Analysis and occurrence of 14 sulfonamide antibacterials and chloramphenicol in honey by solid-phase extraction followed by LC/MS/MS analysis

A method was developed for the analysis of 14 sulfonamide antibiotics and chloramphenicol in honey. These antibiotics have been banned for use in food-producing animals; yet, their residues were found in many samples, illustrating the need for a multiresidue analysis for these antibiotics in honey. The method described here uses an acid hydrolysis step to liberate the sugar-bound sulfonamides followed by a solid-phase extraction to remove potential interferences. Analysis was by liquid chromatography--electrospray ionization--tandem mass spectrometry in negative mode for all 15 analytes. This MRM method generated two structurally significant transitions per compound, and it was designed to conform to U.S. Food and Drug Administration MS confirmation guidelines. It also provides 4-EU identification points. One hundred sixteen samples from 25 countries were analyzed, and 38% were found to contain at least one target antimicrobial. Five different target compounds were found in honey from 13 different countries.

[Estimation of chloramphenicol in the working area air by high performance liquid chromatography]

Chloramphenicol (levomycetin) is a broad-spectrum antibiotic that is active against gram-positive and gram-negative microorganisms. At present, it is manufactured via organic synthesis. Working place air becomes polluted during the manufacture and use of medicines containing chloramphenicol. In the working place air, chloramphenicol is present as a disintegration aerosol and may provoke occupational diseases of varying severity in the exposed persons. A procedure has been determined to measure air chloramphenicol, by using high performance liquid chromatography. Aspiration through an AFA FPP-15 aerosol filter is a suitable device for air chloramphenicol sampling. The selected chloramphenicol is removed from the filter via triple methanol extraction in an ultrasound bath. The pooled extract is evaporated to dryness in a current of nitrogen and the dry residue is dissolved in the mobile phase containing acetonitrile : buffer (pH 4.8) = 30:70. The chloramphenicol determination procedure using reverse-phase liquid chromatography with ultraviolet detection at a wavelength of 275 nm has been developed and completely validated. Chromatographic conditions are given. The retention time of chloramphenicol is 6.5 min. The detection limit is 0.1 microg/cm3. The method is noted for a linear relationship between the concentration of chloramphenicol (microg/cm3) and the peak area (mm2) in the range of 1 to 20 microg/cm3.

Occurrences and ecological risks of roxithromycin, trimethoprim, and chloramphenicol in the Han River, Korea

We evaluated the occurrence of three antibiotics (roxithromycin, trimethoprim, and chloramphenicol) in surface water and effluents from several sewage treatment plants (STPs) on the Han River, Korea. In addition, standard acute toxicity tests were conducted using the microbe Vibrio fischeri, freshwater macroinvertebrates Daphnia magna and Moina macrocopa, and fish (Oryzias latipes) for these antibiotics. Antibiotics were more frequently detected at higher amounts in effluent samples and in samples collected during the low-flow season. For trimethoprim and chloramphenicol, the levels observed in surface water during low flow were, on average, 108 and 31 ng/L, respectively. These levels were comparable to those measured in the municipal effluents (average, 80 and 37 ng/L, respectively), suggesting the presence of other sources upstream (e.g., livestock wastes). For roxithromycin, surface water levels were approximately an order of magnitude lower than effluent levels. Adverse effects of roxithromycin, trimethoprim, and chloramphenicol were observed at mg/L levels in standard acute aquatic ecotoxicity tests. Based on hazard quotients calculated for the three antibiotics, minimal risks to aquatic systems are suggested. To further increase scientific understanding about the potential impacts of these pharmaceuticals in the environment, however, chronic ecotoxicology studies, with more subtle but ecologically meaningful end points or in combination with other mechanistically related contaminants, may be beneficial.

[Analysis of chloramphenicol in propolis extract by LC/MS/MS]

A quantitative analysis method using LC/MS/MS of chloramphenicol (CAP) in propolis extract (ethanol extract) has been established. Extraction of CAP from propolis extract was performed by adding water, followed by salting-out with sodium chloride. Through this procedure, the wax components of propolis extract could be effectively removed. LC separation was performed with a reverse-phase column (Mightysil RP-18 GP Aqua, 2.0 mm x 150 mm, 5 microm), using 10 mmol/L of ammonium acetate-acetonitrile (75 : 25) as a mobile phase. The flow rate was 0.2 mL/min. Ionization was performed by electrospray ionization (ESI) in the negative mode. The detection and quantification limits of CAP in propolis extract were 0.05 and 0.15 ng/g, respectively, and the recovery rate (spiked CAP level was 0.5 ng/g) was 111.2%. When eight samples of propolis extract products on the market were analyzed using this method, CAP was not detected (N.D.) in any of the samples.

Multiresidue determination of fluoroquinolone, sulfonamide, trimethoprim, and chloramphenicol antibiotics in urban waters in China

A feasible method has been optimized to simultaneously determine multiclass antibiotic residues, including sulfonamides, fluoroquinolones, trimethoprim, and chloramphenicol in urban riverine water and wastewater by off-line solid phase extraction and high-performance liquid chromatography coupled with a diode-array ultraviolet detector and a fluorescence detector. Internal standard and standard addition methods were used in combination to identify and quantify these antibiotics to compensate for the matrix interference. The method quantification limits (MQLs) were determined to be 0.035 to 0.100 microg/L and 0.100 to 0.300 microg/L for the riverine water and wastewater, respectively. Recoveries of the investigated antibiotics ranged from 63 to 126%. Sulfamethoxazole was the most frequently detected antibiotic residue in Guangzhou section of the Major Pearl River, South China, with a maximum level of 0.510 microg/L. Fluoroquinolone antibiotics were relatively less detected with a maximum level of 0.459 microg/L. The maximum concentration of sulfamethoxazole reached 5.597 microg/L in the raw wastewater from a large-scale sewage treatment plant in Guangzhou city. Around 30% of sulfamethoxazole might survive the primary clarification and biotreatment processes in the sewage treatment plant. None of the investigated antibiotics have been found above MQLs in the final effluent after chlorine disinfection.

Optimization and validation of capillary electrophoretic method for the analysis of amphenicols in poultry tissues

A simple, rapid capillary electrophoretic (CE) method for simultaneous analysis of three amphenicols (chloramphenicol, thiamphenicol and florfenicol) in poultry tissues has been developed and validated. The separation condition were: buffer solution composed with 25 mM sodium tetraborate decahydrate and 10 mM sodium dodecylsulfate, an uncoated fused-silica capillary (57 cm x 75 microm i.d.), voltage 20 kV, and temperature 22 degrees C. The method involved simple deproteinization by acetonitrile and SPE extraction procedure. The analytical method was validated according to the FDA bioanalytical method guidance. The method was linear (r > 0.999) at concentrations ranging from: 0.005 - 1 for chloramphenicol, 0.01 - 1 for thiamphenicol, and 0.025 - 5 microg/g for florfenicol. The precision values were less than 9.8 for intra- and 14.8% for inter-day variability, and accuracies ranged from 92.0 to 106.0% for analyzed amphenicols. The overall recoveries of all antibiotics from tissue samples were above 82.2%. Some new parameters were calculated as limit of decision (CCalpha) and detection capability (CCbeta). The CE method is simple and reliable for simultaneous determination of residues of chloramphenicol, thiamphenicol and florfenicol in muscle with a total run time of less than 7 min.

Stress-activated bioluminescent Escherichia coli sensors for antimicrobial agents detection

A DNA cartridge encoding Photinus pyralis luciferase (luc), lacZ homology extensions and an excisable marker was constructed to facilitate the conversion of Escherichia coli lacZ fusions to luc fusions by lambda Red-mediated recombination. This tool was used to transform a cspA::lacZ strain into a luminescent biosensor for C-group translational inhibitors. Comparison of cspA::lacZ and cspA::luc cells showed native firefly luciferase to be a more rapid and sensitive reporter than beta-galactosidase for chloramphenicol detection. To evaluate the usefulness of a red-shifted variant of P. pyralis luciferase (LucR1) for biosensor development, a single copy translational fusion between the SOS-inducible sulA promoter and the lucR1 gene was inserted at the malP site of the E. coli chromosome. The sulA::lucR1 fusion allowed high signal detection of the quinolone ofloxacin to levels as low as 15% of the minimum inhibitory concentration and could be combined with a cspA::lacZ fusion to yield a biosensor suitable for the independent and dual detection of chloramphenicol and ofloxacin.

Development of an improved method for trace analysis of chloramphenicol using molecularly imprinted polymers

A confirmatory method is described for the determination of the illegal antibiotic chloramphenicol using a specifically developed molecularly imprinted polymer (MIP) as the sample clean-up technique. The newly developed MIP was produced using an analogue to chloramphenicol as the template molecule. Using an analogue of the analyte as the template avoids a major traditional drawback associated with MIPs of residual template leeching or bleeding. The MIP described was used as a solid-phase extraction phase for the extraction of chloramphenicol from various sample matrices including honey, urine, milk and plasma. A full analytical method with quantification by LC-MS/MS is described. The method was fully validated according to the European Union (EU) criteria for the analysis of veterinary drug residues.

[Simultaneous determination of seven sulfonamides and metronidazole and chloramphenicol in cosmetics by high performance liquid chromatography]

A method for the simultaneous determination of seven sulfonamides (sulfacetamide, sulfapyridine, sulfamerazine, sulfamethazine, sulfamater, sulfamonomethoxine, sulfamethoxazole) and metronidazole, chloramphenicol in cosmetics has been developed by high performance liquid chromatography with a photodiode array detector (HPLC-PDA). The chromatographic column Atlantis dC18 (150 mm x 4.6 mm, 5 microm) was used with acetonitrile-0.1% formic acid (2:8, v/v) aqueous solution as mobile phase at a flow rate of 1.0 mL/min. Samples were extracted by mobile phase and detected by HPLC-PDA at 268 nm. The limits of quantification were 3 - 80 microg/g. The correlation coefficients of linear calibration curves were over 0. 999 3 within the sulfonamide concentration range of 20 - 200 microg/mL and metronidazole and chloramphenicol concentration range of 40 - 400 microg/mL. Average recoveries were 83.8% - 105.3% at the spiked levels of 50 microg/mL and 150 microg/mL for sulfonamides, and 100 microg/mL and 300 microg/mL for metronidazole and chloramphenicol. The relative standard deviations were below 5%. This method can be routinely used for the determination of seven sulfonamides and metronidazole, chloramphenicol in cosmetics.

Sensitive voltammetric determination of chloramphenicol by using single-wall carbon nanotube–gold nanoparticle–ionic liquid composite film modified glassy carbon electrodes

A novel composite film modified glassy carbon electrode has been fabricated and characterized by scanning electron microscope (SEM) and voltammetry. The composite film comprises of single-wall carbon nanotube (SWNT), gold nanoparticle (GNP) and ionic liquid (i.e. 1-octyl-3-methylimidazolium hexafluorophosphate), thus has the characteristics of them. The resulting electrode shows good stability, high accumulation efficiency and strong promotion to electron transfer. On it, chloramphenicol can produce a sensitive cathodic peak at -0.66 V (versus SCE) in pH 7.0 phosphate buffer solutions. Parameters influencing the voltammetric response of chloramphenicol are optimized, which include the composition of the film and the operation conditions. Under the optimized conditions, the peak current is linear to chloramphenicol concentration in the range of 1.0x10(-8)-6.0x10(-6) M, and the detection limit is estimated to be 5.0x10(-9) M after an accumulation for 150 s on open circuit. The electrode is applied to the determination of chloramphenicol in milk samples, and the recoveries for the standards added are 97.0% and 100.3%. In addition, the electrochemical reaction of chloramphenicol and the effect of single-wall carbon nanotube, gold nanoparticle and ionic liquid are discussed.

Molecularly imprinted polymer microspheres for solid-phase extraction of chloramphenicol residues in foods

Preparation of molecularly imprinted polymer microspheres (MIPMs) for chloramphenicol (CAP) by aqueous suspension polymerization is reported for the first time in this study. The resulting MIPMs had the ability to specifically adsorb CAP, and the molecularly imprinted solid phase extraction (MISPE) based on the MIPMs was shown to be applicable for clean-up and preconcentration of trace CAP in milk and shrimp samples with high recoveries of 92.7% and 84.9%, respectively. Combined with MISPE, the conventional HPLC-UV analysis sensitivity for CAP in foods could be significantly increased.

Determination of selected antibiotics in the Victoria Harbour and the Pearl River, South China using high-performance liquid chromatography-electrospray ionization tandem mass spectrometry

Nine selected antibiotics in the Victoria Harbour of Hong Kong and the Pearl River at Guangzhou, South China, were analyzed using high-performance liquid chromatography-electrospray ionization tandem mass spectrometry. The results showed that the concentrations of antibiotics were mainly below the limit of quantification (LOQ) in the marine water of Victoria Harbour. However, except for amoxicillin, all of the antibiotics were detected in the Pearl River during high and low water seasons with the median concentrations ranging from 11 to 67 ng/L, and from 66 to 460 ng/L, respectively; and the concentrations in early spring were about 2-15 times higher than that in summer with clearer diurnal variations. It was suggested that the concentrations of antibiotics in the high water season were more affected by wastewater production cycles due to quick refreshing rate, while those in the low water season may be more sensitive to the water column dynamics controlled by tidal processes in the river.

[Determination of chloropromazine residues in animals kidney and urine using LC-MS/MS method]

Chloropromazina (CP) is subjected to monitoring food animals products, with a minimum required performance limit (MPRL) set 5.0 microg/kg. Homogenized kidney and urine were extracted with acetonitrile. CP- d3 was used as internal standard. LC separation was done on Luna C18 150 x 2 mm, 5 microm column in mobile phase acetonitrile-acetic acid. CP was determination by LC-ESI-MS/MS negative mode. The method was validation according to the criteria of Decision Commission No 2002/657/EC. Recoveries for the level 5.0 ng/g were in the range 84-102%. The limit of decision (CCalpha) and detection capability (CCbeta) CP in kidney were 1.19; 2.87 ng/g and urine 1.08; 2.61 ng/g.

Chloramphenicol extraction from honey, milk, and eggs using polymer monolith microextraction followed by liquid chromatography-mass spectrometry determination

A rapid confirmatory method for monitoring chloramphenicol (CAP) residues in honey, whole milk, and eggs is presented. This method is based on the polymer monolith microextraction (PMME) technique and high-performance liquid chromatography (HPLC)-electrospray ionization mass spectrometry (MS). A poly(methacrylic acid-ethylene glycol dimethacrylate) monolithic capillary column was selected as the extraction medium. To obtain optimum extraction efficiency, several parameters related to PMME were investigated. After dissolution in 20 mM phosphate solution at pH 4.0 and centrifugation, honey, eggs, or milk samples were directly passed through the extraction tube. The LC-MS instrument was equipped with an electrospray ion source and a single quadrupole. The eluates were analyzed by LC-MS in the negative-ion mode and by monitoring a pair of isotopic ions for the target compound. The in-source collision-induced dissociation process produced confirmatory ions. The recoveries of CAP from real samples spiked at 0.1-10 ng/g (honey), 0.2-10 ng/mL (milk), and 0.2-10 ng/g (egg) were in the range of 85-102%, with relative standard deviations ranging between 2.1% and 8.9%. The limits of detection (S/N = 3) were 0.02 ng/g, 0.04 ng/mL, and 0.04 ng/g in honey, milk, and eggs, respectively. The proposed method was proved to be robust in monitoring CAP residue in honey, milk, and eggs.

A preliminary study on the occurrence and behavior of sulfonamides, ofloxacin and chloramphenicol antimicrobials in wastewaters of two sewage treatment plants in Guangzhou, China

Wastewater samples collected from two sewage treatment plants (STPs) in Guangzhou, China were acidified, solid-phase extracted (SPE) with Oasis HLB cartridges, followed by instrumental measurement by high performance liquid chromatography (HPLC) coupled with a diode array UV detector (DAD) and a fluorescence detector (FLD) for the occurrence and fate of antimicrobial compounds sulfadiazine (SDZ), sulfamethoxazole (SMX), ofloxacin (OFX) and chloramphenicol (CAP). Antimicrobials have been detected at 5.10-5.15, 5.45-7.91, 3.52-5.56 and 1.73-2.43 microg L(-1) for SDZ, SMX, OFX and CAP in the raw sewages of the two STPs, respectively. The concentrations of antimicrobials do not show substantial changes after preliminary mechanical sedimentation. No quantifiable sulfonamides and chloramphenicol have been identified, and >85% of ofloxacin has been removed in the effluents after activated sludge treatment in the two STPs, indicating that activated sludge treatment is effective and necessary to remove antimicrobial substances in municipal sewage.

Determination of chloramphenicol residues in crustaceans: Preparation and evaluation of a proficiency test in Germany

Chloramphenicol (CAP) is banned for use in food-producing animals and is, thus, controlled on the basis of the National Residue Control Plans in the European Union. Due to current problems with residues of CAP in shrimp, crayfish and prawns, a sensitive GC/NCI/MS method was optimised and in-house validated. The validation study resulted in a decision limit (CCalpha) of 0.07 microg kg-1, a recovery of 95% and a within-laboratory reproducibility of 9%. The method was used for preparing a proficiency test to assess the quality of residue control in Germany. The proficiency test involved analysis of five samples and the results were very satisfactory. The reproducibility standard deviation for five samples ranged from 17 to 24%, and the median concentrations lay between 0.43 and 0.51 microg kg-1 CAP. These values are clearly below the corresponding Horwitz standard deviation of about 50%. From the study, it can be concluded that there are, irrespective of the method applied, well-established and proper working analytical procedures for the control of CAP around the minimum required performance limit (MRPL) of 0.3 microg kg-1.

A linear modulation-based stochastic resonance algorithm applied to the detection of weak chromatographic peaks

A simple stochastic resonance algorithm based on linear modulation was developed to amplify and detect weak chromatographic peaks. The output chromatographic peak is often distorted when using the traditional stochastic resonance algorithm due to the presence of high levels of noise. In the new algorithm, a linear modulated double-well potential is introduced to correct for the distortion of the output peak. Method parameter selection is convenient and intuitive for linear modulation. In order to achieve a better signal-to-noise ratio for the output signal, the performance of two-layer stochastic resonance was evaluated by comparing it with wavelet-based stochastic resonance. The proposed algorithm was applied to the quantitative analysis of dimethyl sulfide and the determination of chloramphenicol residues in milk, and the good linearity of the method demonstrated that it is an effective tool for detecting weak chromatographic peaks.

Simple determination of betamethasone and chloramphenicol in a pharmaceutical preparation using a short monolithic column coupled to a sequential injection system

This contribution describes the use of a new separation method based on a reversed-phase sequential injection chromatography (SIC) technique for simultaneous determination of chloramphenicol and betamethasone in pharmaceutical eye drops. A short monolithic column coupled with a sequential injection analysis (SIA) system enabled separation of two compounds in one step. A Chromolith Flash RP-18e, 25 x 4.6 mm column with a 5 mm precolumn (Merck, Germany) and a FIA1ab 3000 system (USA) with a 6-port selection valve and 5 mL syringe were used for sequential injection chromatographic separations in this study. The mobile phase used was acetonitrile-water (30:80, v/v), flow rate 0.48 mL/min; UV detection was at two wavelengths, i.e., 241 and 278 nm (absorption maxima of betamethasone and chloramphenicol, respectively). The basic validation parameters showed good results: linearity of determination for both compounds including internal standard (propylparaben) >0.999; repeatability of determination (RSD) in the range 0.8-1.7% at two different concentration levels, and detection limits in the range 0.5-1.0 mg/mL. The chromatographic resolution between compound peaks was greater than 2.1 and the analysis time was less than 8 min under optimal conditions. The developed sequential injection chromatography method was compared with the HPLC method and was found to be applicable for routine analysis of active compounds in pharmaceutical preparations.

Stability of chloramphenicol residues in shrimp subjected to heat processing treatments

The stability of chloramphenicol residues in white shrimp (Penaeus indicus) subjected to cooking (100 degrees C) for 10, 20 and 30 min (C1, C2 and C3) as well as retorting (121 degrees C) for 10 and 15 min (R1 and R2) was studied by a microbial assay method using Photobacterium leiognathi as the test organism. The microbial assay method was found to have a good sensitivity of 1 microg/ml the loss of chloramphenicol in shrimp subjected to cooking for 10, 20 and 30 min was 6%, 12% and 29%, respectively. Similarly, the loss was 9% and 16% from the shrimp subjected to retorting for 10 and 15 min, respectively. The loss of chloramphenicol was found to increase with increase in temperature and duration of heating. This study showed that chloramphenicol is an unstable aquaculture drug that is destroyed or degrades during heat processing treatments.

Small molecule microarrays for drug residue detection in foodstuffs

Microarrays have been used as tools for analyzing biological compositions at different levels. In this study, we proposed a small molecule microarray (SMM) method for detection of three veterinary drug residues, chloramphenicol, clenbuterol, and tylosin, in foodstuffs simultaneously and quantitatively. The small drug molecules were immobilized on the surface of the modified glass slides. Then the mixture of drug corresponding antibodies and standards or samples was added to the reaction area. After incubation, the antigen-antibody binding was detected using cy5 labeled secondary antibody. The calibration curves of the residues were drawn, and they indicated the lowest detection limit the linearity range. The detectable concentrations of the three residues are lower than the maximum residue levels (MRLs). No cross reactivity was found among the three residues. The coefficient of variation of the spot intensities was below 5% in a subarray, and below 15% among subarrays. The spike sample test and the comparison of detection results by SMMs and ELISA demonstrated the accuracy of the proposed SMMs method.

Determination of chloramphenicol in royal jelly by liquid chromatography/tandem mass spectrometry

A liquid chromatographic/tandem mass spectrometric method was developed and validated for the determination of chloramphenicol (CAP) in royal jelly. Royal jelly samples were first denatured with lead acetate solution, and the CAP was extracted with solid-phase extraction before separation by liquid chromatography. A triple-quadrupole mass spectrometer operated in the negative electrospray ionization and selected-reaction monitoring mode was used for the detection of CAP. For method validation, royal jelly samples were fortified at CAP levels between 0.1 and 10.0 microg/kg; at these levels, recovery values (internal standard-corrected) ranged from 93.3 to 105.0%, and the within-laboratory reproducibility (relative standard deviation) was < or = 9.1%. The decision limit was 0.07 microg/kg, and the detection capability was 0.1 microg/kg.

Development of a chemiluminescent ELISA for determining chloramphenicol in chicken muscle

An indirect competitive enzyme-linked immunosorbent assay (ELISA) with chemiluminescent (CL) detection for chloramphenicol (CAP) in chicken muscle was developed. CAP-specific polyclonal antibody was raised in rabbit with a CAP-succinate derivative conjugated with bovine serum albumin. Luminol solution was used as the substrate of horseradish peroxidase. The detection limit was 6 ng/L. The CL-ELISA was 10 times more sensitive compared to the colorimetric-ELISA. When CAP was spiked in chicken muscle at levels of 0.05-5 microg/kg, recoveries ranged from 97 to 118% with coefficients of variation of 6-22%. In an actual residue study, the results obtained by CL-ELISA correlated well with those obtained by gas chromatography with microcell electron capture detector. The residue levels of CAP in treated chicken decreased with time and dropped rapidly after the first 6 h from around 50 to 10 microg/kg. After 3 days, CAP was not detected in chicken muscle. The developed method is therefore suitable for screening of CAP in chicken muscle samples.

[Analysis of chloramphenicol in honey and royal jelly by LC/MS/MS]

A sensitive and selective method using liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) was developed for the determination of chloramphenicol (CAP) in honey and royal jelly. Mass spectral acquisition was performed in the negative mode by applying multiple reaction monitoring. In LC separation, Mightyl RP-18GP and 10 mmol/L ammonium acetate-acetonitrile were used as the column and mobile phase, respectively. CAP in honey samples was diluted with water, while CAP in royal jelly was extracted with 1% metaphosphoric acid-methanol (4 : 6). The solutions were cleaned up with an Oasis HLB cartridge. The quantification limits of CAP in honey and royal jelly were 0.3 ng/g and 1.5 ng/g, respectively. The recoveries of CAP from both honey and royal jelly at the quantification limits were over 92%. Twenty honey products and seven royal jelly products were analyzed by the developed method. CAP was detected in one honey product at 0.6 ng/g and in six royal jelly products at the level of 1.5-17.8 ng/g. These results show that the developed method has satisfactory sensitivity selectivity and is useful for the determination of CAP residues in honey and royal jelly.

Determination of chloramphenicol residues in meat, seafood, egg, honey, milk, plasma and urine with liquid chromatography–tandem mass spectrometry, and the validation of the method based on 2002/657/EC

A simple and rapid method for the determination and confirmation of chloramphenicol in several food matrices with LC-MS/MS was developed. Following addition of d5-chloramphenicol as internal standard, meat, seafood, egg, honey and milk samples were extracted with acetonitrile. Chloroform was then added to remove water. After evaporation, the residues were reconstituted in methanol/water (3+4) before injection. The urine and plasma samples were after addition of internal standard applied to a Chem Elut extraction cartridge, eluted with ethyl acetate, and hexane washed. Also these samples were reconstituted in methanol/water (3+4) after evaporation. By using an MRM acquisition method in negative ionization mode, the transitions 321-->152, 321-->194 and 326-->157 were used for quantification, confirmation and internal standard, respectively. Quantification of chloramphenicol positive samples regardless of matrix could be achieved with a common water based calibration curve. The validation of the method was based on EU-decision 2002/657 and different ways of calculating CCalpha and CCbeta were evaluated. The common CCalpha and CCbeta for all matrices were 0.02 and 0.04 microg/kg for the 321-->152 ion transition, and 0.02 and 0.03 microg/kg for the 321-->194 ion transition. At fortification level 0.1 microg/kg the within-laboratory reproducibility is below 25%.