Determination Of Sulfonamides In Milk Research Articles

Automated centrifugation-less milk deproteinization and homogenous liquid-liquid extraction of sulfonamides for online liquid chromatography

A novel approach to the determination of sulfonamides in milk based on the Lab-In-Syringe technique is presented. The method involves automated salting-out liquid-liquid extraction of the analytes, allowing simultaneous sample deproteination without requiring centrifugation or manual sample handling. The procedural parameters, including salt type, solvent-to-sample ratio, and salt solution volume, were studied. The extracts obtained were diluted in situ and transferred to online coupled liquid chromatography for analyte separation carried out in parallel to the subsequent extraction. In this way, a sample throughput of approximately 6 h−1 was achieved. The detection limits ranged from 25 to 32 μg L−1 using a 500 μL milk sample and spectrophotometric detection. The applicability of the developed method to sample analysis was proven by recovery values ranging from 73.2% to 94.1% (86.3% on average) for milk samples of different fat content spiked at 3 μg mL−1 level. Straightforward automation of one of the most laborious preparation steps in food analysis, i.e., deproteination, was demonstrated.

Determination of sulfonamides in milk and egg samples by HPLC with mesoporous polymelamine-formaldehyde as magnetic solid-phase extraction adsorbent.

In this work, magnetic mesoporous polymelamine-formaldehyde composites were synthesized via a facile Schiff base reaction. The magnetic mesoporous polymelamine-formaldehyde composites combined both the properties of mesoporous polymelamine-formaldehyde and the magnetism of NH2 -SiO2 @Fe3 O4 nanoparticles, possessing high specific surface area (150.66 m2 g-1 ) and good magnetism (24.50 emu g-1 ). The magnetic mesoporous polymelamine-formaldehyde composites were employed as magnetic adsorbent for the extraction of sulfonamides. Under optimal conditions, good linearities with correlation coefficients higher than 0.9984 were obtained between peak area and sulfonamides concentration (2-200 μg L-1 ) with limits of detection in the range of 0.33-0.58 μg L-1 . The established method was successfully applied for the determination of sulfonamides in egg and milk samples. The adsorption mechanisms demonstrated that the adsorption of magnetic mesoporous polymelamine-formaldehyde composites toward sulfonamides was a multilayer process, and adsorption kinetics followed the pseudo-second-order model.

Covalent organic framework Schiff base network-1-based pipette tip solid phase extraction of sulfonamides from milk and honey

In this work, a covalent organic framework Schiff base network-1 (SNW-1), was synthesized based on the Schiff base reaction between terephthalaldehyde and melamine and characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction and nitrogen adsorption-desorption isotherm analyses. The prepared SNW-1 was employed as pipette tip solid phase extraction adsorbent for the extraction of sulfonamides (SAs) prior to high performance liquid chromatography analysis. The parameters affecting the extraction efficiency, including the salt concentration, sample pH, amount of adsorbent, and types and volume of eluent were investigated in detail. Good linearities were obtained between the peak area and SAs concentration ranging from 5 to 500 ng mL−1 with correlation coefficients (R2) higher than 0.9998. The limits of detection and RSDs were lower than 0.25 ng mL−1 and 1.9 %, respectively. The developed method was further applied for the determination of SAs in milk and honey samples with recoveries in the range of 85.8 % – 118.0 % and RSDs less than 9.5 %. The results demonstrate that the SNW-1 shows great potential for the enrichment of trace SAs in complex matrices.

Determination of Sulfonamides in Milk by Cloud Point-Salting Out Extraction and Ultra-High-Performance Liquid Chromatography Tandem Mass Spectrometry.

A method involving cloud point-salting out extraction (CPSOE) coupled with UHPLC-MS/MS was developed for the determination of eleven sulfonamides in milk. In this study, the type and concentration of the surfactant, de-emulsification condition, pH value, volume of n-butanol, equilibration temperature and time were optimized. For this developed method, the linear range of SAs was from 0.05 to 50 μg L-1, and the correlation coefficients were higher than 0.997. The average recoveries for SAs were from 61.32 to 91.67%, and the LOQs were less than 0.06 μg kg-1.

Simultaneous determination of sulfonamides in milk: In-situ magnetic ionic liquid dispersive liquid-liquid microextraction coupled with HPLC.

Four novel organic magnetic ionic liquids were synthesized and characterized. A new method of in-situ magnetic ionic liquid dispersive liquid-liquid microextraction coupled with HPLC was established to simultaneously separate, preconcentrate and determine trace amount of sulfonamides in milk samples for the first time. In this work, extraction procedure was free of volatile organic solvent. Extraction equilibrium was immediately achieved without further operation such as vortex shaking. Magnetic separation of two phases was effectively achieved by applying external magnetic field without need of centrifugation. Furthermore, only a very small amount of inorganic salts were generated. This is the first time to realize all these advantages in an analytical method. Under the optimal conditions, satisfactory enrichment factors, precisions, linear range and low limit of detection and quantitation were acquired. The validated method was successfully applied in the simultaneous analysis of 5 sulfonamides in real milk samples.

Fe3 O4 /reduced graphene oxide-carbon nanotubes composite for the magnetic solid-phase extraction and HPLC determination of sulfonamides in milk.

A novel magnetic adsorbent Fe3 O4 /reduced graphene oxide-carbon nanotubes, was prepared by one-pot solvothermal synthesis method. It was characterized by scanning electron microscopy, X-ray powder diffraction and vibrating sample magnetometry. The diameter of Fe3 O4 microparticles was about 350nm, which were covered by carbon nanotubes and reduced graphene oxide sheets, while carbon nanotubes inserted between the reduced graphene oxide sheets effectively prevented their aggregation. The composite had large surface area and good magnetic property, suiting for magnetic solid-phase extraction and the determination of sulfonamides, by coupling with high-performance liquid chromatography. Under the optimized conditions (including extraction time, amount of adsorbent, solution pH, ionic strength and desorption conditions), a good linear was achieved in the concentration range of 5-500 μg/L and the low limits of detection and low limits of quantification were 0.35-1.32 and 1.16-4.40 μg/L, respectively. The enrichment factors were estimated to be 24.72 to 30.15 fold. The proposed method was applied for the detection of sulfonamides in milk sample and the recoveries were 88.4-105.9%, with relative standard deviations of 0.74-5.38%.

Determination of sulfonamides in milk by ID-LC-MS/MS

Determination of sulfonamides in milk by ID-LC-MS/MS

Determination of sulfonamides in milk by capillary electrophoresis with PEG@MoS2 as a dispersive solid-phase extraction sorbent.

A synthetic polyethylene glycol-molybdenum disulfide (PEG@MoS2) composite was prepared using a simple method, and the application of this material in dispersive solid-phase extraction (DSPE) was investigated for the enrichment of eight sulfonamides (SAs) in milk samples. The composite was characterized by energy dispersive spectroscopy, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and Brunauer–Emmett–Teller measurements. The results showed that the MoS2 synthesized in the presence of PEG has the advantage of a larger surface area and that the adsorption effect of this MoS2 was enhanced. After extraction, the eight SAs were separated by capillary zone electrophoresis with a good linear relationship (R2 > 0.9902) in the range of 0.3–30 µg ml−1 and good precision (between 0.32% and 9.83%). Additionally, good recoveries (between 60.52% and 110.91%) were obtained for the SAs in the milk samples. The developed PEG@MoS2-based DSPE method could be applied for the enrichment of SAs in real milk samples.

Graphene-functionalized melamine sponges for microextraction of sulfonamides from food and environmental samples

The study describes the functionalization of melamine sponges with graphene and its use as an adsorbent for the microextraction of sulfonamides from food and environmental samples. The graphene-functionalized melamine sponge (GMeS) was prepared by an easy, one-step procedure, which complies with the principles of green chemistry and is proved advantageous over previously described methods. The applicability of the GMeS in extraction procedures was studied and an analytical method for the determination of sulfonamides in milk, eggs and lake water was developed and validated according to SANCO/12571/2013 guideline. The developed method was highly accurate and reproducible, while the limits of quantification were found to be relatively low (0.31–0.91μgkg−1, 0.96–1.32μgkg−1 and 0.10–0.29μgL−1 in the case of milk, eggs and lake water respectively). Furthermore, matrix effects were absent in all cases, since the microextraction procedure serves also as a clean-up step. The low cost of synthesis, the environmentally friendly conditions, the efficiency and high extraction recoveries are some additional advantages of the proposed procedure. To the best of our knowledge, this is the first time that a GMeS is prepared in a straightforward way and used for analytical purposes.

Trends in Microextraction-Based Methods for the Determination of Sulfonamides in Milk

Sulfonamides (SAs) represent a significant category of pharmaceutical compounds due to their effective antimicrobial characteristics. SAs were the first antibiotics to be used in clinical medicine to treat a majority of diseases, since the 1900s. In the dairy farming industry, sulfa drugs are administered to prevent infection, in several countries. This increases the possibility that residual drugs could pass through milk consumption even at low levels. These traces of SAs will be detected and quantified in milk. Therefore, microextraction techniques must be developed to quantify antibiotic residues, taking into consideration the terms of Green Analytical Chemistry as well.

Alternative sample treatments for the determination of sulfonamides in milk by HPLC with fluorescence detection

This paper presents two sample treatments, dispersive liquid–liquid microextraction (DLLME) and QuEChERS for the determination of 9 sulfonamides, regulated by the EU Council in milk samples. Both methods represent useful alternatives to conventional procedures based mainly in solid-phase extraction, in terms of simplicity, reduction of organic solvents, sample throughput and effectiveness for cleaning-up complex samples. They have been evaluated and compared in terms of efficiency, trueness, sensitivity and precision, using HPLC with fluorescence detection employing a previous derivatisation step with fluorescamine. Clean extracts were obtained with recoveries between 90.8–104.7% and 83.6–104.8% for DLLME and QuEChERS, respectively. Matrix-matched calibration curves were established for both methods using milk samples spiked at four concentration levels. LODs (3xS/N) lower than 1.21μgL−1 and 2.73μgL−1 for DLLME and QuEChERS, respectively, were obtained in all cases. The precision, in terms of repeatability and intermediate precision, was lower than 10% in all cases.

C18-coated stir bar sorptive extraction combined with high performance liquid chromatography–electrospray tandem mass spectrometry for the analysis of sulfonamides in milk and milk powder

A simple, rapid, sensitive, inexpensive and less sample consuming method of C18-stir bar sorptive extraction (SBSE)–high performance liquid chromatography (HPLC)–tandem mass spectrometry (MS/MS) was proposed for the determination of six sulfonamides in milk and milk powder samples. C18 silica particles coated stir bar was prepared by adhesion method, and two kinds of adhesive glue, polydimethylsiloxane (PDMS) sol and epoxy glue were tried. It was found that the C18-coated stir bar prepared by PDMS sol as adhesive glue is more robust than that prepared by epoxy glue when liquid desorption was employed, in terms of both lifetime and organic solvent tolerance. The preparation of C18 stir bar was simple with good mechanic strength and the stir bar could be reused for more than 20 times. Granular coating has relatively high specific surface area and is propitious to sorptive extraction based process. Compared to conventional PDMS SBSE coating, C18 coating shows good affinity to the target polar/weak polar sulfonamides. To achieve optimum SBSE extraction performance, several parameters including extraction and desorption time, ionic strength, sample pH and stirring speed were investigated. The detection limits of the proposed method for six sulfonamides were in the range of 0.9–10.5μg/L for milk and 2.7–31.5μg/kg for milk powder. Good linearities were obtained for sulfonamides with the correlation coefficients (R) above 0.9922. Finally, the proposed method was successfully applied to the determination of sulfonamides in milk and milk powder samples and satisfied recoveries of spiked target compounds in real samples were obtained.

Optimization of a solid-phase extraction procedure in the fluorimetric determination of sulfonamides in milk using the second-order advantage of PARAFAC and D-optimal design

The objective of this work is to optimize a solid-phase extraction procedure for the simultaneous determination of sulfadiazine, sulfamerazine, and sulfamethazine in milk by fluorimetric detection. For this task, an alternative strategy is employed, which allows one to reduce noticeably the number of experiments without losing the quality of the estimations. It consists of the use of a D-optimal design together with PARAFAC decomposition for the calculation of the response in the experimental design. Effects of amount of cartridge sorbent, kind of milk, volume of conditioning solutions, kind of wash and elution, and kind of mixture of sulfonamides have been evaluated, for maximizing sulfonamide mean recovery and minimizing its standard deviation. Since milk without sulfonamides may give some matrix effect over the fluorescence signal, its behavior has also been studied. Optimal conditions have been selected where the ratio between sulfonamide recovery and milk without sulfonamides was the highest, which are 500 mg of cartridge sorbent, acid wash, and elution and 3 mL of conditioning solutions. The type of milk and mixture of sulfonamides not significant. This makes the procedure suitable for the combined determination of sulfadiazine, sulfamerazine, and sulfamethazine in any kind of milk. Finally, an experimental procedure is proposed, obtaining a sulfonamide mean recovery equal to 68.5% with values of standard deviation between 7 and 8 microg kg(-1).

How to search the experimental conditions that improve a Partial Least Squares calibration model: Application to a flow system with electrochemical detection for the determination of sulfonamides in milk

This paper deals with the selection of experimental conditions and how the signals obtained in these conditions influence the fitted Partial Least Squares calibration model. The multivariate signals come from a flow analysis system with amperometric detection when determining sulfadiazine, sulfamerazine and sulfamethazine in milk. The solution (carrier plus analyte) was pumped through the system to provide a continuous supply of analyte to the cell. The detector was programmed for a scan mode operation being the multivariate signal the hydrodynamic voltammogram. To obtain an analytical signal of enough analytical quality, the Net Analyte Signal and its standard deviation have been optimised by using an experimental design. The conflicting behaviour of the two responses has been solved by estimating the Pareto-optimal front. The multivariate signals recorded in the optimal conditions found have been calibrated by Partial Least Squares regression and their figures of merit validated according to the criteria established in European Decision 2002/657/EC. In relation to the permitted limit, 100 µg l − 1 in milk, for the total content of sulfonamides established in the Commission Regulation EC no. 281/96 the proposed method has a decision limit of 109.1 µg l − 1 and the capability of detection is 117.9 µg l − 1 for both probability of false non-compliance and of false compliance equal to 5%. A recovery of 86.5% ± 2.4% ( n = 5) has been obtained.

Determination of sulfonamides in milk after precolumn derivatisation by micellar liquid chromatography

A simple method to identify and determine six sulfonamides (sodium sulfacetamide, sulfamethizole, sulfaguanidine, sulfamerazine, sulfathiazole and sulfamethoxazole) in milk by micellar liquid chromatography (MLC) is reported. The assay makes use of a precolumn diazotisation-coupling derivatisation including the formation of an azo dye that can be detected at 490 nm. Furthermore, the use of MLC as an analytical tool allows the direct injection of non-purified samples. The separation was performed with an 80 mM SDS-8.5% propanol eluent at pH 7. Analysis times are below 16 min with a complete resolution. Linearities ( r > 0.9999), as well as intra- and inter-day precision (below 2.7%), were studied in the validation of the method. The limits of detection and quantification ranged from approximately 0.72 to 0.94 and 2.4 to 3.1 ng mL −1, respectively. The detection limit was below the maximum residue limit established by the European Community. Finally, recoveries in spiked milk samples were in the 83–103% range.

Simple and rapid determination of sulfonamides in milk using Ether-type column liquid chromatography

A simplified and rapid determining/identifying method for residual sulfonamides (SAs) in milk by using Ether-type stationary phase, which made in our lab, was presented. The target analytes were extracted by mixing with ethanol–acetic acid (97:3, v/v) followed by centrifugation. The procedure used a Ether-type C8 column, isocratic elution with acetonitrile–water (5:95, v/v), and a photo-diode array detector. The linear range of determination was 50–10,000 μg/L for sulfanilamide and 100–10,000 μg/L for sulfadiazine, sulfamerazine, sulfamethazine. Average recoveries of four SAs (spiked 0.5, 1.0 and 1.5 μg/mL) ranged from 80.1% to 87.6%, with relative standard deviations between 3.4% and 5.8%. The total time and solvent required for the analysis of one sample were <15 min and <1.0 mL of ethanol and 0.6 mL of acetonitrile, respectively. The developed procedure was nearly harmless to the human and environment.

Rapid determination of sulfonamides in milk using micellar electrokinetic chromatography with fluorescence detection

A new method was developed for the determination of sulfonamides in milk by using micellar electrokinetic chromatography coupled with fluorescence detection. Separation of fluorescamine-derivatized sulfonamides was accomplished by using a buffer 13.32 mM disodium hydrogen phosphate, 6.67 mM potassium dihydrogen phosphate and 40 mM sodium dodecyl sulphate at pH 7.5 in addition to positive power supply at 21 kV at 25 °C. Detection was performed using UG-11 excitation filter and 495 nm emission filters. The proposed capillary electrophoresis method allows the separation of five sulfonamides within 7 min with a limit of detection of 1.59–7.68 nmol/L for all the sulfonamides considered for present study. A simple sample preparation method with fairly good recoveries 85–114% is also presented in current paper. Inter-day and intra-day validation of the separation method shows fairly good results. Robustness of the method has also been studied.

Determination of Sulfonamide Residues in Milk by On‐Line Microdialysis and HPLC

A technique for the simultaneous determination of sulfonamides in milk was studied by using a home‐made microdialysis system on‐line to high‐performance liquid chromatography. Six sulfonamides (sulfadiazine, sulfamerazine, sulfamethazine, sulfamonomethoxine, sulfadimethoxine, and sulfamethoxazole) in milk were isolated by a hollow dialysis fiber prior to chromatographic determination. The results shows 2–5 fold enrichments and the detection limits in sub‐µg L−1 levels. As the milk sample was spiked with the six sulfonamides, in the concentration ranges between 0.005 and 10 mg L−1, recoveries ranging from 97.8% to 100.4% were obtained, and the regression coefficients >0.995. The proposed method provides a simple, fast, and eco‐friendly procedure for isolating and determining sulfonamides in milk samples.

MICELLAR CHROMATOGRAPHIC PROCEDURE WITH DIRECT INJECTION FOR THE DETERMINATION OF SULFONAMIDES IN MILK AND HONEY SAMPLES

The capability of liquid chromatography with micellar mobile phases of sodium dodecyl sulfate (SDS), of allowing the direct injection of biological fluids into reversed-phase columns, was applied to the determination of sulfonamides in milk and honey samples. The chromatographic behavior of a group of 15 sulfonamides was studied at pH 3.0 where the drugs showed a greater separation space. Acetonitrile was added to the mobile phase to decrease the retention of the most hydrophobic drugs and increase the efficiencies, which yielded a higher resolution. The samples were diluted with 0.10 M SDS to facilitate the solubilization of the matrix compounds and release the protein-bound drugs. The procedure is simple, rapid, and reliable, has a low cost, and permits screening for 11 sulfonamides (sulfacetamide, sulfadiazine, sulfadimethoxine, sulfaguanidine, sulfamerazine, sulfamonomethoxine, sulfanilamide, sulfapyridine, sulfaquinoxaline, sulfathiazole, and sulfisoxazole) with good accuracy and precision. The recoveries found for milk and honey samples spiked with 1 μg/mL of each sulfonamide, calculated from the calibration straight lines obtained in aqueous solution, were in the ranges 87–108% and 72–119% for milk and honey samples, respectively. Limits of detection were close to 0.1 μg/mL for sulfadiazine, sulfadimethoxine, sulfamethizole, sulfamonomethoxine, sulfanil-amide, sulfathiazole, and sulfisoxazole in milk samples and sulfacetamide, sulfamethizole, sulfanilamide, and sulfapyridine in honey samples.

Determination of Sulfonamides in Milk

Abstract Sulfonamide residues were determined in milk by first treating the milk with acetone and acetic acid and then purifying and concentrating the sulfonamides on an ion exchange column. This method yields a low control reading, an achievement which has been difficult to obtain by other procedures. This control reading, which shows up as false sulfonamides, can result in erroneous recovery and residue data unless a correction procedure is used. The average recovery is 85%, the sensitivity is 0.1 ppm, and the control milk samples read less than 0.1 ppm