Hydrophilic-lipophilic Balance Cartridges Research Articles

Occurrence of antibiotics and antibiotic-resistant bacteria in the Lebanese polluted Litani River.

Antibiotic contamination in polluted rivers is well recognized as an environmental and public health challenge. In this study, the occurrence, distribution, and ecological risk assessment of three commonly used antibiotics (amoxicillin, ciprofloxacin, and azithromycin) were assessed in the Litani River, the most important and highly polluted river in Lebanon. Physicochemical and microbiological water quality parameters including the antibiotic-resistant ones were in parallel determined in the same sites. Water samples from five sites stretching across the river upper basin were analyzed for the antibiotics under study using high-performance liquid chromatography, with both fluorometric and UV detectors post-extraction using a solid-phase method with a hydrophilic-lipophilic balance cartridges. The disc diffusion method and standardized water quality methods were used for antibiotic-resistant bacteria and water quality assessment, respectively. Amoxicillin and ciprofloxacin were found at concentrations of 250 ng/L and 107.2 ng/L, while azithromycin was not detected in any of the sites under study. Varying levels of antibiotic resistance were detected with the isolated Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) while the total coliforms showed resistance to multiple antibiotics. COD, TP, PO43-, TN, NO3-, NH4 + , E. coli, total coliform, P. aeruginosa, and Cd levels surpassed permissible levels. Correlation analysis with water quality parameters (COD, total phosphate, phosphate, total nitrogen, and cadmium) showed a significant positive correlation with ciprofloxacin (r > 0.5, p value < 0.05). Also, the resistant P. aeruginosa showed a significant positive correlation with cadmium (r > 0.5, p value < 0.05) while the resistant E. coli was positively correlated with total nitrogen, nitrate, and lead levels (r > 0.5, p value < 0.05). The ecological risk assessment revealed that all the tested antibiotics pose low risks (ecological risk quotient RQ < 0.1) except ciprofloxacin, which could pose a medium risk (0.1 < RQ < 1). Future research concerning the long-term assessment of antibiotics' residues and the identification of resistance genes in the river is recommended.

Reproducibility in nontarget screening (NTS) of environmental emerging contaminants: Assessing different HLB SPE cartridges and instruments

Non-targeted screening (NTS) methods are integral in environmental research for detecting emerging contaminants. However, their efficacy can be influenced by variations in hydrophilic-lipophilic balance (HLB) solid phase extraction (SPE) cartridges and high-resolution mass spectrometry (HRMS) instruments across different laboratories. In this study, we scrutinized the influence of five HLB SPE cartridges (Nano, Weiqi, CNW, Waters, and J&K) and four LC-HRMS platforms (Agilent, Waters, Thermo, and AB SCIEX) on the identification of emerging environmental contaminants. Our results demonstrate that 87.6 % of the target compounds and over 59.6 % of the non-target features were consistently detected across all tested HLB cartridges, with an overall 71.2 % universally identified across the four LC-HRMS systems. Discrepancies in detection rates were primarily attributable to variations in retention time stability, mass stability of precursors and fragments, system cleanliness affecting fold change and p-values, and fragment response. These findings confirm the necessity of refining parameter criteria for NTS. Moreover, our study confirms the efficacy of the PyHRMS tool in analyzing and processing data from multiple instrumental platforms, reinforcing its utility for multi-platform NTS. Overall, our findings underscore the reliability and robustness of NTS methods in identifying potential water contaminants, while also highlighting factors that may influence these outcomes.

Establishment of HLB-UPLC-MS/MS Method to Determine Hainanmycin Sodium in Chicken Liver

Objective: Controlling coccidiosis disease in poultry is significant for healthy breeding, but antibiotic residues can pose a great threat to food safety, the ecological environment, and human health. A special anticoccidial drug called Hainanmycin has been widely used in Asian countries for many years, while a few studies focus on its detection. In this study, we established a hydrophiliclipophilic balance (HLB) purification and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method to determine the hainanmycin in chicken liver. Methods: It was extracted from the sample with 0.1% formic acid-methanol (10+90, v/v) and then it was purified on a hydrophilic-lipophilic balance (HLB) cartridge. Chromatography separation was performed on an RP-C18 column, and detection of the hainanmycin was done by positive electrospray ionization (ESI＋) under the multiple reaction monitoring (MRM) modes. Results: The quantification ion pair was m/z 907.5 and m/z 846.4. The calibration curve showed excellent linearity in the range of 10 to 1000 μg·L-1, with a correction coefficient of 0.99. When spiked at 5, 100, and 500 μg·kg-1, the recoveries ranged from 80.82% to 88.09%, with the intra-day and interday coefficients of variation from 10.76% to 13.48% and from 10.80% to 12.71%, respectively. The limit of quantification (LOQ) and detection(LOD) were 5.05 μg·mL-1 and 1.55 μg·mL-1, respectively. Conclusion: This method showed high sensitivity and accuracy for determining hainanmycin in chicken liver.

Simultaneous determination of steroid hormones and pharmaceuticals in killer whale (Orcinus orca) faecal samples by liquid chromatography tandem mass spectrometry.

We describe a non-invasive method for profiling selected hormones, pharmaceuticals and personal care products (PPCPs) in killer whales (Orcinus orca) based on analysis of faecal samples by liquid chromatography tandem mass spectrometry (LC-MS/MS). The method targets 21 compounds of interest including glucocorticoids, mineralocorticoids, androgens, estrogens, progestogens, selective serotonin uptake inhibitors and an antibacterial/antifungal agent. This method is suitable for routine simultaneous determination of target compounds in killer whale faecal samples as well as validation of immunoassays for the detection and measurement of steroid hormones in faeces. The optimized method involves extraction of freeze-dried faecal material with reagent alcohol and water followed by isolation of the analytes using solid phase extraction with hydrophilic-lipophilic balance cartridges and liquid-liquid extraction with methyl tertiary-butyl ether. Reconstituted extracts were analysed by LC-MS/MS using an electrospray ionization interface. Method limit of quantification ranged from 0.06 to 45.2ng/g in freeze-dried faecal samples. Except for sertraline, triclosan and estradiol (which was not recovered at the lowest spiked concentration), average intra- and inter-day precisions were within 10%, and average recoveries were between 89.3% and 129.3%, for faecal samples spiked with 5.3, 26.7 or 133ng/g of each analyte. The method was applied successfully to the analysis of hormones and PPCPs in whale faeces during which 17α-hydroxyprogesterone, a common intermediate in steroid biosynthesis that cross-reacts with precursors and sulphated conjugates in immunoassays, was identified and quantified in all samples.

Optimization and Validation of Europium-Sensitized Fluorescence Method for Determination of Tetracycline Antibiotics in Water from Fish Farms

Sensitized europium fluorescence was used for simple, fast and efficient determination of tetracycline residues in water from fish farms. Tetracycline antibiotics: oxytetracycline (OTC), tetracycline (TC) and chlortetracycline (CTC) were extracted from water samples using polymeric hydrophilic–lipophilic balanced cartridges. After evaporation and pre-concentration, tetracyclines form a complex with europium and citric acid as coligand at pH 8.5. The complex formed has a wide absorption spectrum at 388 nm and a narrow emission maximum at 619 nm resulting from the 5D0 - 7F2 transition within the europium ion. The complex is stable with intensive fluorescence and linear in the concentration range of 5-2500 µg/L for tetracycline and oxytetracycline and 5-1000 µg/L for chlortetracycline. The detection limit was 0.68 µg/L for OTC, 1.29 µg/L for TC and 0.65 µg/L for CTC, respectively.The proposed method is very sensitive and particularly applicable to samples where low concentrations of tetracycline antibiotics are expected.

Development of an Analytical Method for Kasugamycin Residue in Herbal Medicine, &lt;i&gt;Achyranthes japonica&lt;/i&gt; Nakai

This study developed a suitable analytical method for kasugamycin residues in Achyranthes japonica using LC/MS/MS equipped with an amide column for polar substances. Extraction and cleanup processes were done at pH 4.5–5. Purification efficiency was assessed and confirmed step by step by selecting silica, hydrophilic-lipophilic balance (HLB), strong cation exchange (SCX), and double (HLB and SCX) cleanup SPE cartridges. The results indicated that silica SPE cartridge exhibited overloading tendency, while HLB SPE cartridge had low cleaning efficiency. Among SPE cartridges used, double cleanup and SCX were found sufficient with respective matrix effects of –15% and +14%, respectively. The LOD and LOQ were 0.008 ng and 0.04 mg/kg, respectively. The correlation coefficient (R2) was higher than 0.99, recovery rate ranges were 86.3–97.2%, and the RSD was below 8.8%. All methods are consistent with the Codex guidelines criteria. This study developed an appropriate LC/MS/MS analytical method for kasugamycin residue analysis in A. japonica with optimized, efficient extraction and purification conditions using a single SCX SPE cartridge, which is simple and time-efficient. In addition, the HLB and SCX SPE cartridges of the double cleanup methods were identified as primary methods that can be applied for the cleanup of other medicinal herbs.

Simultaneous determination of seven bisphenol analogues in surface water by solid-phase extraction and ultra-performance liquid chromatography-tandem mass spectrometry

For the simultaneous determination of seven types of bisphenol analogues (BPs) in surface water, a method combining solid-phase extraction (SPE) with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed. The extraction efficiency was improved by optimizing the parameters that affect it, including the sorbent types of SPE cartridge, pH, enrichment factor, flow rate, rinsing and elution volume. On the basis of the single factor experiments, an attempt to obtain the result of optimizing by response surface methodology was made, and the optimal parameters were as follows: at a flow rate of 8 mL/min, 1000 mL of water sample was run through the hydrophilic-lipophilic balance cartridge, rinsed with 10% methanol, eluted with 9 mL methanol, and concentrated with nitrogen using an automatic SPE system. The analytes were separated on an Acquity UPLC BEH C18 column using gradient elution with a mobile phase of acetonitrile and 0.05% (v/v) ammonia, and then analyzed using UPLC-MS/MS with multiple reaction monitoring in the negative-ion mode, with an 8-minute chromatographic run time. In the range of 1.0–500 μg/L, seven BPs showed good linearity with the correlation coefficient greater than 0.998. The recovery ranged from 82.3 to 96.7%, and the range of matrix effect was 89.2 to 107%. These results indicated excellent recovery and minimal matrix effect. The limits of detection were 0.05–1.5 ng/L, the relative standard deviation ranged from 2.9 to 8.5%. Applying the developed method, seven BPs in Luoma Lake and its inflow rivers were analyzed. Only five BPs were detected in Luoma Lake and four BPs were detected in inflow rivers, and the concentrations of the detected BPs were determined. BPA and BPF were the predominant BPs, and the concentration of BPA was the highest.

Haloquinone Chloroimides as Toxic Disinfection Byproducts Identified in Drinking Water.

Haloquinone chloroimides (HQCs) are suspected to be highly toxic contaminants, and their production during drinking water disinfection is predicted. However, HQC disinfection byproducts (DBPs) have not been reported in drinking water to date because of analytical limitations. In this study, we developed an analytical method to detect five HQCs, including 2,6-dichloroquinone-4-chloroimide (2,6-DCQC), 2,6-dibromoquinone-4-chloroimide (2,6-DBQC), 2-chloroquinone-4-chloroimide (2-CQC), 3-chloroquinone-4-chloroimide (3-CQC), and 2,6-dichloroquinone-3-methyl-chloroimide (2,6-DCMQC). This method combined a derivatization reaction of HQCs with phenol in alkaline solutions to produce halogenated indophenols, a solid-phase extraction pretreatment using hydrophilic-lipophilic balanced (HLB) cartridges, and a multiple reaction monitoring (MRM) method for quantification. The method was demonstrated to be sensitive and accurate with recoveries of 71-85% and limits of detection of 0.1-0.2 ng/L for the five tested HQCs. Using this method, five tested HQCs were identified in drinking water samples from nine water treatment plants and water distribution systems as new DBPs at concentrations of up to 23.1 ng/L. The cytotoxicity of the five tested HQCs in HepG2 cells was higher than or comparable to that of 2,6-dichloro-1,4-benzoquinone (2,6-DCBQ), an emerging DBP that was hundreds to thousands of times more toxic than regulated DBPs. This study presents the first analytical method for HQC DBPs in drinking water and the first set of occurrence and cytotoxicity data of HQC DBPs.

Effective and rugged analysis of glyphosate, glufosinate, and metabolites in Tenebrio molitor larva (mealworms) using liquid chromatography tandem mass spectrometry

Tenebrio molitor larva (mealworms) has recently attracted attention as a protein source for food and feed. The larva is generally fed with wheat bran, which can be possibly contaminated with glyphosate. To establish food safe standards, a rugged and effective analytical method for glyphosate, aminomethylphosphonic acid, glufosinate, and their metabolites including 3-methylphosphinico-propionic acid, and N-acetyl glufosinate, in mealworms was optimized using liquid chromatography tandem mass spectrometry. An anionic polar pesticide column was used due to its high suitability for glyphosate. Acidified water and acetonitrile were used to extract the target compounds without contribution from various fatty and pigment interferences derived from brownish insects. Seven different clean-up procedures ((1) 50 mg C18 (2) 20 mg C18/Z-sep (3) PRiME hydrophilic-lipophilic balance (HLB) cartridge (4) 75 mg Z-sep, (5) 75 mg Z-sep+, (6) EMR-lipid cartridge, and (7) 50 mg ENVI-Carb) were compared. Due to its simplicity and cost-effectiveness, PRiME HLB was selected for clean-up. The recoveries of the target compounds were ranged from 86 to 96% with < 20% relative standard deviations. Therefore, this simple and effective method can be applied for the two pesticides and their metabolites in other edible insects or high-fat matrices.

Automatic analytical approach for the determination of 12 illicit drugs and nicotine metabolites in wastewater using on-line SPE-UHPLC-MS/MS

In this study, we developed a novel on-line solid phase extraction (SPE)-ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS)-based analytical method for simultaneously quantifying 12 illicit drugs and metabolites (methamphetamine, amphetamine, morphine, codeine, 6-monoacetylmorphine, benzoylecgonine, 3,4-methylenedioxymethamphetamine, 3,4-methylenedioxyamphetamine, cocaine, ketamine, norketamine, and methcathinone) and cotinine (COT) in wastewater samples. The analysis was performed by loading 2 mL of the sample onto an Oasis hydrophilic-lipophilic balance cartridge and using a cleanup step (5% methanol) to eliminate interference with a total run time of 13 min. The isotope-labeled internal standard method was used to quantify the target substances and correct for unavoidable losses and matrix effects during the on-line SPE process. Typical analytical characteristics used for method validation were sensitivity, linearity, precision, repeatability, recovery, and matrix effects. The limit of detection (LOD) and limit of quantification (LOQ) of each target were set at 0.20 ng/L and 0.50 ng/L, respectively. The linearity was between 0.5 ng/L and 250 ng/L, except for that of COT. The intra- and inter-day precisions were <10.45% and 25.64%, respectively, and the relative recovery ranged from 83.74% to 162.26%. The method was used to analyze various wastewater samples from 33 cities in China, and the results were compared with the experimental results of identical samples analyzed using off-line SPE. The difference rate was between 19.91% and −20.44%, and the error range could be considered acceptable. These findings showed that on-line SPE is a suitable alternative to off-line SPE for the analysis of illicit drugs in samples.

Method validation, persistence, and safety evaluation of 2,4-D in tea (Camellia sinensis) by LC-MS/MS.

An analytical method was developed by using LC-ESI(-ve)-MS/MS to investigate the residue dynamics of 2,4-D (2,4-dichlorophenoxyacetic acid) in green tea leaves, processed tea, tea liquor, and tea-cropped soil at Singhiajhora Tea Estate and Putinbari Tea Estate at Terai Region, Darjeeling District, West Bengal, India. In this method, an acidified methanol was used for extraction and subsequent clean-up was done by HLB (hydrophilic lipophilic balanced) cartridges. The method was validated as per SANTE guideline (SANTE/11813/2017). The limit of quantification (LOQ) of 2,4-D was 0.05 mgkg-1 and average % recoveries were in the range from 88.05 to 113.28 with relative standard deviation (RSD) 3.46 to 6.43. The dissipation of 2,4-D followed the 1st-order reaction kinetics with a half-life (T1/2) of 1.51-1.61 day at the recommended dose and 2.50-2.72day for doubled recommended dose in tea for both locations. This method can be applied successfully for the determination of 2,4 D residues in/on tea matrix and subsequent studies on safety evaluation showed that the use of 2,4-D in tea is safe.

Development and Validation of a Multi-detection Confirmatory Method for Antibiotics Determination in Piglet Kidneys by UHPLC-TOF-MS According Commission Decision 2002/657/EC

The combination of ultra-high-performance liquid chromatography (UHPLC) with time-of-flight mass spectrometry (ToF-MS) is one of the most powerful analytical tools in terms of selectivity, sensitivity and speed. However, due to the gap on regulation and guidelines concerning the validation criteria for the use of ToF-MS methodology not only for screening but also for confirmatory and quantification purposes, this study presents, for the first time, an approach on how to use the referred methodology for confirmatory and quantification purposes. Thus, an UHPLC-ToF-MS method was developed and validated for the simultaneous determination of 43 antibiotic residues from 7 different families (tetracyclines, sulfonamides, quinolones, penicillins, macrolides, cephalosporins and trimethoprim) in piglet kidneys as a confirmatory method. A simple sample preparation consisting of extraction with a mixture of acetonitrile and ethylenediaminetetraacetic acid (EDTA) followed by solid-phase extraction (SPE) with a hydrophilic-lipophilic balanced (HLB) cartridge and finalized with a defatting step with n-hexane was used. The methodology was validated according the Commission Decision 2002/657/EC, by defining suitable criteria for antibiotic identification, as well as by evaluating required parameters like selectivity, specificity and ruggedness that fulfil the required criteria. The calculated values of decision limit (CCα) and of detection capacity (CCβ) for antibiotics with established maximum residue limits (MRLs) fully complied with required criteria. For antibiotics for which no MRL was set, values ranging from 0.2 to 0.5 μg kg−1 and from 0.5 to 0.8 μg kg−1 were achieved for CCα and for CCβ, respectively. Linearity (all R2 > 0.95), recovery (81.4–110.0%) (lowest values of 4.6% and 7.1% were obtained for repeatability and for reproducibility, respectively), LODs (0.04–13.0 μg kg−1), LOQs (0.09–32.0 μg kg−1) and matrix effects (35.5–118.1 %) were also evaluated. After validation, the method was applied to analyse piglet kidney samples. Antibiotic residues were determined in 10 of the 15 analysed samples. However, all the antibiotics concentrations were below the MRLs.

A solid-phase extraction method that eliminates matrix effects of complex pulp mill effluents for the analysis of lipophilic wood extractives

Abstract The extraction of lipophilic wood extractives from pulp and paper process waters proves to be a challenging task, due to harsh and alternating process and sample conditions. This study has determined the potential use of polymeric sorbents for solid-phase extraction (SPE) and compared to classical silica-based reversed-phase packed columns, with polymeric hydrophilic-lipophilic balanced (HLB) cartridges being the sorbent with the most potential. Recovery functions were obtained with an internal standard mixture representative for the main lipophilic wood extractive groups, which are fatty acids and alcohols, sterols, sterol esters and triglycerides. The impact of pH, sample volume and sample matrix, expressed as TOC and cations, on the retention behavior of lipophilic extractives during SPE of industrial samples were determined with polymeric HLB sorbent. High variations in the composition of pulp mill matrices led to different optimal extraction conditions. Thus, a new SPE protocol was developed, which bypasses matrix interferences and omits the loss of analytes due to sample preparation. The method is applicable to different pulp mill effluents with large discrepancies in pH and sample matrices, resulting in recoveries &gt;90 % with RSD &lt;5 % for all lipophilic wood extractives.

Simultaneous Determination of Malachite Green, Chloramphenicols, Sulfonamides, and Fluoroquinolones Residues in Fish by Liquid Chromatography-Mass Spectrometry.

A fast-analytical method using simplified extraction has been developed for the simultaneous determination of 42 compounds from 4 different classes of veterinary drugs (amphenicols, triphenylmethane, fluoroquinolones, and sulfonamides) in fish by reverse phase liquid chromatography-tandem mass spectrometry. The selection of extraction reagents was optimized using different types of microfiltration membrane, mobile phase, and LC column. Samples were extracted using 0.4% hydrochloric acid in acetonitrile and ethyl acetate and then were cleaned up using solid-phase extraction Cleanert Alumina N columns (500 mg) and Oasis hydrophilic-lipophilic balance (HLB) cartridges. The chromatographic separation was performed on a XR-ODS C8 column using a mobile phase of (A) 0.1% formic acid and 2 mM ammonium acetate and (B) 0.1% formic acid acetonitrile at a flow rate of 0.25 mL·min−1. The results indicated 67.7–112.8% recovery of 42 compounds with an intra- and interday relative standard deviations less than 10%. The limits of quantification for analytes were in the range of 0.3–1.0 μg kg−1 for samples which were satisfactory to support future surveillance monitoring. The method applicability was checked by analyzing 30 fish samples collected from local markets. Two fish samples surpassed the established MRL of 100 μg kg−1 with values of 104 μg kg−1 and 112 μg kg−1.

Combination of coagulant-assisted and SPE purification for the HPLC determination of lycorine and galanthamine in various foods

A simple high performance liquid chromatography (HPLC) method has been developed for the analysis of lycorine and galanthamine, typical alkaloids of narcissus, in food. Samples were extracted with sonication using water containing poly-aluminium chloride (PAC) and sodium hydroxide (NaOH) as a solvent followed by solid phase extraction (SPE) with hydrophilic-lipophilic balanced (HLB) cartridge. Elution of the analytes was achieved with 0.1 v/v% formic acid kept at 95 °C. Purification with PAC, which is normally used as a coagulant, was successfully combined with SPE, demonstrated the perfect strategy for the removal of interfering substances from the foods. Separation of the analytes was achieved on reversed phase C18 column. The analytes were monitored doubly at wavelengths of 240 and 290 nm for the detection. The method demonstrated excellent linearity with coefficients of determination (r(2)) higher than 0.999 over the range of 0.2–20 µg ml−1 for both lycorine and galanthamine. Limits of quantification (LOQs) of the method were in the range of 0.15–0.52 µg ml−1. Method performance was evaluated, demonstrated to have quantitative recoveries of 92.8–98.9% with satisfactory intra-day precision of lower than 3.7% and inter-day precision of lower than 5.0%. The method was also applied to a wide variety of foods with complex matrices, indicated the potential of practical use in plant poisoning caused by narcissus contaminated foods.

Simultaneous determination of 14 sexual hormones in health care products by ultra performance liquid chromatography-atmospheric pressure chemical ionization-triple quadrupole mass spectrometry

A comprehensive analytical method was developed for the simultaneous determination of 14 sexual hormones in health care products by ultra performance liquid chromatography-atmospheric pressure chemical ionization-triple quadrupole mass spectrometry (UPLC-APCI-MS/MS). The samples were extracted twice with acetonitrile and the extracts were purified using hydrophilic-lipophilic balance (HLB) cartridges. Chromatographic separation was achieved on a Hypersil Gold C18 column (100 mm×2.1 mm, 1.9 μm) by gradient elution with acetonitrile and 10 mmol/L ammonium acetate aqueous solution as the mobile phases. Compounds were detected by APCI-MS/MS with external standard calibration curve method. All the 14 sexual hormones showed a good linear trend in their respective concentration ranges and the correlation coefficients (r) were no less than 0.996. The limits of detection (LODs) ranged from 0.0990 μg/kg to 2.09 μg/kg. The limits of quantification (LOQs) were in the range of 0.495-5.23 μg/kg. The average recoveries of the 14 sexual hormones in the health care product samples ranged from 65.8% to 118.8% at the three spiked levels. The precisions (n=6) ranged from 0.6% to 8.7% (n=6). The method is simple, sensitive, accurate and precise, and is suitable for the determination of the illegal added sexual hormones in the health care products.

Determination of naproxen, diclofenac and ibuprofen in Umgeni estuary and seawater: A case of northern Durban in KwaZulu–Natal Province of South Africa

In recent years, the occurrence of pharmaceuticals including non-steroidal anti-inflammatory drugs in Umgeni River water system in South Africa has been a concern to the scientific community. In this study; naproxen, diclofenac and ibuprofen were isolated from various water samples (river, estuarine and sea water) using the solid-phase extraction technique based on Oasis hydrophilic–lipophilic balance cartridges. The extracted compounds were identified and quantified using high performance liquid chromatography-photo diode array detector. Validation of the analytical method was performed by spiking seawater with a mixture of all the three pharmaceuticals at 0.025 μg/L. Percentage recoveries for naproxen, diclofenac and ibuprofen were 82.3, 65.5 and 79.5%, respectively. The analytical method quantitation limits for naproxen, diclofenac and ibuprofen were 0.025, 0.036 and 0.035 μg/L, respectively. Diclofenac was not detected in any of the analysed river, estuarine and seawater samples. Naproxen was quantified in all water samples and reached a maximum concentration of 0.36 μg/L in river water. In seawater, naproxen and ibuprofen were detected up to 0.16 and 0.17 μg/L respectively. The occurrence of these pharmaceuticals in water resources is a cause of concern due to potential impacts on the wellbeing of aquatic organisms and humans.

Using size-exclusion for improved extraction of trace organic compounds from landfill leachate.

Pharmaceuticals, plasticisers and other trace organic contaminants have been reported in landfill leachates, with most methods using hydrophilic-lipophilic balance cartridges for solid phase extraction. However, leachate has a high organic load and can quickly coat the cartridge media and prevent target compounds from being extracted. There are several solid phase extraction cartridges that offer size exclusion in addition to adsorption, where only small molecules are allowed to diffuse into the resin pores where adsorption in happening. Three cartridges with size exclusion properties were evaluated in comparison with hydrophilic-lipophilic balance cartridges for extraction of several trace organic contaminants spiked into landfill leachate. All three cartridges with size exclusion properties showed some improvement in extraction compared with hydrophilic-lipophilic balance, although the differences were not statistically significant at 95% confidence interval. Nevertheless, media with size-exclusion properties offers a viable alternative to hydrophilic-lipophilic balance for extracting small molecules of trace organics from complex environmental matrices.

Development of a PRiME cartridge purification method for rapid determination of malachite green and leucomalachite green in Chinese softshell turtle.

A high-throughput PRiME (process, robustness, improvements, matrix effects, ease of use) sample purification procedure was developed to simplify the multiple steps of traditional SPE in extracting the malachite green and leucomalachite green in Chinese softshell turtle (Pelodiscus sinensis). The sample loading volume, extracting solvent type, and pH value of the employed PRiME hydrophilic-lipophilic balance cartridge for sample purification were optimized to be 3 mL, acetonitrile, and pH 5, respectively. In comparison with traditional SPE, the PRiME process is cost-effective, solvent-saving, and simple to operate, which only consists of a passing through step without traditional sorbent conditioning and impurity washing. Afterward, eluate was analyzed by ultra-performance liquid chromatography-tandem mass spectrometry, and the proposed method was validated for linearity (R2 > 0.9992), intraday precision (2.44-3.22%), interday precision (3.28-6.58%), sensitivity (LOD ≤ 0.18 μg/kg and, LOQ ≤ 0.60 μg/kg), and recovery (88.7-94.1%, RSD < 6.79%). The results indicated that the PRiME technique can simplify the sample preparation procedure by avoiding the tedious steps, such as conditioning, washing, etc. It would be of significant interest for environmental and food safety applications in the market of Chinese softshell turtle and related products.

[Determination of nine pesticide residues in honey using high performance liquid chromatography-tandem mass spectrometry].

A method is proposed for the simultaneous determination of nine benzimidazole and neonicotinoid pesticides present in honey by employing automatic solid-phase extraction with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). A honey sample was dissolved in a phosphate buffer (pH=7.8) followed by ultrasonic extraction. The extracts were then purified through solid-phase extraction (SPE) with hydrophilic-lipophilic balance (HLB) cartridges. Finally, nitrogen was blown on the obtained mixture, and the mixture was subsequently filtered for conducting HPLC-MS/MS analysis. Nine compounds were detected under the multiple reaction monitoring (MRM) mode, and the corresponding quantification was performed by employing the method of internal standards. The nine detected pesticides demonstrated good linearity in the range of 0.002-0.05 mg/L, with the correlation coefficient values (r2) being higher than 0.99. The limits of detection (LODs) (S/N=3) and limits of quantification (LOQs) (S/N=10) were found to be in the ranges of 0.1-1.0 μg/kg and 0.3-2.0 μg/kg, respectively. Furthermore, the results indicated that the recoveries of the nine detected pesticides range from 78.2%-101.2% at three spiked levels of 5.0, 10.0, and 20.0 μg/kg with a relative standard deviation (RSD) range of 1.3%-14.3% (n=6). Hence, the proposed method is rapid and can be employed for accurate determination of pesticide residues in large quantities of honey samples.