Aldo Marino

Solid-phase extraction followed by high-performance liquid chromatography-ionspray interface-mass spectrometry for monitoring of herbicides in environmental water.

In this work we developed a sensitive and specific multiresidue method, based on reversed-phase liquid chromatography-mass spectrometry, with an ionspray interface (LC-ISI-MS), for determining 52 of most representative compounds of herbicides in water samples. The procedure used involved passing 0.5 l of surface water, 2 l of ground water and 4 l of drinking water samples, respectively, through a 0.5 g graphitized carbon black (GCB) extraction cartridge. Base-neutral and acid herbicides were differential eluted from GCB cartridge and follow analyzed by HPLC-ISI-MS apparatus. A conventional 4.6-mm-ID reversed-phase LC C18 column, operating with a mobile phase flow-rate of 1 ml/min, was used to chromatograph the analytes. A flow of 100 microl/min of the column effluent was diverted to the ISI source. The study demonstrates the sensitivity of the technique, with detection limit under 10 ng/l in drinking water samples. Performance data for the method such as recovery and precision are also reported.

Liquid chromatography tandem mass spectrometry applied to the analysis of natural and synthetic steroids in environmental waters

A multiresidue analytical method for the determination of the most common and biologically active natural and synthetic steroids (four estrogens: estriol, 17β-estradiol, 17α-ethynylestradiol, estrone; one progestagen: progesterone and six androgens: trenbolone, boldenone, nandrolone, testosterone, 17α-methyltestosterone, stanozolol) in environmental waters was developed. The analytes were isolated from water samples by solid phase extraction (SPE) utilizing a graphitized carbon black adsorbent (Carbograph-1). The final samples were analyzed by reversed-phase high performance liquid chromatography with tandem mass spectrometry using atmospheric pressure chemical ionization (LC-APCI-MS-MS). Ionization was performed in a heated nebulizer (HN) interface operating in the positive ion mode. The protonated ions [M+H]+ and the dehydrated ions [M+H-H2O]+ (for estriol, 17α-estradiol, 17β-estradiol, and 17α-ethynylestradiol) were used as precursor ion for collision-induced dissociation (CID), and two diagnostic product ions for each analyte were identified for the unambiguous steroid confirmation by multiple reaction monitoring (MRM) mode. Method performance, for this analytical procedure, was validated by analyzing groundwater and river water samples fortified at level of 20 ng/L. The average recovery for each analyte exceeded 82%. Good method precision was demonstrated with percent relative standard deviation of less than 7.2% for all analytes.

General and selective isolation procedure for high-performance liquid chromatographic determination of anabolic steroids in tissues

A multi-residue method has been developed for the determination of anabolic steroids in animal tissue. The analytes are extracted from tissue with methanol and the extract is subjected to two solid-phase extractions, one using a non-specific adsorbing material, such as graphitized carbon black (Carbopack B), and the other Amberlite CG-400 I in the OH form. This procedure allowed the neutral anabolics (testosterone, trenbolone and progesterone) to be isolated and separated from the acidic type (phenolic group), such as diethylstilbestrol, oestradiol, zeranol/zearalenone and their respective metabolites. The determination was effected using high-performance liquid chromatography with different detectors (ultraviolet, fluorimetric and electrochemical). Several analytical parameters were studied: chromatographic conditions, recoveries, evaporation step, solvent flow-rate, cartridges reusability, interference of plastic cartridges. For all the anabolics investigated the recoveries were greater than 83.6%.

Determination of aryloxyphenoxypropionic acid herbicides in water using different solid-phase extraction procedures and liquid chromatography–diode array detection

For isolation and trace enrichment of aryloxyphenoxypropionic acid (ArPP) herbicides from drinking, spring, and ground water a sensitive, robust method is presented. A 1-2 1 volume of aqueous samples was passed through a disposable solid-phase extraction cartridge, packed with 500 mg of Carbograph-1 at a flow-rate of 100 ml/min. After washing, ArPPs are selectively eluted with 8 ml of dichloromethane-methanol (80:20, v/v) with 50 mmol/1 formic acid and evaporated to dryness. The mixture was reconstituted with 250 microliters of water-acetonitrile (75:25; v/v) acidified with 0.1% trifluoroacetic acid and 100 microliters was injected into the high-performance liquid chromatography system. The ArPPs were separated via a binary gradient of water and a mixture of methanol-acetonitrile. Detection and confirmation were performed by diode array detection. Recovery of the six acid herbicides ranged between 90% and 98%. The limits of detection of ArPPs were 7-20 ng/l for drinking water and 16-36 ng/l for spring water. In terms of recovery and selectivity the effectiveness of Carbograph-1 cartridges was compared with that of LiChrolut-EN cartridges and polystyrene-divinylbenzene Empore disks. Relevant parameters such as pH and flow-rate for solid-phase extraction with divinylbenzene resins were optimized.

Simultaneous determination of base/neutral and acid herbicides in natural water at the part per trillion level

SummaryA new method for the simultaneous identification and quantification of base/neutral and acidic pesticides at a low nanogram per liter concentration level in natural waters is presented. The method includes enrichment of the compounds by solid phase extraction on graphitized carbon black, followed by sequential elution of the base/neutral and acidic pesticides. Identification and quantification of the compounds is performed with HPLC-ESI-MS. This procedure involves passing 1 L of ground water and 2 L of drinking water samples through a 0.5 g graphitized carbon black (GCB) extraction cartridge. A conventional 4.6-mm-i.d. reversed phase LC C-18 operating with a 1 mL min−1 flow of the mobile phase was used to chromatograph the analytes. A flow of 100 μL min−1 of the column effluent was diverted to the ESI source. The ESI source was operated in positive ion mode for base/neutral pesticides and in negative-ion mode for acid pesticides. For the analyte considered, the response of the mass detector was linearly related to the amount of the analytes injected between 5 and 250 ng. In all cases, recoveries of the analytes were better than 90%. The limit of detection (signal-to-noise ratio=3) of the method for the pesticides considered in drinking water samples was estimated to be about 3–10 ng L−1.

Determination of organophosphorus pesticides and metabolites in crops by solid-phase extraction followed by liquid chromatography/diode array detection

SummaryA multiresidue method for the analysis of 28 common organophosphorus pesticides and 3 of their main metabolites (paraoxon-ethyl, paraoxon-methyl and malaoxon) in a variety of crop samples has been developed. An aliquot of the chopped sample is homogenized with an organic solvent. The efficiency of extraction methods using methanol, acetone and acetonitrile was evaluated. The acetonitrile gives higher recoveries and minimizes co-extractives from the samples matrix.The resulting aqueous acetonitrile extract is filtered and cleaned by solid phase extraction (SPE). For SPE three different types of adsorption materials (Carbograph 1, LiChrobut-EN and Amberchrom CG-161m) were compared. The cleaned-up extract is injected into the LC system.Three different analytical columns were tested in conjunction with two mobile phase compositions of different polarity.The use of LC-DAD techniques allowed the identification of both organophosphorus pesticides and metabolites by means of standard and spectral comparison, respectively.The accuracy of the quantitative determination measured in terms of average percentage recovery of 31 compounds in crop samples was 61–96% with a relative standard deviation of 5–10%.

Instrumental multiparametric study of the maturing of therapeutic muds of some italian spas

Abstract The problem of the maturing of thermal mud has long been a subject of discussion by many workers, without any objective solution being found. The process consists of the interaction between a fluid component (mineral water) and a solid component (virgin mud). Maturing is an extremely complex phenomenon which includes not only processes peculiar to the interaction between these components but also a wide range of biochemical processes related to the growth of algae and the micro-organisms characteristic of thermal mud. These processes are influenced by the ecosystem in which maturing takes place. Maturing involves a complex set of modifications which can be summed up as: (1) modifications related to the virgin mud, (2) appearance of new chemical species or an increase in those already present, and (3) disappearance or decrease in chemical substances already present. In the present paper, maturing has been investigated using thermal analysis, reflectance spectroscopy. X-ray diffraction, gas, liquid and ionic chromatography, atomic absorption and nuclear magnetic resonance. Families of molecules and physico-chemical parameters have been analysed to evaluate modifications as a function of time, with the aim of identifying any trends in such modifications which might lead to equilibrium conditions which could be considered indicative of maturing.

Application of an innovative matrix solid-phase dispersion–solid-phase extraction–liquid chromatography–tandem mass spectrometry analytical methodology to the study of the metabolism of the estrogenic mycotoxin zearalenone in rainbow trout liver and muscular tissue

The metabolic fate of the estrogenic mycotoxin zearalenone in rainbow trout is presently unknown. In this study, the tissue concentration of zearalenone and its principal metabolites (α-zearalenol and β-zearalenol) was determined. A known amount of zearalenone was administered as a single bolus to ten fish, and the biological tissue concentration was determined at various times following administration. The analytes were extracted from liver and muscular tissue using an on-line matrix solid-phase dispersion–solid-phase extraction sample preparation protocol, and their concentration determined by HPLC–Turboionspray–tandem mass spectrometry. The results showed that zearalenone is mainly metabolized into α-zearalenol in both liver and muscular tissues. The maximum concentrations of each analyte found in liver were 76.1, 211.2 and 63.7 ng/g respectively for zearalenone, α-zearalenol and β-zearalenol, while in muscular tissue they were 10.7, 8.2 and 6.5 ng/g. These values were reached after 2 h in liver tissue and 12 h in muscular tissue. Moreover the data obtained showed that the elimination rate in liver is quite fast since 48 h after the exposure less than 7% of the maximum concentration found is still present. In muscular tissue, however, about one-third of the maximum concentration found is still present after 48 h.

HPLC determination of benzydamine and its metabolite N-oxide in plasma following oral administration or topical application in man, using fluorimetric detection

A method for the extraction and quantification of benzydamine and its metabolite N-oxide by liquid chromatography with fluorescence detection in plasma samples is described. This method has adequate sensitivity, specificity and is reproducible. The use of the extraction column allowed a recovery of both benzydamine and its metabolite of over 97% to be obtained. The plasma levels of benzydamine and its metabolite N-oxide were studied after oral administration as sugar-coated tablets or topical application to the vaginal mucosa as a cream to 6 healthy volunteers. After topical application, the plasma concentrations of the unchanged drug and its metabolite are lower than those obtained following oral administration. These data further stress the concept that, whenever possible, topical use should be considered the treatment of choice since, along with a more selective therapy, the incidence of systemic side effects can be considerably reduced.

A thermoanalytical study of dipicolinic acid acting as a terdentate ligand in coordination compounds of divalent metal ions

Abstract The coordination compounds obtained by reaction of hot solutions of dipicolinic acid with the carbonates of the divalent metal ions manganese(II), iron(II), cobalt(II), nickel(II), copper(II) and zinc(II) are studied using TG, DSC and HTRS techniques. For the thermal stability a sequence Mn > Fe > Zn > Co > Ni > Cu may be observed. This series is compared with the similar series obtained with isocinchomeronic acid. The thermal stability is, for each metal of the series, isocinchomeronic > dipicolinic. Thermal stability is discussed in terms of the intermolecular bonds, of the structures and of the stability constants of the complexes examined.