Francesc Centrich

High-throughput multiclass method for antibiotic residue analysis by liquid chromatography–tandem mass spectrometry☆

A simple and rapid method has been developed for the residue analysis of 39 antibiotics (tetracyclines, quinolones, penicillins, sulfonamides and macrolides) in foodstuffs of animal origin. The method combines an effective extraction technique, which uses water-methanol as extracting solvent, with ultra-high-pressure liquid chromatography-tandem mass spectrometry, allowing both confirmation and quantification in a single chromatographic run. The multiresidue method has been validated in chicken muscle matrix according to European Union Decision 2002/657/EC. It has been implemented as a routine method in a Public Health Laboratory, instead of the five plates test and LC methods previously used.

Development and validation of a multiclass method for the analysis of antibiotic residues in eggs by liquid chromatography–tandem mass spectrometry

A multiclass method for the analysis of residues, in egg matrices, of 41 antimicrobial agents belonging to seven families (sulfonamides, diaminopyridine derivates, quinolones, tetracyclines, macrolides, penicillins and lincosamides) was developed and validated according to the requirements of European Commission Decision 2002/657. Compounds were extracted with a pressurized liquid extraction (PLE) technique using a 1:1 mixture of acetonitrile and a succinic acid buffer (pH 6.0) at 70 °C. As this resulted in clear extracts, no further clean-up was necessary. Analytes were determined by ultra-high-pressure liquid chromatography-tandem mass spectrometry (UHPL-MS/MS) in a chromatographic run of 13 min. Calibration was carried out with spiked blank samples subjected to the entire analytical procedure. Five compounds, two of them isotopically labelled, were used as internal standards. Most analytes were quantified with errors below 10%. Precision in terms of reproducibility standard deviation was between 10% and 20% in most cases. CCα values were in the range 0.5-3.8 μg kg⁻¹ for the non-authorized compounds. The proposed method would enable an experienced analyst to process about 25 samples per day.

Targeted analysis with benchtop quadrupole-orbitrap hybrid mass spectrometer: application to determination of synthetic hormones in animal urine.

Sensitive and unequivocal determination of analytes/contaminants in complex matrices is a challenge in the field of food safety control. In this study, various acquisition modes (Full MS/AIF, Full MS+tMS/MS, Full MS/dd MS/MS and tSIM/ddMS/MS) and parameters of a quadrupole-orbitrap hybrid mass spectrometer (Q Exactive) were studied in detail. One of the main conclusions has been that, reducing the scan range for Full MS (using the quadrupole) and targeted modes give higher signal-to-noise (S/N) ratios and thereby better detection limits for analytes in matrix. The use of Q Exactive in a complex case, for the confirmatory analysis of hormones in animal urine is presented. A targeted SIM data dependent MS/MS (tSIM/ddMS/MS) acquisition method for determination of eight synthetic hormones (trenbolone, 17α ethinylestradiol, zeranol, stanozolol, dienestrol, diethylstilbestrol, hexestrol, taleranol) and a naturally occurring hormone (zearalenone) in animal urine were optimized to have sensitive precursors from targeted SIM mode and trigger MS/MS scans over the entire chromatograph peak. The method was validated according to EC/657/2002. CCα (decision limit) for the analytes ranged between 0.11 μg L(-1) and 0.69 μg L(-1) and CCβ (detection capability) ranged between 0.29 μg L(-1) and 0.90 μg L(-1).

Total and Inorganic Arsenic in Marketed Food and Associated Health Risks for the Catalan (Spain) Population

Inorganic arsenic (iAs) is considered to be a human carcinogen. In this paper, total (As) and iAs contents of 215 food products and drinks (i.e., seafood, fruits and vegetables, meat products, oils and fats, rice and rice products, seasonings, and alcoholic drinks) marketed in Catalonia (Spain) were quantified by inductively coupled plasma-mass spectrometry. The analytical method described was used for different food products, obtaining feasible results without the need to couple LC-ICP-MS for iAs. Daily As and iAs intakes for the average adult Catalan consumer were estimated at 354 and 6.1 μg/day/person, respectively, using consumption data from the Catalan Nutrition Survey (ENCAT). The highest As content was found in seafood, contributing 96% of dietary As intake, whereas rice presented the highest iAs values, corresponding to 67% of dietary iAs intake. As cooking process may affect iAs content, boiled rice was evaluated, showing an iAs reduction (up to 86%) when using higher water volumes (30:1 water/rice ratio) than those used in previous studies. This iAs exposure was slightly below the exposure risk range stated by the European Food Safety Authority (0.3-8 μg/kg of body weight/day), although the possibility of a risk to the population with high rice consumption cannot be excluded.

Secondhand smoke exposure in hospitality venues in Europe.

Background Although in the last few years some European countries have implemented smoking bans in hospitality venues, the levels of secondhand smoke (SHS) in this occupational sector could still be extremely high in most countries. Objective The aim of this study was to assess exposure to SHS in hospitality venues in 10 European cities. Methods We included 167 hospitality venues (58 discotheques and pubs, 82 restaurants and cafeterias, and 27 fast-food restaurants) in this cross-sectional study. We carried out fieldwork in 10 European cities: Vienna (Austria), Paris (France), Athens (Greece), Florence and Belluno (Italy), Galway (Ireland), Barcelona (Spain), Warsaw and Lublin (Poland), and Bratislava (Slovak Republic). We measured vapor-phase nicotine as an SHS marker. Results We analyzed 504 samples and found nicotine in most samples (97.4%). We found the highest median concentrations in discos/pubs [32.99 μg/m3; interquartile range (IQR), 8.06–66.84 μg/m3] and lower median concentrations in restaurants/cafeterias (2.09 μg/m3; IQR, 0.49–6.73 μg/m3) and fast-food restaurants (0.31 μg/m3; IQR, 0.11–1.30 μg/m3) (p < 0.05). We found differences of exposure between countries that may be related to their smoking regulations. Where we sampled smoking and nonsmoking areas, nicotine concentrations were significantly lower in nonsmoking areas. Conclusions Hospitality venues from European cities without smoking regulations have very high levels of SHS exposure. Monitoring of SHS on a regular basis as well as a total smoking ban in hospitality sector would be needed.

Hydrophilic interaction chromatography for the analysis of aminoglycosides.

The effect of mobile-phase constituents (pH and ionic strength) and chromatographic behaviour of ten aminoglycosides (streptomycin, dihydrostreptomycin, spectinomycin, apramycin, paramomycin, kanamycin A, gentamycin C1, gentamycin C2/C2a, gentamycin C1a and neomycin) in the bare silica, amino, amide and zwitterionic phases of hydrophilic interaction chromatography (HILIC) were studied systematically. Among the stationary phases studied, the zwitterionic phase provided the best separation of aminoglycosides. The effect of pH, ionic concentration and column temperature on retention time, peak shape and sensitivity was studied using a central composite design. pH affected sensitivity of the detection of analytes but not the retention time. High ionic strength in the mobile phase was necessary to control the ionic interactions between ionised aminoglycosides and the hydrophilic phase, thereby influencing peak shape and retention time. Column temperature affected sensitivity of the detection but not the retention time. During method development, crosstalk between the MS/MS channels of the analytes was observed and resolved.

Secondhand smoke in hospitals of Catalonia (Spain) before and after a comprehensive ban on smoking at the national level.

OBJECTIVE To assess changes in secondhand smoke exposure by means of airborne nicotine concentrations in public hospitals of Catalonia (Spain) before and after a comprehensive national smoking ban. METHODS We monitored vapor-phase nicotine concentrations in 44 public hospitals in Catalonia (Spain) before the smoking ban (September-December 2005) and one year after (September-December 2006). We installed 5-7 sampling devices per hospital for 7 days in different places (228 pairs of samples), and 198 pairs of samples were available for the final analysis. RESULTS The median nicotine concentration declined from 0.23 microg/m(3) (interquartile range: 0.13-0.63) before the law to 0.10 microg/m(3) (interquartile range: 0.02-0.19) after the law (% decline=56.5, p<0.01). We observed significant reductions in the median nicotine concentrations in all hospital locations, although secondhand smoke exposure was still present in some places (main hospital entrance, emergency department waiting rooms, fire escapes, and cafeterias). CONCLUSIONS Secondhand smoke in hospitals has decreased after the ban. Assessment of airborne nicotine concentrations appears to be an objective and feasible system to monitor and reinforce the compliance of smoke-free legislations in this setting.

A need for determination of arsenic species at low levels in cereal-based food and infant cereals. Validation of a method by IC-ICPMS.

The present study arose from the need to determine inorganic arsenic (iAs) at low levels in cereal-based food. Validated methods with a low limit of detection (LOD) are required to analyse these kinds of food. An analytical method for the determination of iAs, methylarsonic acid (MA) and dimethylarsinic acid (DMA) in cereal-based food and infant cereals is reported. The method was optimised and validated to achieve low LODs. Ion chromatography-inductively coupled plasma mass spectrometry (IC-ICPMS) was used for arsenic speciation. The main quality parameters were established. To expand the applicability of the method, different cereal products were analysed: bread, biscuits, breakfast cereals, wheat flour, corn snacks, pasta and infant cereals. The total and inorganic arsenic content of 29 cereal-based food samples ranged between 3.7-35.6 and 3.1-26.0 μg As kg(-1), respectively. The present method could be considered a valuable tool for assessing inorganic arsenic contents in cereal-based foods.

Determination of aminoglycoside residues in kidney and honey samples by hydrophilic interaction chromatography‐tandem mass spectrometry

Two methods based on liquid chromatography-tandem mass spectrometry were developed for the determination of ten aminoglycosides (streptomycin, dihydrostreptomycin, spectinomycin, apramycin, paromomycin, kanamycin A, gentamycin C1, gentamycin C2/C2a, gentamycin C1a, and neomycin B) in kidney samples from food-producing animals and in honey samples. The methods involved extraction with an aqueous solution (for the kidney samples) or sample dissolution in water (for the honey samples), solid-phase extraction with a weak cation exchange cartridge and injection of the eluate into a liquid chromatography-tandem mass spectrometry system. A zwitterionic hydrophilic interaction chromatography column was used for separation of aminoglycosides and a triple quadrupole mass analyzer was used for detection. The methods were validated according to Decision 2002/657/EC. The limits of quantitation ranged from 2 to 125 μg/kg in honey and 25 to 264 μg/kg in the kidney samples. Interday precision (RSD%) ranged from 6 to 26% in honey and 2 to 21% in kidney. Trueness, expressed as the percentage of error, ranged from 7 to 20% in honey and 1 to 11% in kidney.

Analysis of thyreostatic drugs in thyroid samples by ultra-performance liquid chromatography tandem mass spectrometry detection.

A method based on ultra-performance liquid chromatography-electrospray ionisation-tandem mass spectrometry for the determination of six thyreostatic drugs in thyroid tissue has been optimised and validated in accordance with the Decision 2002/657/EC. Samples are extracted with methanol and the extracts cleaned-up on silica cartridges. The recoveries range from 40% for 6-phenyl-2-thiouracil to 79% for 2-thiouracil. Quantification is carried out with blank tissue samples spiked with the analytes in the range 25-500 microg kg(-1). 5,6-Dimethyl-2-thiouracil is used as internal standard. CCalpha and CCbeta are in the ranges 4.3-16.1 microg kg(-1) and 8.7-20.7 microg kg(-1), respectively. Accuracy, expressed as percentage of error, is lower than 6% and relative standard deviation in reproducibility conditions falls between 5.6 and 10.3%. Nowadays, the proposed method is routinely implemented in the laboratory of the Agència de Salut Pública de Barcelona and allows processing of up to 20 samples per day.