M.C. Gennaro

A new hydrophilic interaction liquid chromatography tandem mass spectrometry method for the simultaneous determination of seven biogenic amines in cheese

An HILIC-PI APCI MS/MS method is developed for the determination of seven biogenic amines (cadaverine, histamine, putrescine, spermidine, spermine, tryptamine and tyramine) in cheese. Their presence and relative amounts give useful information about freshness, level of maturing, quality of storage and cheese typicization. The major drawback in the analysis is represented by the relevant matrix effect and the general unbalanced concentrations of the different amines in cheese. The method proposed represents an improvement with respect to an HPLC-MS/MS method already developed in this laboratory. The new method permits better sensitivities it makes use of a Waters Atlantis HILIC (150.0 mm x 2.1 mm i.d., 3 microm) stationary phase and of a mobile phase of acetonitrile and ammonium formate 50.0 mM in ultrapure water brought to pH 4.00 for formic acid, flowing under gradient conditions. The chromatographic system is interfaced with a 3200QTrap LC-MS/MS system (Applied Biosystem, Foster City, CA, USA) by a Turbo V interface equipped with Heated Nebuliser (APCI) and Turbo Ion Spray (TIS) probes. LOQ values lower than 10 microg L(-1) are obtained. The method is applied in the analysis of Castelmagno cheese.

Derivatization, identification and separation of carboxylic acids in wines and beverages by high-performance liquid chromatography.

A high-performance liquid chromatographic method for the derivatization, identification and separation of carboxylic acids in beverages such as wines and other commercial drinks or natural fruit juices has been developed. The accuracy and precision of the method are discussed with reference to specific methods for the determination of single acids. Applications to the analysis of different wines and beverages are demonstrated.

Neural network and experimental design to investigate the effect of five factors in ion-interaction high-performance liquid chromatography

The effect of five experimental parameters on the ion-interaction chromatographic retention of pesticides characterized by different polarity was investigated by means of experimental design and artificial neural network treatments. The factors considered were: (1) the mobile phase pH; (2) N, the alkyl-chain length of the IIR (ion-interaction reagent); (3) CM, the organic modifier concentration in the mobile phase (4) CR, the concentration of IIR and (5) F, the flow-rate. The use of fractional design and Hoke design allowed useful information to be drawn about the retention mechanism involved and to build, through artificial neural network treatment (ANN), a model characterised by both descriptive and predictive ability. Four neurons and a bias unit were employed. The ANN proved to be a useful instrument in the optimisation of the chromatographic separation, as regards resolution and total analysis time: the experimental retention obtained in the optimal conditions always differed within 14% from the predicted ones.

Identification and determination of red dyes in confectionery by ion-interaction high-performance liquid chromatography

Abstract In this paper an ion-interaction HPLC method for the separation and determination of red dyes used to decorate home-made sweets is presented. In particular E122, E123 and E124 dyes are considered, with special interest for E123 (amaranth), prohibited by the US Food and Drug Administration in 1976 and by Italian legislation in 1977 and then again permitted (with restrictions) in the European Community in 1994, (94/36 EEC Directive). A RP-ODS stationary phase is used and an ion-interaction reagent (octylammonium phosphate) is added to the hydro-organic eluent [water-acetonitrile (30:70, v/v), pH = 6.4]. Spectrophotometric detection at 520 nm was employed and detection levels below 12 μg/l for the three dyes were achieved. The method is applied to two commercial products, respectively produced in France and in Italy, and the results are discussed in the light of the recent EEC Directive concerning food dyes.

Determination of aromatic amines at trace levels by ion interaction reagent reversed-phase high-performance liquid chromatography : analysis of hair dyes and other water-soluble dyes

Abstract A reversed-phase high-performance liquid chromatographic method, making use of interaction reagents, was developed for the separation and determination of aromatic amines. Different interaction reagents were used and compared. The use of octylammonium salicyte or octylammonium orthophosphate as the interaction reagent and a reversed-phase spherical 5μm RP-18 as the stationary phase, with spectrophotometric detection at different wavelengths, gave good results. The separation of up to seven aromatic amines (the three isomers of phenylenediamine, benzylamine, 2-phenylethylamine, 3-phenylpropylamine and aniline) was obtained with sensitivity levels ranging between 50 and 100 ppb. The method was applied to the analysis of water-soluble dyes such as fabric dyes, brown and blond hair dyes, black shoe dye and black fountain-pen ink. It was possible to detect and determine 1,4-phenylenediamine in commercial hair dyes. The results indicate that very large amounts of this amine are present in these products namely 7320 ppm for brown hair and 598 ppm for blond hair.

How chemometrics can helpfully assist in evaluating environmental data. Lagoon water

Abstract The seasonal dependence of inorganic anion composition of Venice lagoon water was investigated along the period June–November 1993. Monthly samples were collected in three different stations and nitrite, nitrate, iodide, bromide, chloride, sulfate, phosphate and silicate content was determined. Dissolved oxygen, temperature and conductivity were measured in situ. Unfortunately, in that period the weather behaved very atypically as concerns both rains and temperature and the raw data obtained for the variables considered do not allow direct correlations with the season. Only the chemometric treatment of principal component analysis permitted to characterize the samples as a function of seasonality and sampling site and allowed to select the significant discriminating factors.

Separation and determination of inorganic anions by reversed-phase high-performance liquid chromatography

An overview and discussion is given of literature methods published after 1989 devoted to the ion-interaction chromatographic determination of inorganic anions. Seventy references are quoted. Ion-interaction chromatography makes use of commercial reversed-phase stationary phase and conventional high-performance liquid chromatography instrumentation. The basis of the technique, the modification of the stationary phase surface, the choice of the ion-interaction reagent as well as the dependence of retention on the different variables involved are discussed. Examples of application in the fields of environmental, clinical and food chemistry are presented. The experimental conditions of stationary phase, of mobile phase composition as well as detection mode, detection limit and application are also summarized in tables.

Chemometrically Assisted Development of IP‐RP‐HPLC and Spectrophotometric Methods for the Identification and Determination of Synthetic Dyes in Commercial Soft Drinks

Abstract Two independent methods were developed to identify and determinate synthetic dyes and to follow their degradation processes. The IP‐RP‐HPLC method was optimised by the experimental design technique and the results obtained were compared with ones obtained by direct/derivative spectrophotometry. The dyes considered in this study that are representative of soft drink components, are: Tartrazine (E102), Quinoline Yellow (E104), Sunset Yellow (E110), Carmoisine (E122), Amaranth (E123), New Coccine (E124), Patent Blue Violet (E131), and Brillant Blue FCF (E133).

Aliphatic monoamines, diamines, polyamines: An HPLC method for their identification and separation by a dansylation reaction; The study of separation factors in homologous series

SummaryAn analytical method is presented for the identification and separation of aliphatic monoamines, diamines and polyamines. Dansyl chloride as the derivatizing agent and fluorimetric detection were employed. The behaviour of different column packings and eluent compositions was tested and compared. The interaction mechanisms of the dansylated compounds with stationary and mobile phases are discussed on the basis of the analysis of the capacity factors evaluated in the homologous series of monoamines CH3(CH2)nNH2, with n varying up to 9 and diamines NH2(CH2)nNH2, with n varying up to 12. An application of this method to a real sample is presented.

Separation of phenylurea pesticides by ion-interaction reversed-phase high-performance liquid chromatography Diuron determination in lagoon water

An ion-interaction HPLC method is developed for the separation of the phenylurea herbicides asulam, diuron, isoproturon, linuron and monuron. C18 was used as stationary phase and octylammonium phosphate as ion-interaction reagent, in the presence of methanol or acetonitrile as organic modifier. Detection limits lower than 9 μg/l can be obtained without preconcentration steps. The method was applied to the analysis of diuron in a sample of lagoon water. Using liquid-liquid extraction, a diuron concentration of 42 μg/l was found.