Method For Simultaneous Determination Research Articles

Development of LC–MS/MS Method for the Simultaneous Detection of Emerging Contaminants in Aquatic Matrices

Emerging contaminants (ECs) are substances that have no defined environmental quality standards or regulations, and have the potential to pose major adverse impacts on the environment and human health. The detection of contaminants in the natural environment is the key step for establishing precise environmental risk assessment approach for ECs. However, ECs come from different origins with various physicochemical properties, making their detection a complicated process. Moreover, their presence in the aquatic environment at trace concentration range (ng/L-µg/L), requires an accurate detection at low concentration levels. This study aims to develop an efficient analytical method for simultaneous determination of 5 different ECs in aqueous solution based on solid phase extraction technique (SPE) followed by liquid chromatography-mass spectrometry (LC–MS/MS). High recovery rates (72% to 114%) were achieved for all targeted compounds. Ciprofloxacin (CIP), diuron (DIU), terbutryn (TER) and diclofenac (DIC) had a limit of detection (LOD) of 5 µg/L and a limit of quantification (LOQ) of 10 ng/L, while LOD and LOQ for EE2 were 25 µg/L and 50 ng/L, respectively. These results confirm that the optimized method can be applied for extraction and analysis of ECs from different classes in the aquatic environment.

APPLICATION OF VALIDATED RP-HPLC METHOD FOR SIMULTANEOUS DETERMINATION OF METAXALONE AND DICLOFENAC POTASSIUM IN PLASMA

Objective: The present investigation demonstrates a simple, sensitive and accurate high-pressure liquid chromatographic (HPLC) method for simultaneous determination of metaxalone (MTX) and Diclofenac potassium (DIC) in plasma by using Valsartan (VSN) as internal standard. Methods: The chromatographic separation was achieved within 10 min by using methanol: potassium dihydrogen phosphate buffer pH 4.5 adjusted with orthophosphoric acid (60:40) as mobile phase on Altima Grace Smart C-18 column (5μ; 250×4.6 mm) at flow rate of 1.0 ml/min with injection volume 25µl. The drug was extracted from plasma by liquid-liquid extraction using methanol as a solvent. The retention times of drugs (MTX and DIC) and internal standard were found to be 5.83, 9.65 and 11.79 min, respectively. This method was validated as per United States Food and Drug Administration (US-FDA) guidelines. Results: The results of the validation parameters were found to be within the acceptance limits. The method was linear in the concentration range from 25-1000 ng/ml (r2= 0.9998) and the extraction recovery was found to be 77.06% for MTX and 78.37% for DIC. The lower limit of quantification was found to be 25ng/ml and the stability of recovered samples at different conditions were found to be more than 95% for both the drugs. Conclusion: The developed method possesses good selectivity specificity, there was no interference found in the plasma blanks at retention times of MTX and DIC. We found good correlation between the peak area and concentration of the drug under prescribed conditions. Furthermore, the method can also be used to estimate the pharmacokinetic parameters of MTX and DIC simultaneously.

Innovative eco-friendly stability-indicating HPLC-PDA method for simultaneous determination of the emerging antiviral drugs against COVID-19 infection molnupiravir and favipiravir; degradation kinetic studies along with LC-MS based structure elucidation

The adoption of the principles of green chemistry in analytical procedures lowers the negative influence on both people and the environment, which presently has become the key goal. Additionally, the need for advanced analytical techniques for the simultaneous determination of antiviral combinations is highly recommended, one of those novel combinations that recently proved effective emerging antiviral drugs in the treatment of SARS-COV-2 is molnupiravir (MOL) and favipiravir (FAV). Therefore, the establishment of simple and precise stability-indicating HPLC-PDA method for their simultaneous determination is crucial for the probable co-formulation. The stability of MOL was studied along with FAV after forced degradation of both under different stress conditions Separation of MOL, FAV, and their corresponding degradation products was achieved by simple isocratic HPLC-PDA method using a mobile phase comprised of 25.0 mM phosphate buffer (pH 3.0 ± 0.05) − methanol (70:30, v/v) at flow rate 1.0 mL/min. A Zorbax C18 (250 × 4.6 mm, 5 μm; Agilent Technologies, USA) column was used for the separation of the components and the column oven was maintained at 30 °C, the selected wavelength for detection of both analytes and their degradation products was 230.0 nm. The method was linear over the range of 1.0 – 200.0 µg/mL for both MOL and FAV. MOL was found to be susceptible to all forced degradation conditions, namely, acid, alkali, oxidative, thermal, and photodegradation while FAV was susceptible only to acid, alkali, and oxidative degradation. The probable degradation mechanisms were assumed through the evaluation of the MS1 fragmentation pattern of the degradation products, also studying the kinetic behavior of the degradation reactions. Furthermore, the greenness profile for the proposed method was evaluated utilizing the new Complementary Green Analytical Procedure Index method (ComplexGAPI), and analytical greenness (AGREE) metrics with a score of the later one equals to 0.61 that indicated the greenness evaluation of the method. In addition, the new blue applicability grade index (BAGI) which is complementary to the green metrics showed a score of 85.0 that presents a good applicability potential of the method. The proposed method is the first sustainable, stability-indicating method developed for the simultaneous determination of this potential combination that would help in manufacturing both drugs in a fixed-dose drug combination.

A novel, intelligent and computer-assisted electrochemical sensor for extraction and simultaneous determination of patulin and citrinin in apple and pear fruit samples

In this work, a novel electrochemical sensor was fabricated for simultaneous determination of patulin (PT) and citrinin (CT) in apple and pear fruit samples. A glassy carbon electrode (GCE) was modified with graphene-multiwalled carbon nanotubes-ionic liquid (Gr-MWCNTs-IL) which was used as a platform to electrochemical synthesis of molecularly imprinted polymers (MIPs) by using PT and CT as templates, maleic acid as a functional monomer, and ethylene glycol dimethacrylate as a cross linker with the aim of preconcentration and simultaneous determination of the PT and CT. Experimental variables affecting fabrication of the structure of the sensor and hydrodynamic differential pulse voltammetric (HDPV) response of the sensor were optimized by a small central composite design and desirability function. After optimization, the HDPV responses of the sensor were calibrated by multivariate calibration methods in the ranges of 0.5–13 fM and 1.5–18 fM for PT and CT, respectively, with the help of PLS-1, RBF-PLS, rPLS, LS-SVM, and RBF-ANN with the aim of selecting the best algorithm to assist the sensor. Our results confirmed the best performance was observed from RBF-ANN which was used for the analysis of apple and pear fruit samples. Limit of detections of the sensor assisted by RBF-ANN for determination of PT and CT were 0.08 and 0.61 fM, respectively. Several commercial brands were analyzed by the use of sensor assisted by RBF-ANN and HPLC-UV, and the results confirmed performance of the sensor was admirable and comparable with the reference method with lower cost, faster response, and easier procedure which made it to be a reliable alternative method for simultaneous determination of PT and CT in real matrices.

Study on pharmacokinetics and tissue distribution of deoxypodophyllotoxin and its metabolites in tumour-bearing mice

To study the pharmacokinetics of deoxypodophyllotoxin and its metabolites in non-small cell lung cancer (NSCLC) bearing mice. Using the established LC-MS/MS method for simultaneous determination of deoxypodophyllotoxin and its three main metabolites (M1, M2 and M7) in biological samples, the concentrations of deoxypodophyllotoxin and its metabolites in plasma, tumour and major tissues of tumour-bearing mice were investigated after 6.25 and 25 mg/kg intravenous administration of deoxypodophyllotoxin. The exposure results of drug concentration showed that after intravenous injection of 6.25 and 25 mg/kg of DPT into tumour-bearing mice, the AUC ratio of DPT in tumour tissue to DPT in plasma was 4.23 and 3.80, respectively. While, the AUC ratio of metabolite M2 in tumour tissue to M2 in plasma was 0.82 and 0.76, respectively. Deoxypodophyllotoxin had higher affinity with tumour tissues than plasma, while its metabolite M2 had less affinity with tumour tissues than deoxypodophyllotoxin, but the exposure level of M2 in plasma was higher than that of deoxypodophyllotoxin. Deoxypodophyllotoxin was widely distributed in tumour-bearing mice. After intravenous injection of 25 mg/kg deoxypodophyllotoxin, the concentration of deoxypodophyllotoxin in other tissues except liver and muscle was relatively high, especially in lung, fat and reproductive organs.

Concepts for a New Rapid and Simple HPLC Method for Simultaneous Determination of Rosuvastatin and Perindopril in Dosage Forms

ABSTRACTSimultaneous determination of a tandem of drugs like perindopril and rosuvastatin with differences in water and organic solvent solubilities, hydrophobicity, polarities, and UV‐absorbing possibilities between them necessitates careful selection of chromatographic conditions. The four specified and different bonded reversed‐phase columns were tested with running mobile phases containing various composition contents concepts; the concept of using diluted trifluoroacetic acid in mobile phase composition with acetonitrile enabled simultaneous acidification and weak ion‐pairing with protonized molecules of analytes, yielding appropriate, short, reasonable run times and resolutions of analytes, satisfying UV‐transparency, and good peak symmetries. These facts especially stand for the peak of perindopril, as a member of the group of proline‐containing moiety in its structure, often and easily prone to peak‐tailing, skewing, or splitting on the high‐performance liquid chromatography chromatograms, which is usually solved by using alkyl‐sulfonate base and ion pairs on higher concentrations of buffering salts with low pH values and with column temperatures increasing by 50°C–60°C. Linearity range was 0.002/004–0.5 mg/mL. The score for method AGREE was 0.73–0.77. The method development approaches, with all columns employing our concepts in mobile phases and experimental conditions, can cover the complete needs and demands of quality control departments and laboratories as simple high‐throughput analysis methods.

Development of Sensitive and Simultaneous Determination Method for Thirty-Seven D/L-Amino Acids by Automatic Pre-column <i>o</i>-Phthalaldehyde- Derivatization with Chiral Thiol Using High Performance Liquid Chromatography

Development of Sensitive and Simultaneous Determination Method for Thirty-Seven D/L-Amino Acids by Automatic Pre-column <i>o</i>-Phthalaldehyde- Derivatization with Chiral Thiol Using High Performance Liquid Chromatography

Development of a Rapid Method for Simultaneous Determination of Pesticides in Plant Oil Using GC-MS/MS

Development of a Rapid Method for Simultaneous Determination of Pesticides in Plant Oil Using GC-MS/MS

Stability-Indicating TLC-Densitometric and HPLC Methods for Simultaneous Determination of Teneligliptin and Pioglitazone in Pharmaceutical Dosage Forms with Eco-Friendly Assessment.

The combination of teneligliptin hydrobromide hydrate and pioglitazone hydrochloride in pharmaceutical formulations has improved type 2 diabetes management. Two chromatographic methods TLC-densitometry and RP-HPLC were developed for simultaneous quantification of teneligliptin hydrobromide hydrate and pioglitazone hydrochloride in pharmaceutical formulations, ensuring accuracy and stability assessment. The TLC method uses a mobile phase of methanol, toluene, ethyl acetate and triethylamine (1:7:2:0.1, v/v/v/v) on TLC silica gel plates, scanned at 268nm. The RP-HPLC method employs isocratic elution with acetonitrile and sodium acetate buffer (adjust pH3.6 with glacial acetic acid, 60:40v/v) on a shimpack C18 column (250 × 4.6mm i.d., 5μm), detected at 235nm. Both methods offer high accuracy and reliability, making them valuable for pharmaceutical quality control. Additionally, an environmental impact assessment was conducted using eco-scale, Analytical Greenness Metric Approach, Green Analytical Procedure Index, and national environmental method index to evaluate solvent consumption, waste generation and energy usage. Statistical comparisons (t-tests and F-tests) validate the outcomes of both methods, ensuring their effectiveness in drug formulation analysis. These methods can enhance pharmaceutical quality control while fulfilling environmental responsibilities.

Development of a dynamic multiple reaction monitoring LC-APCI-MS/MS method for quantification of ten nitrosamines in ranitidine API with simple extraction approach

Nitrosamines (NAs) are classified as probable or possible human carcinogens by the International Agency for Research on Cancer (IARC) and the presence of these impurities has resulted in numerous drug recalls from the market. In April 2020, ranitidine which is prescribed to reduce the amount of acid secreted by the stomach has been recalled owing to contamination with NAs. In this work, a simple and sensitive method for simultaneous determination of 10 NAs were developed, utilizing atmospheric pressure chemical ionisation source coupled liquid chromatography tandem mass spectrometer (LC-APCI-MS/MS). By performing dynamic multiple reaction monitoring (dMRM) mode, 10 NAs were separated on a Poroshell HPH C18 (4.6 x 150 mm, 2.7 µm) column with gradient elution implementing mobile phase A consisting of 0.2 % formic acid in water and mobile phase B consisting of methanol in 17 min. The proposed analytical method was successfully implemented in active pharmaceutic ingredient (API) of ranitidine with a water-based extraction procedure. Good linearity with a correlation coefficient (R2) ≥ 0.994 was accomplished over the concentration in range of 0.5–50 ng/mL. The limits of detection (LODs) ranged in 0.06–0.17 ng/mL and limits of quantitation (LOQs) ranged in 0.21-0.58 ng/mL of the method met thresholds of US Food and Drug Administration (US-FDA) and European Medicines Agency (EMA) for testing of NAs. The accuracy of the developed method ranged from 83.1% to 111.9 % and the percent relative standard deviation (%RSD) was ≤ 8.9.

GC-MS method for simultaneous determination and pharmacokinetic investigation of five volatile components in rat plasma after oral administration of the essential oil extract of Pogostemoncablin

Pogostemon cablin (PC) is a traditional Chinese medicine (TCM) and food as well as an important essential oil plant in China. PC essential oil exerts pharmacological effects such as anti-inflammatory, anti-oxidant, anti-platelet, anti-thrombotic, and anti-depressant. This study established a reliable and sensitive gas chromatography-mass spectrometry (GC-MS) method for the simultaneous determination of the pharmacokinetics of patchouli alcohol, β-elemene, β-caryophyllene, caryophyllene oxide, and farnesol in the plasma of rats after oral administration of PC essential oil extract. Using ethyl acetate to prepare the plasma samples, and p-menthone was used as the internal standard (IS). An HP5-MS column (0.25 μm × 0.25 mm × 30 m) was used for chromatographic separation, and detection was performed in selected ion monitoring (SIM) mode. The accuracies of intra-day and inter-day for all analytes displayed a range of −6.7 %–9.2 %, with precision below 12.5 %. Extraction recoveries for analytes ranged from 74.0 to 106.4 % and matrix effects ranged from 92.4 to 106.9 %. Stability results have demonstrated that the relative standard deviations (RSD) of analytes were below 12.1 %. Therefore, the developed GC-MS method successfully evaluated the pharmacokinetics of five volatile components in PC essential oil extract administered orally to rats.

A robust ultra-performance liquid chromatography-tandem mass spectrometry method for simultaneous determination of 10 components in glutathione cycle.

Glutathione (GSH) is an important antioxidant that is generated and degraded via the GSH cycle. Quantification of the main components in the GSH cycle is necessary to evaluate the process of GSH. In this study, a robust ultra-performance liquid chromatography-tandem mass spectrometry method for the simultaneous quantification of 10 components (GSH; γ-glutamylcysteine; cysteinyl-glycine; n-acetylcysteine; homocysteine; cysteine; cystine; methionine; glutamate; pyroglutamic acid) in GSH cycle was developed. The approach was optimized in terms of derivative, chromatographic, and spectrometric conditions as well as sample preparation. The unstable thiol groups of GSH, γ-glutamylcysteine, cysteinyl-glycine, n-acetylcysteine, cysteine, and homocysteine were derivatized by n-ethylmaleimide. The derivatized and underivatized analytes were separated on an amino column with gradient elution. The method was further validated in terms of selectivity (no interference), linearity (R2>0.99), precision (% relative standard deviation [RSD%] range from 0.57 to 10.33), accuracy (% relative error [RE%] range from -3.42 to 10.92), stability (RSD% < 5.68, RE% range from -2.54 to 4.40), recovery (RSD% range from 1.87 to 7.87) and matrix effect (RSD% < 5.42). The validated method was applied to compare the components in the GSH cycle between normal and oxidative stress cells, which would be helpful in clarifying the effect of oxidative stress on the GSH cycle.

Validated LC/MS method for simultaneous determination of elbasvir and grazoprevir in human plasma

A sensitive and accurate LC/MS method for the determination of elbasvir (ELB) and grazoprevir (GZP) in human plasma was established using daclatasvir (DCT) as an internal standard. The analytes were separated on a Waters Spherisorb phenyl column (150 mm x 4.6 mm ID, 5 µm particle size) maintained at 40°C ± 2°C. Gradient elution, at a flow rate of 0.8 mL min-1, was used. The mobile phase consists of 90% of acetonitrile mixed to 10% of a 5 mM ammonium formate buffer (+ 0.1% v/v of trimethylamine, pH was adjusted to 3.2 by formic acid) as phase A and 10% of acetonitrile mixed to 90% of the same buffer as phase B. Liquid-liquid extraction with ethyl acetate solvent was used to recuperate compounds from plasma. The method was validated over a concentration range of 2 and 100 ng/mL for GZP and between 1 and 50 ng/mL for ELB. The intra- and inter-day precision and accuracy of the quality control samples at low, medium, and high concentration levels exhibited relative standard deviations (RSD) < 15%, and the accuracy values ranged from 94.2% to 107.8%. The robustness of the method was established using a two-level full factorial design.

Assessment and Comparison of Greenness of UV-Spectroscopy Methods for Simultaneous Determination of Anti-Hypertensive Combination

Assessment and Comparison of Greenness of UV-Spectroscopy Methods for Simultaneous Determination of Anti-Hypertensive Combination

Investigation of the formation of furfural compounds in apple products treated with pasteurization and high pressure processing

The thermal treatment carried out in the processing of apple products is very likely to induce Maillard reaction to produce furfurals, which have raised toxicological concerns. This study aimed to elucidate the formation of furfural compounds in apple products treated with pasteurization and high pressure processing (HPP). The method for simultaneous determination of five furfural compounds including 5-hydroxymethyl-2-furfural (5-HMF), furfural (F), 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF), 2-acetylfuran (FMC), and 5-Methyl-2-furfural (MF) using high performance liquid chromatography equipped with diode array detector (HPLC-DAD) was successfully developed and validated. All five furfurals exhibited an increasing trend after the pasteurization treatment of apple clear juice, cloudy juice, and puree. 5-HMF, F, FMC, and MF were increased significantly during the precooking of apple puree. Whereas there was no significant change in the furfurals formation after apple products treated with high pressure processing (HPP) with 300 MPa and 15 min. Based on the variation of the fructose, glucose and sucrose detected in apple products after thermal treatment, it revealed that the saccharides and thermal treatment have great effect on the furfural compounds formation. The commercial fruit juice samples with different treatments and fruit puree samples treated with pasteurization were also analyzed. Five furfurals were detected more frequently in the fruit juice samples treated with pasteurization or ultra-high temperature instantaneous sterilization (UHT) than those treated with HPP. 5-HMF and FMC were detected in all fruit puree samples treated with pasteurization, followed by F, MF, and HDMF with the detection rate of 79.31 %, 72.41 %, and 51.72 %. The results could provide a reference for risk assessment of furfural compounds and dietary guidance of fruit products for human, especially for infants and young children. Moreover, moderate HPP treatment with 300 MPa and 15 min would be a worthwhile alternative processing technology in the fruit juice and puree production to reduce the formation of furfural compounds.

Development of a RP-HPLC method for simultaneous determination of atenolol, metoprolol tartrate and phenol red for in-situ rat intestinal perfusion studies

Single-pass intestinal perfusion (SPIP) method is a widely used experimental model to determine the intestinal permeability of drugs. These studies are performed in the presence of a reference standard (metoprolol, MT) and a zero permeability marker (phenol red, PR). Therefore, it is important to develop a validated method for simultaneous determination of the investigated compound along with MT and PR. The aim of this study was to develop a reversed phase high-performance liquid chromatography (RP-HPLC) method with UV-detection for the simultaneous determination of atenolol (ATN), MT, and PR in the perfusion medium used in SPIP experiments. Separation of compounds were performed using an InertSustain C18 (250 × 4.6 mm, 5 µm) HPLC column at 35 °C. The mobile phase was a mixture of acetonitrile and phosphate buffer (pH 7.0, 12.5 mM) in gradient elution, and was delivered at a flow rate of 1 mL/min. The acetonitrile ratio of the mobile phase increased linearly from 10 to 35 % over 15 min. The injection volume was 20 µL, and ATN, MT and PR were detected at 224 nm. The retention times under optimum HPLC conditions were 5.028 min, 12.401 min, and 13.507 min for ATN, MT and PR, respectively. The developed RP-HPLC method was validated for selectivity, specificity, calibration curve and range, accuracy and precision, carry-over effect, stability, reinjection reproducibility, recovery and robustness. The method was linear for ATN (0.76–50 μg/mL), MT (1.14–50 μg/mL), and PR (0.47–20 μg/mL) with determination coefficients of 0.9999, 0.9994 and 0.9998, respectively. The results obtained for all validation parameters of the developed RP-HPLC method met the required limits of the ICH M10 Guideline.

The single adsorbent nano-TiO2 modified QuEChERS for simultaneous determination of 18 pyrrolizidine alkaloids in ginseng samples via LC-MS/MS

Pyrrolizidine alkaloids (PAs) are a group of naturally occurring toxins, which have been widely found in herbs. However, the complexity of the herbs made the accurate and simple determination of PAs challenging. Herein, the present work described the development of a simple and effective QuEChERS method for simultaneous determination of 18 PAs in various ginseng samples. The extraction and purification processes were systematically optimized and validated coupled to LC-MS/MS analysis. After intensive screening, a single adsorbent nano-TiO2 was employed as a cleanup adsorbent during the dispersive solid phase extraction process to remove the matrix interferences and retain the target PAs in the sample solution, achieving the simultaneous determination of 18 PAs. The validation results displayed that the PAs had good linearity, sensitivity and satisfactory accuracy by the developed method. The method LODs and LOQs of PAs ranged from 0.05-1.49 μg/kg and 0.17–4.95 µg/kg, respectively. The average recoveries were 70.1 %-111 % with RSD less than 13 % under different spiked concentrations. Compared to the conventional QuEChERS method, this method gave rise to better purification effect and recoveries under the condition of only using one adsorbent nano-TiO2, which obvious improved its simplicity and versatility. Furthermore, this method was used to analyze the real ginseng samples and PAs were detected with concentrations ranging from 1.02 to 139 μg/kg, which further verified the feasibility of the developed method in the PAs analysis from the traditional herbal medicines.

Development and Validation of a RP-HPLC Method for the Simultaneous Determination of Silver Sulfadiazine and Sodium Hyaluronate in the Presence of Methyl and Propyl Paraben in a Pharmaceutical Cream for Burns.

A direct and precise isocratic RP-HPLC method for simultaneous determination of silver sulfadiazine (SSD) and sodium hyaluronate (SH) in the presence of methyl (MP) and propyl parabens (PP) was developed and validated. Agilent chromatograph with X-Select C18 column (250 × 4.6mm2, 5μm) was used. Chromatographic separation was achieved using a mobile phase consisting of acetonitrile and 0.05M phosphate buffer (pH5.0 to which added triethyl amine 0.5ml/L), at a ratio 35: 65v/v. Elution was used at flow rate of 1.0mL/min at ambient temperature with UV detection at 205nm. The retention times for SH, SSD, MP and PP were 1.49, 3.3, 6.7 and 19.5min, respectively. The presented chromatographic method was fully validated in accordance with ICH requirements, it was valid over linearity ranges of (0.80-100.00μg/mL) and (3.20-100.00μg/mL) for SSD and SH, respectively. Acceptable precision and accuracy were obtained for concentrations over the standard curve ranges and the sensitivity of the method, as the limits of detection and quantification for each active ingredient was also determined. The validated method was successfully applied for the quantification of SSD and SH in pharmaceutical cream formulation and the mean recovery %±SD were 100.93 ± 0.985 and 100.05 ± 0.668 for SSD and SH; respectively, indicating satisfactory accuracy of the method.

Cyclodextrin-based ternary supramolecular deep eutectic solvents for efficient extraction and analysis of trace quinolones and sulfonamides in wastewater by adjusting pH

BackgroundAntibiotics residues can accelerate the growth of drug-resistant bacteria and harm the ecological environment. Under the effect of enrichment and biomagnification, the emergence of drug-resistant pathogenic bacteria may eventually lead to humans being ineffective to drugs in the face of bacterial or fungal disease infections in the future. It is urgent to develop an efficient separation medium and analytical method for simultaneous extraction and determination of antibiotics in the water environment. ResultsThis work doped 2,6-Di-O-methyl-β-cyclodextrin, randomly methyl-β-cyclodextrin, 2-hydroxypropyl-β-cyclodextrin with thymol:fatty acid respectively to construct non-covalent interaction-dominated pH-responsive ternary supramolecular deep eutectic solvents (SUPRADESs), which can undergo a hydrophilic/hydrophobic transition with aqueous phase to achieve an efficient microextraction. Semi-empirical method illustrated that SUPRADESs have a wide range of hydrogen bond receptor sites. We developed a SUPRADES-based analytical method combined with liquid chromatography-triple quadrupole mass spectrometry for the extraction and determination of trace quinolones and sulfonamides in wastewater. The overall limits of detection of the method were 0.0021–0.0334 ng mL−1 and the limits of quantification were 0.0073–0.1114 ng mL−1. The linearity maintained good in the spiked level of 0.01–100 ng mL−1 (R2 > 0.99). The overall enrichment factors of the method were 157–201 with lower standard deviations (≤8.7). SignificanceThe method gave an extraction recovery of 70.1–115.3 % for 28 antibiotics in livestock farming wastewater samples from Zhejiang, China, at trace levels (minimum 0.5 ng mL−1). The results demonstrated that inducing the phase transition between SUPRADES and aqueous phase by adjusting pH for extraction is a novel and efficient pretreatment strategy. To our knowledge, this is the first application of cyclodextrin-based ternary SUPRADESs with pH-responsive reversible hydrophobicity-hydrophilicity transition behavior in wastewater analysis.

A validated high‐performance liquid chromatography‐tandem mass spectrometry method for simultaneous determination of irinotecan and two major metabolites in rat plasma: Application for the pharmacokinetics study

AbstractA high‐performance liquid chromatography‐tandem mass spectrometry method has been developed for the determination of irinotecan, 7‐ethyl‐10‐hydroxycamptothecin (SN38), and SN38 glucuronide (SN38G) in rat plasma in the present study. The analytes were separated on a C18 column and a triple‐quadrupole mass spectrometry equipped with an electrospray ionization source was applied for detection. Irinotecan, SN38 and SN38G could be well retained in the C18 column after optimization of mobile phase. A simple protein precipitation was used to pretreat the plasma. The extraction recovery was above 90% and the matrix effect could be negligible. The method was linear over the concentration ranges of 3.46–3458.8 ng/mL for irinotecan, 2.53–2530.0 ng/mL for SN38 and 2.5–2500.0 ng/mL for SN38G. The precision and accuracy was within the acceptable limits. The simple and convenient method was validated and successfully applied to support the pharmacokinetic study and elucidate the mechanism of irinotecan‐induced diarrhea after irinotecan was intravenously injected to the Sprague‐Dawley rats.