Dept Food Science University of Udine Via Sondrio, 2/A 33100 Udine - I
lanfranco.conte@uniud.it
Born in 1953, may, 22nd, Educational: Secondary School Diploma as Expert in Chemistry, Graduation in Biological Sciences at Bologna University in the Academic year 1976/77 by an experimental thesys in the field of Fermentative Chemistry. Professional: 1972: Some months of experiences on industrial effluent depuration at Sutcliffe&Speakman, Leight, Lancashire, UK 1973-1982, cooperation in researches in the field of chemistry and technology of fats and oils at Institute of Industrie Agrarie of Bologna University; main topics of research: purity and quality of vegetable oils and lipid; researches on autooxidation of fats, studied both on model system (methyl oleate and methyl linoleante and linolenate) and on authentic samples, evaluation of chemical composition of several natural substances/foods a royal jelly, honeys, vinegars. 1982-1992 Chief analyst at laboratory for Food Fraud Detection of the Italian Ministry of Agriculture; within this frame, he was engaged in activity of control and fight against frauds, e.g. detection of seeds oil in olive oils, extraneous milk in buffalo and sheep cheese, methanoland diethylene glycol in wines and extraneous sugars in wines. In the same years, cooperation with Institute of Marine Biology, researches dealing with composition of sterols and hydrocarbons of different marine organisms and evaluation of composition of lipid fraction of plankton. In academic years 1987/88, 1988/89 and 1989/90, he was contract professor of Food Industry at Udine University and in 1991/1992 contract professor of food industry at Ancona University 1992-1994 Associate professor in Food Chemical Analysis at Udine University, 1994-nowadays professor of Food Chemical Analysis, Fats and Oils Chemistry and Technology, Food Chemistry and Food Quality and Legislation.
Academic roles 1995-2003 Chairman of Educational Committee of Course of “Laurea” in Food Science and Technology 1999-2001 member of Evaluation Board of Researches, Educational and Administration (Nucleo di Valutazione) of Udine University. 2000-2003 Head of Department of Food Science; 2003- 2009 Chairman of Course of “laurea” in Food Science and Technology
Professional roles 1985-nowadays Member of Italian Technical Committee for Fats and Oils (Ministry of Industry), from 2009 chairperson of subcommittee Vegetable Oils 1993- 2001 Chairman of EEC Olive Oil Chemical Experts Group (DG VI); 1997- 2000 Chairman of Oil Chemistry Committee of International Olive Oil Council (IOOC). 2000-nowadays Chairman of Italian Ministry of Agriculture Subcommittee for Analytical methods of fats and oils; 2001- nowadays he is italian delegate at EEC Olive Oil Chemical Experts Group (DG VI) In 2009, L.Conte was a member of Quality and Impact board at University of Uppsala, engaged in evaluation of Research of Food Chemistry and Technology Unit. 2008 - nowadays, member of Certification Committee of AQUA FVG mark 2009 - nowadays member of Certification Committee (now Board for Surveillance of Independence) of North East Institute for Quality (INEQ - Italy)
Other informations L.Conte is member of Italian Chemical Society (divisions of Food Chemistry and of Science of Separation) and President of Italian Society for Fat Researches, Chairperson of Olive Oil Division of Euro Fed Lipid.
L. Conte has been teacher in a number of courses of Masters in Quality Olive oil Production (Master at University of Pisa, Perugia and Teramo) and within the framework of courses for professional developing in the field of olive oil production and educational of olive oil tasters, all recognysed by Italian Ministry of Agriculture. In the field of fatty substances, his researches have dealed with natural sources of lipids charachterization, olive oils purity and quality assessment, as well as studies on model system dedicated to fats autooxydation, both for what is concerning fatty acids as well as sterols. The influence of unsaturation as lipid oxidation promotion factor was studied as well as the influence of antioxidant substances. The antioxidant activity of phenolics of virgin olive oils, as well as the antioxidant activity of plant extracts (Labiatae family) and of a number of essential oils was studied by means of several approaches to its evaluation. In the latter case, activity was checked on different unsaturated substrates (swine fat and soybean oil). Also problems regarding the presence of some xenobiotics (PAHs) were studied in deep. Within this latter field, the evaluation of substances present as traces lead him to be engaged in the development of dedicated analytical methods and instrumentations, as well. Wide attention has been devoted to coordinated (SPE-GC, SPE-LC) and hyphenated techniques (LC-LC, LC-LC-GC) In other fields, he worked on honeys characterisation, also coordinating some national ring test for method assessment. He also developed a number of researches on volatiles compounds of several foods as honeys, salami, alcoholic and non alcoholic beverages, meat preserves, virgin olive oils, cheese; methods applied were based on dynamic stripping and cold trapping and solid phase microextraction.
Abstract: The bacteria fatty acid profile has been extensively studied for taxonomic classification purposes, since bacteria, in general, contain particular and rare fatty acids, compared with animal and plant tissues. As for any real-world sample type, the development of rapid and reliable methods for (i) sample identification (in this case, bacterium type), and (ii) constituent identification (in this instance, the fatty acid profile) is desirable. In this research, a half-an-hour procedure, to analyze bacteria, was developed: a 2-min one-step sample preparation step was followed by a relatively fast comprehensive 2D GC-MS separation (25âmin). Furthermore, dedicated MS libraries were constructed for the identification of bacteria and fatty acids. Finally, data processing, only qualitative at this stage, was carried out with the support of a novel comprehensive 2D GC software
Abstract: (GCÃGC) is a powerful technique which can enable a great
increase in GC peak capacities. However, since secondary-
column separations are very rapid, detectors with a
fast acquisition rate are mandatory. Such a requirement
has certainly limited the use of the quadrupole mass
spectrometer in the GCÃGC field. The present research
is focused on the evaluation of a novel rapid-scanning
quadrupole mass spectrometry (qMS) detector, characterized
by a 20 000 amu/s scan speed and a 50 Hz scan
frequency, using a 290 amu mass range (40-330 m/z).
The performance of the MS system was assessed by
analyzing mixtures of 24 allergens, as well as a perfume
sample, through GCÃGC/qMS. The MS parameters evaluated
at different acquisition rates (50, 33, and 25 Hz),
as well as in the (simultaneous) scan/selected ion monitoring
(SIM) mode, were the number of data points per
peak, mass spectrum quality, peak skewing, and sensitivity.
Two GCÃGC/qMS methods, using the 50 Hz acquisition
rate and the scan/SIM mode, were validated. Both
methods provided similar results in terms of repeatability,
accuracy, and linearity, while a great increase in sensitivity
was observed (ca. a factor of 10) under scan/SIM conditions.
The validated method proved to be suitable for the
analysis of perfume allergens, according to the requirements
of Directive 2003/15/EC.
Abstract: In the present research, a split-flow comprehensive 2-D GC-quadrupole MS (qMS)
method was developed using: a primary apolar 30m0.25mm id0.25 mm df capillary
linked, via a T-union, to a secondary polar 1.0m0.05mm id0.05 mm df capillary and
to a 0.10m0.05mm id0.05 mm df uncoated column segment. The GCGC-qMS
instrument was equipped with two GC ovens and a loop-type modulator. The polar
column was connected to the MS, whereas the uncoated column directed most of the firstdimension
effluent to waste and enabled the generation of optimum gas velocities in both
dimensions, namely circa 20 and 80 cm/s in the first and second dimensions, respectively.
The rapid-scanning qMS was operated at a scan speed of 10 000 amu/s, a 25-Hz data
acquisition frequency (scan time1interscan time: 40 ms), and with a normal GC mass
range (m/z 40â360). Chromatography bands at the second-dimension outlet were never
less than 360 ms wide (6s), enabling the acquisition of at least 10 spectra/peak.
Abstract: The focus of the present research is directed toward the
development of a comprehensive two-dimensional gas
chromatography (GC Ã GC) method, characterized by a
greatly increased separation power, if compared with GC
à GC approaches using classical column combinations.
The analytical objective was achieved by using a 0.05 mm
internal diameter (i.d.) capillary as second dimension, a
split-flow approach reported in previous research (Tranchida,
P. Q.; Casilli, A.; Dugo, P.; Dugo, G.; Mondello,
L. Anal. Chem. 2007, 79, 2266-2275), and a twin-oven
GC Ã GC instrument. The column combination employed
was an orthogonal one: an apolar 30 m à 0.25 mm i.d.
column was linked, by means of a Y-union, to a flame
ionization detector (FID)-connected high-resolution 1 m
à 0.05 mm i.d. polar one and to a 0.20 m à 0.05 mm
i.d. uncoated capillary segment; the latter was connected
to a manually operated split valve, located on top of the
second GC. As previously shown, the generation of
optimum gas linear velocities in both dimensions can be
attained by splitting gas flows at the outlet of the first
dimension (Tranchida, P. Q.; Casilli, A.; Dugo, P.; Dugo,
G.; Mondello, L. Anal. Chem. 2007, 79, 2266-2275).
An optimized GC Ã GC method was developed and
exploited for the analysis of a complex petrochemical
sample. The satisfactory results attained were directly
compared with those observed using the same instrumentation,
equipped with what can be defined as a
classical GC Ã GC split-flow column set: the same primary
column was connected to an FID-linked 1 m à 0.10 mm
i.d. polar one and to a 0.30 m à 0.10 mm i.d. uncoated
capillary. It will be herein illustrated that there is still
room for significant progress in the GC Ã GC field.
Abstract: The present research is based on the full exploitation of the separation power of a 0.05mm internal
diameter (ID) capillary, as a comprehensive two-dimensional (2D) GC (GCÃGC) secondary column, with
the objective of attaining very high-resolution second dimension separations. The aim was achieved by
using a split-flow system developed in previous research [P.Q. Tranchida, A. Casilli, P. Dugo, G. Dugo,
L. Mondello, Anal. Chem. 79 (2007) 2266], and a dual-oven GCÃGC instrument. The column combination
employed consisted of a polar 30mÃ0.25mm ID column connected, by means of a T union, to a
detector-linked high-resolution 1.1mÃ0.05mm ID apolar analytical column and to a 0.33mÃ0.05mm
ID retention gap; the latterwas connected to a manually operated split valve. As previously demonstrated,
the use of a split valve enables the regulation of gas flows through both analytical columns, generating the
most appropriate gas linear velocities. Comprehensive 2D GC experiments were carried out on Arabica
roasted coffee volatiles (previously extracted by means of solid-phase microextraction) with the splitvalve
closed (equal to what can be defined as conventional GCÃGC) and with the split-valve opened at
various degrees. The reasons why it is absolutely not effective to use a 0.05mm ID column as second
dimension in a conventional GCÃGC instrument will be discussed and demonstrated. On the contrary,
the use of a 0.05mm ID column as second dimension, under ideal conditions in a split-flow, twin-oven
system, will also be illustrated and discussed.
Abstract: Fat is present in bakery foods, as a natural component of ingredients or it is added in the formulation for rheological, technological and sensorial reasons. However the presence of fat can lead to oxidation problems during the shelf life of the products, also aVected by cooking temperatures.
The control of the oxidative status deals with two issues: the insurance of food safety for consumers and economic aspects for companies. This work points out the possibility to use hexanal as unique index for oxidation status and it suggests a fast solid phase microextraction (SPME) method to analyze it.
Abstract: A rapid extraction method involving microwave assisted extraction (MAE), followed by sample clean-up
on a silica cartridge, reversed-phase high performance liquid chromatography (RP-HPLC) and spectrofluorimetric
detection, was optimised for polycyclic aromatic hydrocarbon (PAH) determination in smoked
meat. Compared to solvent extraction assisted by sonication, MAE, carried out with n-hexane on 2 g of
lyophilised sample at 115 C for 15 min, allowed to obtain better extraction efficiencies. Limits of quantification
(LOQ, s/n = 10) lower than 0.2 lg/kg wet weight were found for all PAHs, except for Fl (0.3 lg/
kg), P (0.6 lg/kg) and IP (0.4 lg/kg).
The optimised procedure, that presented good analytical performances (with recoveries ranging from
77% to 103%, and precision within 10% for most of the PAHs), was applied to determine PAH content in
different smoked meat products from the Italian market.
Abstract: Nowadays the quality of food is a multifactorial concept, which include safety,
nutritional and edonistic aspect. Concerning the safety problems, it is
important to assess the presence of undesirable compounds, which can affect
negatively the normal organism physiology. The sources of these substances
can be external (environmental pollution) or internal (related to
degradation of some components). Among the external pollutants, polycyclic
aromatic hydrocarbons (PAH) are ubiquitous toxic compounds, which
can be present in the foodstuff due to environmental pollution or to technological
process, included heating process. Among the substances derived
from degradation, there are some compounds used as a marker of oxidation,
which are a marker of the presence of free radical, and are related to
total or partial reduction of the nutritional value of the foodstuff. It is important,
anyway, to consider these problems from a farm to fork point of
view, also for animal products. The aim of this paper was to investigate on
PAH contamination of 4 different types of feeds (and corresponding ingredients)
and possible transfer of PAH contamination to the meat of 4
groups of pigs (of 8 pigs each) feeded with the 4 different formulations.
Rapid sample preparation procedures, involving microwave assisted extraction
(MAE) followed by a clean-up step on a SPE silica cartridge and final
determination of PAHs by RP-HPLC connected to a spectrofluorometric
detector, were developed at this purpose. Feedstuffs showed benzo[a]pyrene
(BaP) mean amounts ranging between 0.037 and 0.107 ppb. Among
feed ingredients, the most contaminated resulted to be tender wheat bran
and soybean (BaP mean amounts of 0,248 and 0,153, respectively), while
barley and corn showed the lowest contamination levels. All the meat samples
showed similar and very low contamination levels, to confirm the fact
that PAHs ingested with feeds are rapidly metabolised. As demonstrated
by the similarity between PAHs profiles of feed and meat samples, PAHs
found in meat samples seems to derive from environmental contamination
occurring during sample manipulation. The volatile fraction was assessed
on feed, raw material and meat. Particular attention was paid for marker of
secondary oxidation, like hexanal. For this purpose, as applied for other
matrices, solid phase microextraction (SPME) was used. The results obtained
showed a low amount of hexanal, between not detectable (<0.2 μg/kg)
2
VOLUME 10
and 20 μg/kg. Among the raw material, soybean presented the lowest
amount (from <0.5 to 0.6 μg/kg), instead the quantity in barley was variable.
The feeds showed high amount of hexanal: control fodder had 134 ±
69 μg/kg of hexanal, fodder + oil + vitamin E had 146 ± 72 μg/kg, fodder
+ sunflower oil had 182±32 μg/kg, fodder + vitamin E had 161 ± 67 μg/kg.
The meat samples presented hexanal, eptanal, octanale, nonanale, butanoic
acid and hexanoic acid, but in lower amount than feed.
Abstract: Polycyclic aromatic hydrocarbons (PAHs) are a large class of organic compounds. It
has been established that the main source of exposure to these compounds for
human beings is through food, particularly fats and oils, due to the lipophilic
nature of these polycyclic compounds. The aim of this work was to optimise and
validate a method involving SPE and HPLC for rapid determination of the 16 European
Union (EU) priority PAHs (required by the Recommendation 2005/108/EC) in
vegetable oils. Two spectrofluorometric detectors and a UV-Visible detector in series
were used to identify and quantify the target compounds. Linearity, recoveries,
LOD, and LOQ were found to be in agreement with the performance criteria for benzo[
a]pyrene (BaP) analysis as required by the Commission Directive 2005/10/EC, and
satisfactory for all the compounds of interest, except for cyclopenta[c,d]pyrene,
which presented a very low signal in the UV. Optimised chromatographic conditions
for the separation of 25 PAHs, comprising both EPA and EU priority PAHs plus
benzo[e]pyrene and benzo[b]chrysene, have been also proposed.
Abstract: A solid-phase microextraction method coupled with comprehensive gas chromatography and time-of-flight mass spectrometry for the determination of polycyclic aromatic hydrocarbons in vegetable oils has recently been reported. The present paper tested the possibility to use the solid-phase microextraction method coupled with one-dimensional gas chromatographyâmass spectrometry of the only benzo[a]pyrene. Furthermore, an inhouse
validation for benzo[a]pyrene, used as a marker, as requested by the European regulation no. 208/2005, was carried out. Statistical tests were performed to elaborate the data. Linearity was satisfactory (r2 = 0.999), between about 0.5 and 15 g/kg. Detection limit and quantification limit were 0.17 and 0.46 g/kg, respectively. In-day and inter-day repeatability were less than 6% in both cases.
Abstract: A simple and fast solid-phase microextraction method coupled with comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry was developed for analysis of polycyclic aromatic hydrocarbons in edible oil, performed directly in a hexane solution of the oil. Sampling conditions (solvent used, extraction time, extraction temperature and fiber rinsing time) were optimized by using a sample of oil
fortified with a standard solution of polycyclic aromatic hydrocarbons. The methodwas validated by calculating linear range, correlation coefficient, accuracy, repeatability, detection limit and quantification limit. The method was applied to several oils collected from the market and directly from an olive pomace extraction pl
Abstract: involving an homogenisation step with 0.1 M HCl, was applied. Two different derivatization procedures (using o-phthaldialdehyde and dansyl chloride) were applied on different aliquots of the same acid extracts and HPLC analyses were carried out with the same reversed phase (C18) HPLC column. Results obtained with the two procedures were compared. With the exception of sauerkraut, putrescine (0.2â0.5 mg/100 g fresh weight) and spermidine (0.4â4.5 mg/100 g) were always the ost represented amines, generally followed by spermine (maximum 1.1 mg/100 g). Tyramine level was 4.9 mg/100 g in canned sauerkraut while other samples presented levels not exceeding 1.2 mg/100 g. The spinach sample showed the highest histamine content (2.0 mg/100 g).
Abstract: The Italian Society for the Study of Fatty Substances, in cooperation with Italian Istituto Superiore di Sanità carried out a collaborative study involving 19 laboratories, with the aim to acquire a preliminary evaluation of methods applied to assess PAHs in fats and oils. Furthermore, the results obtained from these methods were evaluated to see to what extent they were in agreement. The methods used to evaluate the individual
PAHs are complex, and, even if some laboratories have tried to harmonize them, most prefer to apply well known and reliable methods. This approach is in agreement with the more recent indications of UE (Reg (EC) 208/2005, Recommendation of 4 February 2005 Official Journal of the European Union L 34 8.2.2005 and Directive 2005/10/EC) that suggest that any suitable method is applicable, if it works in agreement with
some selected characteristics. Of course, the analytical methods applied by different laboratories which participated in this study, did not form an exhaustive list of all analytical methods used by Italian laboratories. Results were in good agreement when highly contaminated oils were analysed but some problems arose with very low concentrations. When a sample on the borderline of the UE limit (2ppb) was analysed, most laboratories were able to obtain a correct classification of the sample.
Abstract: An on-line LCâGC method was used to assess the n-alkane composition of 40 olive oil samples obtained from three different cultivars from a restricted grove zone in Croatia. Olive samples were handpicked at three different ripening stages during four consecutive years. No significant differences were found in relation to the variable ââperiod of harvestingââ, while the effects ââvarietyââ and ââyearââ as well as their interaction caused significant differences for most of the n-alkane components (p60:05). Despite the influence of the production year, linear discriminant analysis based on the n-alkane components was able to correctly identify the
variety of 97.5% of the samples
Abstract: A reliable, simple and relatively fast method for the simultaneous determination of volatile and semi-volatile aromatic hydrocarbons in virgin olive oil was developed, based on headspace solid-phase microextraction (HS-SPME). The investigation regarded eco-contaminants such as alkylated monoaromatic hydrocarbons from C1- to C4-benzenes and light polyaromatic hydrocarbons up to four aromatic rings.
Sampling and chromatographic conditions were optimized by using standard solutions in deodorized olive oil and the analytical performances of the method were determined. The proposed method was then applied to real samples of virgin olive oil were the target hydrocarbons could be identified and quantified. Several of them had not been previously quantified in virgin olive oil. Moreover, by the analysis of olive oil samples an additional number of C4-benzenes could be tentatively identified.
Abstract: It is well known that olive oils are the only foods whose legal control must also involve sensory
evaluation, and that a harmonised protocol is used for this purpose: EEC regulation 2568/91 and an IOOC
trade norm of the 1990s introduced a standard method among those used to assess the quality of virgin
oils, after which a modified method known as the âpanel testâ was developed and adopted, firstly by the
IOOC and later by the EEC. One problem in applying the panel method often depends on the lack of
reference standards for training judges, in addition to, in some cases, a lack of exact knowledge of the
origin of some defects; for these reasons, several judges have suggested the unification of some defects,
even when these originate from different kinds of problems. In this paper we have applied headspace
analyses to a number of samples of oils that were also characterised by a panel. Besides the samples,
standard defective oils obtained by the IOOC and used for training sensory judges were also analysed, with
the aim of obtaining a model for use in method validation. Seventy-six peaks were detected and most of
them identified by gas chromatography/mass spectrometry; their distribution was different in the samples
characterised by different defects as assessed by the panel test. The well-known compounds of virgin olive
oils were detected, including the series of C6 compounds, whose importance in defining positive (âgreenâ
flavour) and negative (rancid) characteristics of olive oils is well known. No samples classified as extra
virgin ever present peaks with magnitudes as great as those found in defective oils. Chemometric data
evaluation was carried out and samples were clustered on the basis of the headspace composition; the
results were found to agree with those of the panel test, so a number of compounds were related to the
presence of particular defects.
Abstract: Hopanes, triterpenoid hydrocarbons formed under geological conditions, were analysed to confirm the mineral origin of the unresolved complex mixtures of hydrocarbons observed in the gas chromatography with flame ionization detection chromatograms of human milk and certain foodstuffs. The ârelative hopane contentâ
(RHC) is introduced, i.e. it is the area ratio of the sum of the hopanes and the paraffins in the same segment of the chromatogram. The RHC in various mineral oil products (motor oils, hydraulic oils, lubricating oils, Vaseline) was 3.4%, with a relative standard deviation of 19%. The RHC determined in samples of vegetable oils, mussels and clams as well as of human milk containing an unresolved complex mixture of hydrocarbons was in the same range,
confirming that these samples were contaminated by mineral oil material.
Abstract: The efficiency of headspace solid-phase microextraction (SPME) was evaluated for the qualitative and semi-quantitative analysis of virgin olive oil volatile compounds. The behaviour of four fibre coatings was compared for sensitivity, repeatability and linea ity of response. A divinylbenzeneâCarboxenâpolydimethylsiloxane fibre coating was found to be the most suitable for the analysis of virgin olive oil volatiles. Sampling and chromatographic conditions were examined and the SPME method, coupled to GC with MS and flame ionization detection, was applied to virgin olive oil samples. More than 100 compounds were isolated and characterised. The presence of some of these compounds in virgin olive oil has not previously been reported. The main volatile compounds present in the oil samples were determined quantitatively
Abstract: Modifications of virgin olive oil subjected to accelerated storage were evaluated by HS-SPME analysis.
To find a suitable marker of oxidative degradation, the volatile compounds showing variable
concentration during the oxidative process have been identified and quantified by SPME coupled to
GC-MS and GC-FID, respectively. The SPME analysis results were then compared with the
parameters usually applied to assess the oxidative status of lipids, such as peroxide value,
spectrophotometric absorbance, and loss of unsaturated fatty acids. Finally, the assessment of nonanal
has been suggested as a marker of oxidative degradation. This rapid, inexpensive, and reliable method
may allow screening of oils prior to testing by a panel of assessors.
Abstract: SPME was employed to characterize the volatile profile of virgin olive oils produced in two geographical
areas of northern Italy: the region of the Gulf of Trieste and the area near Lake Garda. There are as
yet no data on the headspace composition of virgin olive oils from these regions, characterized by
particular conditions of growth for Olea europaea. Using the SPME technique coupled to GC-MS
and GC-FID, the volatile components of 42 industrially produced virgin olive oil samples were identified
and the principal compounds quantitatively analyzed. Significant differences in the proportion of volatile
constituents from oils of different varieties and geographical origins were detected. The results suggest
that besides the genetic factor, environmental conditions influence the volatile formation.
Abstract: The assessment of the botanical origin of unifloral honeys is an important application in food control. The current official methods mainly use pollen analysis. The aim of this paper is to present an SPME analytical approach to the study of honey volatiles. Honey samples (40) obtained from hive sites in different regions of Italy were analysed. The samples had six different botanical origins: citrus (five), chestnut (10), eucalyptus (eight), lime tree (11), thyme (two) and dandelion (four). Melissopalynological analysis was also performed. Identification of volatile compounds was carried out by SPME/GC/MS analysis, and quantitative evaluation was done by SPME/GC/FID analysis for compounds with wellresolved peaks. Using the SPME method, all samples with the same botanical origin gave remarkably similar GC profiles. Some volatile compounds were found only in specific floral source honey samples and thus could be interesting for use as markers.
Abstract: The solid phasemicroextraction techniquewas tested for thymol evaluation in honey. Thymol can
be present in honey as a residue of treatments against Varroa destructor Honey was sampled from apiaries
treated with anti-Varroa products whose active ingredient is thymol. Thymol evaluation was done using the
internal standardmethod; benzophenone and carvacrol were tested as internal standards/ the best results were
obtained using benzophenone. The application of an alkaline hydrolysis was important for obtaining quantitative
recoveries.
Abstract: Despite the carcinogenic properties of some PAHs, and although edible oils are particularly prone to PAH contamination, no international legal limits for PAH in edible oils have been yet established. However, a number of methods for such analyses have been published, most of which are time consuming and unsuitable for routine analysis, as they do not permit analysis of a large number of samples per day. Since sample preparation is the most time-consuming part of analysis, research to find fast sample preparation methods is of topical interest. In this paper, solid phase extraction with silica cartridges is applied as sole sample preparation step. A 250-mg smaple of oil in n-hexane is loaded onto a 5 g silica cartridge and the PAH fraction is eluted with
8 mL of n-hexane/dichloromethane 70/30. After solvent evaporation, the volume was adjusted to 100 lL and injected into a HPLC equipped with a C18 reverse phase coöumn and a spectrofluorometric detector. Results show a relatively low recovery for the more volatile PAHs (Na and Ac) and good recovery for heavy PAHs. Repeatability is quite satisfactory, as coefficients of variation range between 5.0 and 13.0%.
Abstract: This review deals with analytical methods for polycyclic aromatic hydrocarbon (PAH) determination in oils and fats. The data reported in the introduction deal with PAH dietary intake from this group of food and contamination levels recently found by some authors in different vegetable oils, stressing the importance of establishing a method suitable for routine analyses. Traditional sample preparation relies on tedious, time-consuming procedures. They generally consist of an extraction step (liquidâliquid partition, caffeine complexation, saponification) followed by one or more purification procedures (column chromatography, thin-layer chromatography, solid-phase extraction). The analytical determination is usually carried out by HPLC and spectrofluorometric detection, or through high-resolution capillary GC coupled to flame ionisation detection or mass spectrometry. LC is a valid alternative to the traditional sample preparation, and off-line LCâLC
allows performing an accurate PAH analysis in less than 2 h. Also supercritical fluid extraction, allowing performing both extraction and clean-up in one combined step, is a promising technique. Hyphenated techniques such as LCâGC and LCâLCâGC seem to be very promising. A completely on-line method for alkylated PAH determination in oils or lipidic extracts contaminated with mineral oil involves a two-dimensional LC-step with intermediate eluent evaporation and GC transfer through a vaporiser /overflow interface.
