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Fra le manifestazioni cliniche del COVID, il coinvolgimento dell’apparato cardiovascolare è ad oggi un’evidenza accertata. Sono stati descritti sintomi cardiologici anche ben oltre la fase acuta e la dimissione ospedaliera, con quadri clinici variabili che possono perdurare per mesi. Al fine di valutare la frequenza e il tipo di danno cardiovascolare in pazienti con pregresso COVID-19, anche asintomatico e paucisintomatico, A.R.C.A. (Associazioni Regionali Cardiologi Ambulatoriali), ha progettato e diffuso tra i suoi associati un registro ad hoc. Nel presente articolo è discusso il razionale ed illustrato il progetto dello studio.

A sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous determination of 13 steroidal anti-inflammatory drugs in bovine milk is presented. Due to their weakly acid nature, analytes were separated by ion suppression reversed phase chromatography and detected in positive-ion mode by a high flow electrospray source. Dexamethasone-d4 was used as internal standard. The sample preparation was simple and reliable; it included acidic deproteinization of milk followed by sample enrichment and clean-up, utilizing a C18 solid phase extraction cartridge. Recoveries exceeded 70% with an intra-day precision not larger than 12%. The efficiency of the sample clean-up and internal standardization rendered negligible the matrix effect, estimated by comparing standard and matrix-matched calibration curves. A small-scale reconnaissance was carried out on several raw and whole fresh milk samples. A large number of analyzed samples showed a chromatographic peak, in the retention time window of cortisol, at levels included between its decision limit (CCalpha) and detection capability (CCbeta). As a result of a heat-induced transformation, an isomeric product of triamcinolone was observed during the extract evaporation. Since this rearrangement might occur during the milk pasteurization process, LC-MS/MS and (1)H-NMR investigations were performed out to conclusively differentiate the two isomers. One- and two-dimensional proton NMR spectra were able to identify the transformation product as 9a-fluoro-11b,16a-trihydroxy-17b-hydroxymethyl-D-homoandrosta-1,4-diene-3,17a-dione.

A simple and rapid method able to determine residues of seven quinolone antibacterials in whole eggs is presented here. This method is based on the matrix solid-phase dispersion technique with hot water as extractant followed by liquid chromatography–tandem mass spectrometry. After depositing 1.5 g of an egg sample containing the analytes and the analyte surrogate (norfloxacin) on sand (crystobalite), this material was packed into an extraction cell. Quinolones were extracted by flowing 6 mL of water acidified with 50 mmol/L formic acid through the cell heated at 100 °C. After pH adjustment and filtration of the extract, 100 μL of it was injected into the LC column. MS data acquisition was performed in the multiple reaction monitoring mode, selecting two precursor ion to product ion transitions for each target compound. Hot water appeared an efficient extracting medium, since absolute recoveries of the analyte in egg at the level of 20 ng/g were 89–103%. Estimated limits of quantification (S/N = 10) were 0.2–0.6 ng/g. Based on the EU Commission Decision 2002/657/EC, the method was validated in terms of ruggedness, specificity, linearity, within-laboratory reproducibility, decision limit (CC α and detection capability (CC β ). Depending on the particular analyte, CC α s ranged between 0.41 and 2.6 ng/g, while CC β s were 0.64–3.7 ng/g. The method was linear in the 3–30 ng/g range, with typical R 2 values higher than 0.97. The within-laboratory reproducibility ( n = 21) at 6 ng/g level was in the 9.0–12% range. After validation, a depletion study of enrofloxacin and one of its metabolites, i.e. ciprofloxacin, in eggs was conducted.

A rapid, simple and sensitive method based on liquid chromatography/tandem mass spectrometry (LC/MS/MS) with an electrospray ionization (ESI) source for the simultaneous analysis of fourteen water-soluble vitamins (B1, B2, two B3 vitamers, B5, five B6 vitamers, B8, B9, B12 and C) in various food matrices, i.e. maize flour, green and golden kiwi and tomato pulp, is presented here. Analytes were separated by ion-suppression reversed-phase liquid chromatography in less than 10 min and detected in positive ion mode. Sensitivity and specificity of this method allowed two important results to be achieved: (i) limits of detection of the analytes at ng g(-1) levels (except for vitamin C); (ii) development of a rapid sample treatment that minimizes analyte exposition to light, air and heat, eliminating any step of extract concentration. Analyte recovery depended on the type of matrix. In particular, recovery of the analytes in maize flour was > or =70%, with the exception of vitamin C, pyridoxal-5'-phosphate and vitamin B9 (ca 40%); with tomato pulp, recovery was > or =64%, except for vitamin C (41%); with kiwi, recovery was > or =73%, except for nicotinamide (ca. 30%).

Two new methods of analysis, based on liquid chromatography–tandem mass spectrometry, for simultaneous determination of trichothecenes A, B, and D in maize flour and oil have been developed and validated in accordance with European Commission decision 2002/657/EC (recovery, CCα, CCβ, and precision). The trichothecenes were extracted from maize flour by matrix solid-phase dispersion, with recoveries ≥79%, and from maize oil by liquid–liquid extraction, with recoveries ≥78%. Limits of quantitation ranged between 0.03 and 50 μg kg−1, depending on the electrospray response to each analyte and on the matrix. Monitoring of flour and oil samples with this HPLC–MS–MS method revealed the presence of deoxynivalenol, T-2 toxin, and diacetoxyscirpenol at very low concentrations.

The aim of this research was to verify the possibility of identifying and classifying maize seeds obtained from transgenic plants, in different classes according to the modification, on the basis of the concerted variation in metabolite levels detected by NMR spectra. It was possible to recognise the discriminant metabolites of transgenic samples as well as to classify non-a priori defined samples of maize. It is important to underline that the obtained results are useful to point out the metabolic consequences of a specific genic modification on a plant, without using a targeted analysis of the different metabolites, in fact it was possible to classify the seeds also without the complete assignment of the spectra. The analysis was performed by applying multivariate techniques (principal component analysis and partial least squares-discriminant analysis) to NMR data.

A reliable, sensitive and selective liquid chromatography/tandem mass spectrometry (LC/MS/MS) method has been developed to determine four trichothecene mycotoxins (nivalenol, deoxynivalenol, fusarenon X and 3-acetyldeoxynivalenol) in maize. Sample preparation was performed by extracting the analytes with a mixture of acetonitrile and water, followed by a solid-phase extraction with Carbograph-4 cartridges as the purification step. For the LC/MS/MS analysis two interfacing systems, Turbo IonSpray (TISP) and atmospheric pressure chemical ionization (APCI), were compared in both negative and positive ion modes. LC and MS parameters were optimized to achieve better results and sensitivity. The effect of mobile phase modifiers such as ammonium acetate and formic acid on the ionization yield was also evaluated. The best results were obtained using the electrospray ionization (ESI) interface in negative ion mode and the multiple reaction monitoring mode (MRM) for the quantitation. The detection limits ranged between 10 ng/g for fusarenon X and 1.5 ng/g for deoxynivalenol. A linear working range was achieved with a standard deviation between 3 and 10% and recovery rates from the maize samples above 81%. The procedure was applied to the analysis of a set of maize samples collected from farms located in different areas of northern and central Italy. The investigated samples turned out to be contaminated primarily with deoxynivalenol and, to a minor extent, with its derivatives.

Molecularly imprinted polymers (MIPs) for 17β-estradiol were prepared following a multistep procedure including swelling and polymerization using polystyrene seeds, 4-vinylpyridine as the functional monomer and ethylene glycol dimethacrylate (EDMA) as crosslinker. Dibutylphthalate (DBF) and toluene were employed as swelling and porogenic compounds. All the samples showed a mono- modal and very narrow diameter distribution with mean diameter values in the 2.0-4.7 μm range. The microspheres prepared in the presence of the template molecule present surface available vinyl pyridine unit content higher than those prepared without the template. The amphiphilic nature of the pre-polymerization complex between vinyl pyridine and 17β-estradiol can be claimed to be responsible for a preferential location of the vinyl pyridine units at the microsphere surface. The ability of molecular recognition depends on the accessibility of interaction sites located on surface of polymeric particles that increases when the ratios EDMA/polystyrene seed and DBF/polystyrene seed increase.

Sewage treatment plant (STP) effluents with primarily domestic inputs are strongly suspected to be an important source of natural and synthetic estrogens contaminating the aquatic environment. Even a few ng/L of some of these substances can provoke reproductive disturbances in riverine fish. The main purpose of this investigation has been that of ascertaining whether activated sludge STPs (ASSTPs) are able to produce significant amounts of free estrogens. For this purpose, we have monitored monthly estriol (E3), estradiol (E2), estrone (E1) and ethinylestradiol (EE2) in influents and effluents of six Roman ASSTPs for five months. To do this, we have developed an original analytical method involving analyte extraction with a Carbograph 4 cartridge and LC coupled with negative turbo ion spray tandem mass spectrometry in the selected reaction monitoring mode. Analyte recovery ranged between 86 and 91%, and limits of quantification were below 1 ng/L. Over five months, inlet concentrations of E3, E2, E1 and EE...

A post-emergence (POE) herbicide can be defined as a foliage-applied product used to control weeds that have emerged in competition with the developing crop. We developed a sensitive and specific multiresidue method, based on reversed-phase liquid chromatography/mass spectrometry, with an electrospray interface (LC/ESI/MS), for determining 15 of most representative compounds of a new class of POE herbicides in water samples. The procedure used involved passing 2 L of groundwater and 4 L of drinking water samples, respectively, through a 0.5 g graphitized carbon black (GCB) extraction cartridge. A conventional 4.6 mm i.d. reversed-phase LC C-18 column, operating with a mobile phase flow rate of 1 mL/min, was used to chromatograph the analytes. A flow of 200 μL/min of the column effluent was diverted to the ESI source. The study demonstrates the sensitivity of the technique, with detection limit under 5 ng/L in drinking water samples. Performance data for the method such as recovery and precision are also r...

An evaluation was made of the feasibility of using reversed-phase liquid chromatography-mass spectrometry with an electrospray interface (LC-ESI-MS) to measure traces of imidazolinone herbicides in different natural water samples. The imidazolinones are a significant new class of low-use-rate, reduced-environmental-risk herbicides for the protection of a wide variety of agricultural commodities. The procedure used involved passing 0.5, 1, 2 1 of river, ground and drinking water samples, respectively, through a 0.5 g graphitized carbon black (GCB) extraction cartridge. Analytes were eluted from the GCB surface by 8 ml of a methylene chloride-methanol (80:20, v/v) solution acidified with formic acid, 25 mM. Recovery was higher than 89% irrespective of the aqueous matrix in which the analytes were dissolved. A conventional 4.6 mm I.D. 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 50 microliters/min of the column effluent was diverted to the ESI source. The effects of acid concentration on ESI-MS detector response in the mobile phase were investigated. The effects on the production of diagnostic fragments produced by varying the orifice plate voltage and the response of the MS detector were also evaluated. For the analyte considered, the response of the mass detector was linearly related to the amount of analyte injected between 1 and 50 ng. 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 2-5 ng/l.

A method based on liquid chromatography with atmospheric pressure positive-ion chemical ionization detection in the presence of ammonium acetate and formic acid for the determination of ticlopidine in human serum and plaque has been developed. The drug was extracted from the biological matrices using a single solid-phase C-18 cartridge. The protonated molecule with substantial fragmentation was obtained by using this ionization technique. The ion signals in different solvents were evaluated. The chromatographic run time was about 10 min and the method had sufficient sensitivity, precision, accuracy and selectivity for the analysis of clinical sample containing ticlopidine at concentrations down to 1 ng ml−1 for serum samples and 1 ng g−1 for plaque samples. The limits of detection (signal : noise=3) were 300 pg ml−1 and 330 pg g−1, respectively.

A confirmatory method for the determination of illicit drugs based on micro-solid phase extraction with modified tips, made of a functionalized fiberglass with apolar chains of octadecylsilane into monolithic structure, has been developed in this study. Drugs belonging to different chemical classes, such as amphetamine, methamphetamine, methylenedioxyamphetamine, methylenedioxyethylamphetamine, methylenedioxymethylamphetamine, cocaine, benzoylecgonine, ketamine, mescaline, phencyclidine and psilocybine were analyzed. The quantitation was performed by liquid chromatography–tandem mass spectrometry and the analytes were detected in positive ionization by means of an electrospray source. The limits of quantification ranged between 0.3 ng mL −1 for cocaine and 4.9 ng mL −1 for psilocybine, with coefficients of determination ( r 2 ) >0.99 for all the analytes as recommended in the guidelines of Society of Forensic Toxicologists-American Association Forensic Sciences.

An analytical procedure for the simultaneous determination in human plasma and oral fluids of several illicit drugs belonging to different chemical and toxicological classes is presented. Amphetamine, methamphetamine, morphine, 6-monoacetylmorphine, methylenedioxyamphetamine, methylenedioxyethylamphetamine, methylenedioxymethamphetamine, cocaine, benzoylecgonine, tetrahydrocannabinol, carboxytetrahydrocannabinol, ketamine, and phencyclidine have been quantified in real samples using a very rapid sample treatment, basically a protein precipitation. The quantitative analysis was performed by liquid chromatography-tandem mass spectrometry and has been fully validated. All the analytes were detected in positive ionization mode using a TurboIonSpray source, except carboxytetrahydrocannabinol, which was detected in negative ionization mode. The use of a diverter valve between the column and the mass spectrometer allows the preservation of the ion source performances for high-throughput analysis.

A rapid, simple and sensitive method based on liquid chromatography/tandem mass spectrometry (LC/MS/MS) with an electrospray ionization (ESI) source for the simultaneous analysis of fourteen water-soluble vitamins (B1, B2, two B3 vitamers, B5, five B6 vitamers, B8, B9, B12 and C) in various food matrices, i.e. maize flour, green and golden kiwi and tomato pulp, is presented here. Analytes were separated by ion-suppression reversed-phase liquid chromatography in less than 10 min and detected in positive ion mode. Sensitivity and specificity of this method allowed two important results to be achieved: (i) limits of detection of the analytes at ng g(-1) levels (except for vitamin C); (ii) development of a rapid sample treatment that minimizes analyte exposition to light, air and heat, eliminating any step of extract concentration. Analyte recovery depended on the type of matrix. In particular, recovery of the analytes in maize flour wasor =70%, with the exception of vitamin C, pyridoxal-5'-phosphate and vitamin B9 (ca 40%); with tomato pulp, recovery wasor =64%, except for vitamin C (41%); with kiwi, recovery wasor =73%, except for nicotinamide (ca. 30%).

A rapid, specific and sensitive procedure for determining residues of eight widespread used quinolone antimicrobials in bovine milk is presented. The method is based on the matrix solid-phase dispersion technique with hot water as extractant followed by LC/MS/MS. The entire sample treatment did not take more than 40 min. Hot water appeared to be an efficient extracting medium, since absolute recoveries of the analytes in milk were 77–90%. The method proved to be robust as matrix effects did not affect significantly the accuracy of the method, as evidenced by analyzing six different batches of milk. Using norfloxacin as surrogate analyte, the accuracy of the method at three different spike levels of the analytes in milk was 93–110% with RSDs not larger than 10%. On the basis of a S/N of 10, estimated LOQs of this method range from 0.3 to 1.5 ng/ml, well below the tolerance levels of quinolones in milk set by the European Union.

A rapid and sensitive procedure for determining residues of seven quinolone antibacterials in bovine muscle, kidney and liver is presented. The method is based on the matrix solid-phase dispersion (MSPD) technique with hot water as extractant followed by liquid chromatography/single quadrupole mass spectrometry (LC/MS) or triple-quadrupole mass spectrometry (LC/MS/MS). After dispersing tissue samples on hydrazine sulfate treated sand, target compounds were eluted from the MSPD column by passing through it 4 mL of water heated at 100 degrees C. After pH adjustment and filtration, 200 and 5 microL of the aqueous extracts were respectively injected into the LC/MS and LC/MS/MS instruments. With the former instrument, MS data were acquired in the three-ion selected ion monitoring mode, while MS/MS data acquisition was performed in the multi-reaction monitoring mode by selecting two precursor ion to product ion transitions for each target compound. Hot water appeared to be an efficient extracting medium, since absolute recoveries of the analytes were 84-102%. Using norfloxacin (a quinolone not used in veterinary medicine) as surrogate internal standard, the accuracy of the method at three concentration levels equal to 0.5, 1 and 1.5 times the maximum residue limits (MRLs) set by the european union was 88-109% with relative standard deviations (RSDs) not higher than 7%. The use of LC/MS/MS allowed detection and quantification of the analytes in any tissue considered to be performed at concentrations by far lower than half of their MRLs. Vice versa, the single-quadrupole MS arrangement, while succeeding in monitoring quinolones in muscle tissue at the 0.5 MRL level, showed to be not sufficiently selective for unambiguous identification of some quinolones in kidney and liver.

A sensitive, reliable liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for determining some commonly found mycotoxins produced by Fusarium strains in maize was evaluated and applied to field samples. The selected substances were: trichothecenes B (nivalenol, deoxynivalenol, fusarenon X, 3- and 15-acetyldeoxynivalenol) and some macrocyclic lactones (zearalenone, α- and β-zearalenol, zearalanone, α- and β-zearalanol). Analytes were extracted from a 1 g sample by homogenization with acetonitrile/water (75:25, v/v, 25 mL final volume). 5 mL of crude extracts was cleaned-up on Carbograph-4 cartridges. Two fractions were obtained and were analyzed by HPLC-electrospray ionization (ESI) in negative mode. Recoveries for spiked maize samples were in the range 79–106% and method detection limits (MDLs) were ⩽6 ng/g for all compounds, except fusarenon X (12 ng/g). 25 random maize samples were analyzed both by the ELISA-based methods specific for deoxynivalenol and zearalenone and by this method for trichothecenes B and macrocyclic lactones. Results were comparable for zearalenone ( R 2 = 0.982), but disagreed for deoxynivalenol. Finally, a total of 78 freshly harvested maize samples, collected from central and northern Italy during 2002, and divided in two different experiments, were analyzed by the developed method. Data show that there exists a phenomenon of random contamination from the target fusariotoxins just before harvest and an increase of trichothecene B and zearalenone abundance on field crop possibly related to damp climate, temperature range and delayed harvest period. Deoxynivalenol was the most abundant (up to 3430 ng/g) and frequent mycotoxin (40%) detected, followed by acetyldeoxynivalenol. Derivatives of zearalenone were present in traces and β-zearalanol was never found.

The historical development of paper chromatography is reviewed from the work of Runge up to the contribution of Tswett. The type of support, the path of substances and the forces responsible for the phenomenon are discussed in detail.

A very sensitive and specific analytical procedure for determining arylphenoxypropionic herbicides in aqueous environmental samples, using pneumatically assisted electrospray (ESI) liquid chromatography–mass spectrometry (LC–MS) is presented. Arylphenoxypropionic acids are a new class of herbicides used for the selective removal of most grass species from any nongrass crop. These herbicides are commercialized as herbicide esters. It has been shown that the ester derivatives undergo fast hydrolysis in the presence of vegetable tissues and soil bacteria, yielding the corresponding free acid. The analytical procedure involves passing 1 l of surface or 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 C18, operating with a 1 ml/min mobile phase flow-rate, was used for chromatographing the analytes. A flow of 200 μl/min of the column effluent was diverted to the ESI source. The ESI source was operated in positive-ion mode for neutral pesticides and in negative-ion mode for acid pesticides. For ion-signal optimization, the effect of the concentration of the acid in the mobile phase on the response of the ESI–MS detector was investigated. By evaluating the specificity and sensitivity of the method, the effects of varying the orifice plate voltage on the production of the diagnostic fragment and the response of the MS detector were also investigated. For the analyte considered, the response of the mass detector was linearly related to the amount of the analyte injected between 1 and 200 ng. In all cases, recoveries of the analytes were better than 91%. 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.

A solubility and thermoanalytical study of alkali and alkaline earth solid complexes of pyromellitic acid (1,2,4,5-benzenetetracarboxylic acid, H 4 L) is reported. The insoluble Na + species is Na 2 LH 2 . K + , Rb + and Cs + form MLH 3 . The stoichiometry of precipitation of H 4 L with Ca 2+ , Ba 2+ and Sr 2+ depends on pH: at pH 2 is formed; in the range 4 2 and M 2 L; and at pH > 4.5, only M 2 L is formed. The p K s0 of all the species were determined. The insoluble compounds were also characterized by thermogravimetric analysis.

Thermogravimetric and differential scanning calorimetric methods by stereoscopic and polarising microscopy to identify the nucleus, and IR spectroscopy and X-ray analysis as ancillary analytical tools are applied to the analysis of prostatic calculi.

The thermal properties of some complexes of the Ni(II) with the pyridine-2-aldoxyme (PaOH), where the ligand appears either as ion (PaO − ) or as a neutral molecule, were determined using TG, DTA, HTRS and DRS techniques. The thermal stability, as determined by procedural decomposition temperatures, was The thermal stability is discussed in terms of the intermolecular bonds of the solid lattice and of the electronegativity of the ligands. The thermal decomposition mechanism of the [Ni(PaOH) 2 Cl 2 ] is also examined.

Many enzymatic reactions yield volatile products either directly or by cascade sequences, so it seems possible that head-space chromatography might be used to determine enzymatic activity. The activity of urinary kallikrein, as arginine esterase, has been determined in this way by using the Nα-acetyl- l -phenylalanyl- l -arginine ethyl ester as substrate and measuring the ethanol yielded on incubation for 10 min at 30°, followed by quenching of the reaction. The method has been applied to aqueous solutions and urine.

The thermal properties of nickel(II) and zinc(II) complexes of saccharin (sacc) (o-benzoic sulphimide) have been studied and compared both with those of cobalt(II) and copper(II) previously studied and with those of ternary complexes of nickel(II) and zinc(II) having both saccharin and pyridine as ligands. The thermal behaviour is discussed in terms of the interaction between metal and ligands, interaction studied by IR spectroscopy, and by reflectance spectroscopy. The classical thermal stability scale Co(II) > Ni(II) > Cu(II) > Zn(II) is always obtained.

The imidazole ring appears in a number of biological ligands and many different parameters, such as basicity of the ligands, π-electron acceptor ability, steric factors, hydrogen bonding, etc., play an essential role either on the structural types of coordination or on the thermal characteristics of the coordination compounds obtained by reaction of imidazole and its derivatives with transition metal ions. The influence of some of these parameters on the thermal properties of coordination compounds obtained by reaction of imidazole (Im) and N-methyl imidazole (NmIm) with Co(NO3)2, NO(NO3)2 and Cu(NO3)2 is studied here by means of thermogravimetric and differential scanning calorimetric methods supported by infrared spectroscopy. The compounds obtained were Me(L)n(NO3)2 (Me=Co(II), Ni(II), Cu(II); n = 4, 6). The imidazole complexes are always more stable than the corresponding N-methyl imidazole complexes and the ΔH value corresponding to metal-ligand bond breaking is higher for the imidazole compounds. The decomposition mechanisms are also discussed.

The potassium and sodium salts of some penicillins and cephalosporins were analyzed by thermoanalytical techniques (TG, DTG and DSC); in particular, those antibiotics whose thermal decomposition in oxygen occurs too quickly. The analyses were carried out in atmospheres of static air and oxygen, with and without the addition of ammonium sulphate or ammonium persulphate. It is possible to evaluate the purity of these antibiotics from the resultant sodium or potassium sulphate residue. Better results in terms of accuracy and precision were obtained by the addition of ammonium sulphate or persulphate to the analyzed compounds.

The two most commonly used spectrometric methods for the determination of the phosphorus content of human bile are compared. The optimum experimental conditions are studied, and the analytical characteristics of the two methods, using both standard samples and human bile, are evaluated. The methods are compared on the basis of their sensitivity, precision and accuracy, and the correlation between the two techniques demonstrated using fifteen samples of human bile. Data obtained by both methods have been used to calculate lithogenic index values.

A high-performance liquid chromatographic analysis with fluorimetric detection is described for the quantitative determination of norfloxacin in renal, prostatic tissues and in plasma. The analytical procedure in the tissue pretreatment, consists of purification of the obtained sample by a solid state extraction and quantitation by HPLC. The samples were chromatographed on a C 8 reversed-phase column. Analytical recoveries ranged from 95.2 to 97.6%. Within and between day precision were assessed by analysing serum containing 50 and 500 ng/ml norfloxacin. At each concentration, within day precision was ⩽3.6% (relative standard deviation, n = 10) and day-to-day precision was ⩽5.3% ( n = 10). Limit of detection was ca 1 ng/ml.

Quality control carried out in England has shown the very low reliability of the analysis of renal calculi. Many different analytical techniques have been proposed to solve this problem, and are briefly and critically reviewed in this paper. A method based on thermoanalytical techniques is proposed for obtaining reliable results. The pure substances commonly present in the calculi were first characterised by thermal analysis, derivative thermal analysis, and differential thermal analysis. Synthetic mixtures were then analysed as pellets, simulating the composition of the calculi, and finally, natural renal calculi were studied. The calculi were analysed after dissection, examination by stereoscopic microscopy and polarised light being used to identify a possible nucleus which, when present, was isolated and analysed separately. More than 1000 calculi derived from surgery or from spontaneous emission were analysed. No pretreatment of the calculi is required. The accuracy of the results is about 1.5% and the time required for analysis is about 20 min.

An analytical method for the quantitative determination of some aminoacids is proposed. The analysis is carried out in two steps. The first is based on a thin layer chromatographic separation (TLC) which is realized on alumina and allows the aminoacids to be separated. The second is based on an application of differential scanning calorimetry (DSC), by which it is possible to characterize and determine the amount of the compound contained in each spot, after having removed from the plate the layer corresponding to the spot. This is put in the sample capsule of the differential scanning calorimeter, while the reference capsule is filled with an identical weight of the sample-free aluminium oxide from the same TLC plate. The DSC signal is proportional to the quantity of the sample present in the spot.

A potentiometric method based on phosphate precipitation with Pb2+ and on a lead ion selective electrode is applied to the determination of bile phosphates. The method is rapid and simple and does not require extensive sample pretreatment.

The problem of water content modification in tissues, induced by Dupuytren's disease, is treated by differential scanning calorimetry (DSC) and thermal analysis. Two different types of water are found in the pathological tissue instead of the only one found in healthy tissue. At the same time quantitative analysis shows an increase in the total water in the pathological tissue. Finally, the ratio of the heights of the two maxima found in the pathological tissue is proposed as a diagnostic parameter for the evaluation of the development of the pathology.

Complexes of general formula M[H 2 B(Me 2 pz) 2 ] 2 , [where M = Co(II), Ni(II), Cu(II), and Zn(II)] are characterized by thermal analysis and complementary techniques. Mixtures of boron and metal oxides are found as final residues. Relative thermal stability (Ni > Cu > Co = Zn) and thermal behaviour are discussed. Melting and sublimation data are compared with those referred to in the literature.

A series of conjugated and unconjugated cholate sodium salts was analyzed by thermogravimetric (TG and DTG) techniques. The analyses were carried out in static air and oxygen atmosphere. The final residue of the thermal decomposition is sodium carbonate for the glycoconjugates and unconjugated cholates, and sodium sulphate for the tauroconjugates. The possibility of determining the purity of the cholate sodium salts examined, by analysis of the percentage of sodium present in the compounds, was evaluated. Results concerning accuracy and precision for the examined compounds are reported.

A high-performance liquid chromatographic method with fluorimetric detection is described for the quantitative determination of norfloxacin in renal and prostatic tissues and in plasma. It consists of tissue pretreatment, purification by solid-state extraction and separation and quantification by high-performance liquid chromatography on a C8 reversed-phase column. Analytical recoveries ranged from 95.2 to 97.6%. Within-day and between-day precision were assessed by analysing serum containing 50 and 500 ng/ml norfloxacin. At each concentration, the within-day precision was less than or equal to 3.6% (coefficient of variation; n = 10) and the day-to-day precision was less than or equal to 5.3% (n = 10). The limit of detection was 1 ng/ml.

A multiresidue method was developed and validated for the determination of pesticide residues (omethoate, dimethoate, carbendazim, propoxur, thiabendazole, carbaryl, pirimicarb, azinphos-methyl, methidathion, and iprodione) in fruit juices. The samples were extracted by matrix solid-phase dispersion with diatomaceous earth and analyzed by liquid chromatography/tandem mass spectrometry. The method detection limits were