Nadia Ghedini

Organic anions in damage layers on monuments and buildings

Abstract This article is focused on small (C1–C2) organic anions present in the damage layers on historic monuments and buildings. Formate, acetate and oxalate are consistently found in black crusts, where atmospheric deposition accumulates along with the products of the chemical transformation of stone and mortars. While sulphation processes affecting building materials have been extensively studied, the importance of carbon compounds in black crusts is only recently being realised. Recent data show carbon to be the second most important airborne element after sulphur in damage layers on building exteriors. Total carbon is composed of carbonate-, organic-, and elemental carbon. The organic fraction includes formate, acetate and oxalate; these are always detected in black crusts. Their origin, role and measurement in the atmosphere and in the museum environment have been the subject of many studies, but little has been reported concerning their presence in building exterior damage layers. This paper presents data on these anions in damage layers on stones and mortars sampled on monuments and buildings at different urban, suburban and rural European sites. Oxalate encountered in black crusts likely originates from the metabolism of micro-organisms and protective treatments on surfaces. Primary and secondary atmospheric pollutants are likely the main sources of formate and acetate anions.

Liquid chromatographic determination of oxcarbazepine and its metabolites in plasma of epileptic patients after solid-phase extraction.

A method based on high-performance liquid chromatography with UV detection in combination with solid-phase extraction for sample pretreatment has been developed for the simultaneous analysis of the antiepileptic drug oxcarbazepine and its main metabolites in human plasma. The extraction of the analytes from plasma samples was carried out by means of a selective solid-phase extraction procedure using hydrophilic-lipophilic balance cartridges. The separation was obtained on a reversed-phase column (C(18), 150x4.6 mm I.D., 5 micrometer) using a phosphate buffer-acetonitrile-methanol-triethylamine mixture (final apparent pH* 3.5) as the mobile phase. Under these chromatographic conditions, oxcarbazepine and its metabolites 10,11-dihydro-10-hydroxycarbamazepine, 10,11-dihydro-10,11-dihydroxycarbamazepine and the internal standard are baseline separated in less than 9 min. The extraction yield values were >94% for all analytes and the precision, expressed by the RSD%, was in the low percentage range. For the entire method, including sample pre-treatment and HPLC determination, the linearity of the calibration lines, expressed by the linear correlation coefficient, was better than 0.995; the limit of quantitation was 15 ng ml(-1). The method was applied to plasma samples from patients undergoing chronic treatment with oxcarbazepine, both in monotherapy and in polytherapy. Based on the analytical parameters precision, accuracy, limit of quantitation and analysis time the method is suitable for routine application in therapeutic drug monitoring.

Determination of elemental and organic carbon on damaged stone monuments

An analytical methodology was developed for the discrimination and evaluation of the different types of carbon matter, particularly carbonate, elemental and organic carbon, present on monuments and historical buildings, due to interaction between materials and atmospheric pollution. With this aim samples of black patinas were analysed by a procedure consisting of three different steps. Total, noncarbonate and elemental carbon were measured by combustion-chromatographic CO2 determination: Ct was obtained by burning the bulk samples (step 1), while Cnc and Ce were quantified after elimination of Cc with acid treatment (step 2) and elimination of Co by means of alternate attacks, followed by centrifugation, with concentrate acid and base solutions at high temperature and pressure (step 3); the carbonate carbon and the organic carbon were then calculated. Furthermore, for a complete sample characterization, oxalate, acetate, formate and the main anion contents were detected by ion chromatography. The methodology was also tested on standard samples containing the same carbon species as the black crusts. The results obtained indicate that this approach satisfactorily distinguishes between elemental and organic carbon and allows reliable elemental carbon determination at the ppm level in black damage crust samples from historic monuments and buildings.

Black crusts on ancient mortars

Samples of mortar damage layers found on ancient masonry have been analysed. The paper presents the characterisation of the black crusts, which are the accumulation areas of material damage and atmospheric deposition, and includes a complete identification of the sulphur, nitrogen and carbon compounds. The presence of anthropic aerosol and its role in the process of damage is evidenced.

Determination of olanzapine and desmethylolanzapine in the plasma of schizophrenic patients by means of an improved HPLC method with amperometric detection

SummaryAn improved HPLC method with electrochemical detection has been developed for the determination of olanzapine and its main metabolite, desmethylolanzapine, in human plasma. Chromatographic separation and analysis were performed on a C8 reversed-phase column with a mixture of methanol, acetonitrile, and pH 3.7 phosphate buffer as mobile phase; 2-methylolanzapine was used as internal standard. Careful pretreatment of the plasma samples was implemented by means of solid phase extraction (SPE).Response was linearly dependent on concentration and precision was satisfactory over the concentration range 0.5–75.0 ng mL−1 for both analytes. The limit of detection was 0.2 ng mL−1 for both analytes. Application to plasma samples of patients treated with Zyprexa tablets gave good results. Because of its sensitivity and selectivity, and the need for small plasma samples, this method seems to be a useful tool for clinical monitoring.

Assessment of air pollutant sources in the deposit on monuments by multivariate analysis.

A proper recognition of the pollutant sources in atmospheric deposit is a key problem for any action aiming at reducing their emission, being this an important issue with implications both on human health safeguard and on the cultural heritage conservation in urban sites. This work presents the results of a statistical approach application for the identification of pollutant sources in deposits and damage layers on monuments located in different European sites: Santa Maria del Fiore, Florence (Italy), Cologne Cathedral, Cologne (Germany), Ancient ramparts, Salè (Morocco), National Museum, Cracow (Poland) and National Gallery, Oslo (Norway). For this aim, the surface damage layers on monuments and historical buildings of the selected sites were collected and analyzed, in terms of ionic and elemental composition, through application of ion chromatography and induced coupled plasma-optical emission spectroscopy. The achieved results were processed by multivariate analyses such as correlation matrix and principal component analysis in order to identify the possible origin of pollutants affecting the state of conservation of the monuments. This allowed us to assume that in all case studies the traffic emission is the main pollutant source. In the case of Ancient ramparts, Salè (Morocco), and National Gallery, Oslo (Norway), the surfaces are also under influence of marine aerosols. Moreover, concerning the Cologne Cathedral, the strong impact of the pollutants emitted by railway station was also revealed.

Thermal analysis in cultural heritage safeguard: an application

Damage layer formation on buildings is due to the deposition of atmospheric pollutants and their interaction with the underlying materials. The composition of black crusts is therefore closely related to the characteristics and levels of pollution in the surrounding environment. Thus, the study of its constituents is of fundamental importance in planning strategies for the protection and conservation of monuments and historic buildings. Damage layers have been shown to be primarily composed of carbonaceous particles embedded in gypsum, pointing to the overwhelming role of combustion-derived air pollution in their formation. The identification and evaluation of elemental carbon and other carbon species constituting the non-carbonate fraction of total carbon is required in investigating the damage on historic buildings in urban areas. The removal of organic carbon is a critical step in the analytical methodologies used for the measurement of elemental carbon. The paper describes a study performed on black crust samples from historic buildings of two Italian towns, on which the carbon compound discrimination was achieved by applying an analytical methodology based on thermal analysis.

A fast and feasible microextraction by packed sorbent (MEPS) procedure for HPLC analysis of the atypical antipsychotic ziprasidone in human plasma

An original high-performance liquid chromatographic method coupled to microextraction by packed sorbent (MEPS) was developed for the therapeutic drug monitoring (TDM) of psychiatric patients treated with the recent atypical antipsychotic ziprasidone. The chromatographic separation was achieved on a RP C18 column, using an isocratic mobile phase and setting the wavelength at 320nm. The analyte was extracted from human plasma by means of a fast and feasible innovative MEPS procedure, optimised on C2 sorbent and requiring only 100μL of biological sample. A second pre-treatment procedure, based on solid phase extraction (SPE), has been also developed for comparison. The availability of different pre-treatment procedures allows the choice of the one best suiting the specific clinical, economic and scientific needs. The extraction yield values were always higher than 90% and sensitivity was also good, with a limit of quantitation (LOQ) of 1ng/mL. The method was successfully applied to plasma samples from ten subjects undergoing therapy with ziprasidone, thus confirming its suitability for the TDM of psychiatric patients, in order to personalise their pharmacological treatments.

Multi-matrix assay of cortisol, cortisone and corticosterone using a combined MEPS-HPLC procedure

The development and validation of a bioanalytical assay for the simultaneous determination of cortisol, cortisone and corticosterone levels in several matrices, such as saliva, plasma, blood and urine samples have been described. The method is based on a rapid test which combines a microextraction by packed sorbent procedure and liquid chromatography-diode array technique. Chromatographic separation of the analytes (cortisol, cortisone and corticosterone) and the internal standard (methylprednisolone) was achieved in less than 10min on a reversed-phase pentafluorophenyl column using a mobile phase composed of phosphate buffer and acetonitrile. The assay was performed after an innovative microextraction procedure by means of C8 sorbent which guaranteed good clean-up of the matrices and satisfactory extraction yield of the analytes. Moreover, the method gave linear results over a range of 5-100ngmL(-1) and showed good selectivity and precision. This method was successfully applied for quantifying corticosteroids in specific matrices derived from some healthy volunteers in comparison to two socially diversified groups, namely former heroin addicts undergoing opioid replacement therapy and poly-drug abusers.

Evaluation of atmospheric deposition on historic buildings by combined thermal analysis and combustion techniques

Abstract Black crusts collected from monuments and historic buildings were analyzed. The analytical methodology adopted involved a preliminary characterization of the samples by means of X-ray diffraction (XRD), optical microscopy (OM) and scanning electron microscopy (SEM-EDAX). The anions present were quantified using ion chromatography (IC). Differential thermal analysis (DTA) and thermogravimetric analysis (TGA), combined with combustion techniques, allowed the quantification of the products of degradation and atmospheric deposition. In addition, the carbon of atmospheric origin was identified and quantified in its carbonate, non-carbonate, elemental and organic fractions.