investigated samples.Phthalate contamination was higher in infant formula than in breast milk.Daily intake of phthalates was lower than MADI established by EU‐CSTEE and EU‐SCF. ABSTRACT A sensitive and reliable analytical method was developed for the simultaneous determination of five phthalate diesters and corresponding monoesters in human milk samples and infant formulas. The method involved a liquid–liquid extraction with a CH2Cl2/CH3OH/NaCl 30% 2/1/0.5 (v/v/v) mixture, the clean‐up of the extract by size‐exclusion chromatography (swelling and elution solvent: cyclohexane/ethyl acetate 9/1 v/v), the derivatization of monoesters by trimethylsilyl‐diazomethane and instrumental analysis by gas chromatography coupled with mass spectrometry. Recovery was in the range of 83–115% and precision was found between 9% and 21%. For phthalate diesters, method detection limits (MDLs) ranged from hundreds of ng/kg to 4.2 &mgr;g/kg on a fresh weight milk (f.w.) basis, depending on blank contribution evaluated in matrix. Lower MDLs (0.03‐0.8 &mgr;g/kg f.w.) were achieved for corresponding monoesters. The proposed method was applied to the determination of target compounds in nine human milk samples and four infant formulas, confirming their presence in all samples. However, a generally higher contamination was assessed in artificial milk than in breast milk samples.

Quality by design compliant strategy for the development of a liquid chromatography–tandem mass spectrometry method for the determination of selected polyphenols in Diospyros kaki

Diospyros kaki fruits possess great beneficial properties for human health due to their strong antioxidant and antiradical activities related to the high level of bioactive compounds and particularly polyphenols. In this paper a rapid and efficient liquid chromatography-tandem mass spectrometry method for the determination of 38 polyphenolic compounds in Diospyros kaki flesh was developed. The optimization of the chromatographic method was performed applying a Quality by Design approach, which is unexplored in the field of food analysis. The Critical Method Attributes (CMAs) were the critical resolutions of some isobaric compounds and analysis time. The Critical Methods Parameters (CMPs) were related to the characteristics of both the mobile phase and the column: flow rate, temperature, starting organic phase concentration of the mobile phase, formic acid percentage in the eluents, type of organic solvent in the mobile phase and gradient of organic eluents. The effects of the CMPs on the CMAs were evaluated by experimental design, at first carrying out a screening phase by an asymmetric screening matrix and then applying Response Surface Methodology by a Doehlert Design. The quadratic polynomial models postulated to link the CMAs to CMPs were calculated and the Method Operable Design Region was identified with the aid of Monte Carlo simulations as the multidimensional combination of the CMPs that satisfied the requirements for the CMAs with a probability ≥90%. The developed method was applied to real samples obtained by the extraction of Diospyros kaki flesh from two different cultivars (Rojo Brillante and Kaki Tipo), making it possible to obtain extensive information on their polyphenolic profiles.

Genetic diversity and changes in phenolic contents and antiradical activity of Vaccinium myrtillus berries from its southernmost growing area in Italy

In this study, we evaluated by the RAPD technique the genetic diversity of 42 individual Vaccinium myrtillus L. plant samples, collected from different locations of Tuscan Apennines (Italy), which represent the southernmost growing latitude of this plant. Total polyphenols, total anthocyanins and radical scavenging activity were also determined in two successive harvesting years on bilberry samples obtained from the same individuals characterized by molecular analysis. The RAPD analysis indicated a highly prevalent gamic propagation of bilberry in the investigated area, and, in accordance with genetic findings elsewhere reported for populations of Central and Northern Europe, suggested the presence, from North-to-South Europe, of a clonal-to-gamic genetic gradient of the propagation strategy. In the context of a quite homogeneous panorama of biochemical data, significant variations were occasionally evidenced by comparing closely-located individuals. We tentatively attributed such variations mainly to genetics, due to the very close location of biomes exhibiting different biochemical attributes. However, molecular clustering by RAPD did not show any relationship with biochemical diversity. Strong variations of climatic conditions were probable responsible of the remarkable variability of the investigated biochemical parameters in the two harvesting years.