Solid-phase Extraction Purification Research Articles

Determination of calcium β‑hydroxy-β-methylbutyrate content in special medical formula food and sports nutrition food by solid-phase extraction and high performance liquid chromatography

Calcium β‑hydroxy-β-methylbutyrate (CaHMB) can promote muscle growth, prevent muscle atrophy, and enhance immunity, therefore, it is widely used as a nutritional supplement in special medical formula food and sports nutrition food. Many methods for the detection of CaHMB have been reported, but the pretreatment method for these reported literatures directly involves extraction using hydrochloric acid solution, without any purification steps. A method for accurately determining CaHMB in special medical formula food and sports nutrition food was established for the first time using solid-phase extraction (SPE) purification and high-performance liquid chromatography method (HPLC). The samples were extracted and precipitated protein using methanol-water solution, purified using SPE method and analyzed by HPLC on diode array detector (DAD) mode under external standard method. The method obtained excellent calibration linearity (r2>0.9993) and a satisfactory analysis of the targeted compound, which were evaluated with calibration standards over the range of 0.020–2.00 mg/mL. The limit of quantifications (LOQs), which defined as the lowest spiking level, were set at 0.4 g/100 g (special medical formula food) and 1.0 g/100 g (sports nutrition food). The average recoveries were within 92.9–104% for the analytes, and the relative standard deviations (RSDs) were below 3.93%, measured at low, medium, and high concentrations. Moreover, the positive sample analysis results indicated that CaHMB was detected on 10 real special medical formula food and sports nutrition food products, the contents of which were generally consistent with their labeled values, with measured values ranging from 97.1 % to 119 % of the labeled values. These results suggested that the developed highly sensitive and specific method is highly feasible for monitoring of the target analyte in special medical formula food and sports nutrition food.

Simultaneous determination of 21 perfluorinated and polyfluoroalkyl substances in plant oils by ultra-high performance liquid chromatography-triple quadrupole mass spectrometry

Edible plant oils are a key component of the daily human diet, and the quality and safety of plant oils are related to human health. Perfluorinated and polyfluoroalkyl substances (PFASs) are pollutants that can contaminate plant oil through the processing of raw materials or exposure to materials containing these substances. Thus, establishing a sensitive and accurate analytical method for the determination of PFASs is critical for ensuring the safety of plant oils. In this study, a method based on acetonitrile extraction and solid phase extraction purification combined with ultra-high performance liquid chromatography-triple quadrupole mass spectrometry (UHPLC-MS/MS) was developed for the simultaneous determination of 21 PFASs, including perfluorocarboxylic acids, perfluoroalkyl sulfonic acids, and fluorotelomer sulfonic acids, in edible plant oils. The chromatographic conditions and MS parameters were optimized, and the influences of the extraction solvents and purification method were systematically studied. Plant oil samples were directly extracted with acetonitrile and purified using a weak anion-exchange (WAX) column. The 21 target PFASs were separated on a reversed-phase C18 chromatographic column and detected using a triple quadrupole mass spectrometer with an electrospray ionization source. The mass spectrometer was operated in negative-ion mode. The target compounds were analyzed in multiple reaction monitoring (MRM) mode and quantified using an internal standard method. The results demonstrated that the severe interference observed during the detection of PFASs in the co-extracted substances was completely eliminated after the extraction mixture was purified using a WAX column. The 21 target PFASs showed good linearity in their corresponding ranges, with correlation coefficients greater than 0.995. The limits of detection (LODs) and limits of quantification (LOQs) of the method were in the range of 0.004-0.015 and 0.015-0.050 μg/kg, respectively. The recoveries ranged from 95.6% to 115.8%, with relative standard deviations (RSDs) in the range of 0.3%-10.9% (n=9). The established method is characterized by simple sample pretreatment, good sensitivity, high immunity to interferences, and good stability, rendering it suitable for the rapid analysis and accurate determination of typical PFASs in edible plant oils.

Determination of calcium β-hydroxy-β-methyl butyrate content in milk and dairy products by solid-phase extraction and high performance liquid chromatography

In this paper, an analytical method based on solid-phase extraction (SPE) purification and high-performance liquid chromatography method (HPLC) was developed for the first time to determine the content of calcium β-hydroxy-β-methyl butyrate (CaHMB) in milk and dairy products. The quantitative detection was performed by HPLC with diode array detector (DAD) under external standard method. The limit of quantification (LOQ), calculated as 10 times the standard deviation, was 0.10 g/100 g. The average recoveries were in the range of 92.40–103.00 %, with relative standard deviations (RSDs) of 1.25–3.77 %, measured at three concentration levels. The real sample analysis results showed that CaHMB was detected in infant formula, formulated milk powder, and milkshake samples, the contents of which were in the range of 0.60–8.66 g/100 g, respectively. The developed method features good purification effect, good separation specificity, good repeatability, accuracy and reliability, and can meet the content determination of CaHMB in milk and dairy products.

A rapid solid-phase extraction purification combined with UPLC[sbnd]MS/MS used for simultaneous determination of eight tetracyclines and three metabolite in chicken and pork

A method for rapid detection and identification of 8 tetracyclines (TCs) and 3 metabolite residues in chicken and pork was established and verified by combining rapid solid-phase extraction (SPE) technology with ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLCMS/MS). After a sample was extracted, it was purified with a PRiME HLB cartridge, and the cartridge did not need to be activated, balanced, or eluted. The filtrate was dried under nitrogen, redissolved, and subsequently analyzed via UPLCMS/MS. The limits of detection for chicken and pork were 0.05–0.48 μg/kg and 0.05–0.52 μg/kg, respectively. The limits of quantification were 0.16–1.61 μg/kg and 0.16–1.75 μg/kg, respectively. The recoveries were 85.15%–107.50% and 84.21%–106.37%, respectively. The established method was suitable for qualitative and quantitative analyses of TCs and their metabolite residues in chicken and pork and has been used for the detection of TC in chicken and pork samples from local markets.

Organ-level distribution tandem mass spectrometry analysis of three structural types of brassinosteroids in rapeseed.

Brassinosteroids (BRs) are a class of naturally occurring steroidal phytohormones mediating a wide range of pivotal developmental and physiological functions throughout the plant's life cycle. Therefore, it is of great significance to determine the content and the distribution of BRs in plants.Regretfully, although a large number of quantitative methods for BRs by liquid chromatography-tandem mass spectrometry (LC-MS/MS) have been reported, the in planta distribution of BRs is still unclear because of their lower contents in plant tissues and the lack of effective ionizable groups in their chemical structures. We stablished a novel analytical method of BRs based on C18 cartridge solid-phase extraction (SPE) purification, 4-(dimethylamino)-phenylboronic acid (DMAPBA) derivatization, and online valve-switching system coupled with ultra-high performance liquid chromatography-electro spray ionization-triple quadrupole mass spectrometry (UHPLC-ESI-MS/MS). This method has been used to quantify three structural types of BRs (epibrassinolide, epicastasterone, and 6-deoxo-24-epicastaster one) in different organs of Brassica napus L. (rapeseed). We obtained the contents of three structural types of BRs in various organ tissues of rapeseed. The contents of three BRs in rapeseed flowers were the highest, followed by tender pods. The levels of three BRs all decreased during the maturation of the organs. We outlined the spatial distribution maps of three BRs in rapeseed based on these results, so as to understand the spatial distribution of BRs at the visual level. Our results provided useful information for the precise in situ localization of BRs in plants and the metabolomic research of BRs in future work. The in planta spatial distribution of BRs at the visual level has been studied for the first time.

Simple Synthesis of [18F] AV-45 and its Clinical Application in the Diagnosis of Alzheimer's Disease.

[18F] AV-45 can be produced in a simple, stable, and repeatable manner on the Tracerlab FXF-N platform using a self-editing synthetic procedure and solid-phase extraction purification method. This technique is applied to positron emission tomography (PET) imaging of Alzheimer's disease (AD) to observe its distribution and characteristics in various brain regions and its diagnostic efficiency for the disease. The precursor was subjected to nucleophilic radiofluorination at 120°C in anhydrous dimethyl sulfoxide, followed by acid hydrolysis of the protecting groups. The neutralized reaction mixture was purified by solid phase extraction to obtain a relatively pure [18F] AV-45 product with a high specific activity. A total of 10 participants who were diagnosed with Alzheimer's disease (AD group) and 10 healthy controls (HC group) were included retrospectively. All of them underwent [18F] AV-45 brain PET/CT imaging. The distribution of [18F] AV-45 in the AD group was analyzed visually and semi-quantitatively. Six consecutive radiochemical syntheses were performed in this experiment. The average production time of [18F] AV-45 was 52 minutes, the radiochemical yield was 14.2 % ± 2.7% (n = 6), and the radiochemical purity was greater than 95%. When used with PET/CT imaging, the results of the visual analysis indicated increased [18F] AV-45 radioactivity uptake in the frontal, temporal, and parietal lobes in AD patients. Semiquantitative analysis showed the highest diagnostic efficacy in the posterior cingulate gyrus compared with other brain regions (P < 0.001). Intravenous [18F] AV-45 was successfully prepared on the Tracerlab FXF-N platform by solid-phase extraction of crude product and automated radiochemical synthesis. PET/CT imaging can be used to diagnose and evaluate AD patients and provide a more robust basis for clinicians to diagnose AD.

Advancements in Microfluidic Cassette-Based iMiDEV™ Technology for Production of L-[11C]Methionine and [11C]Choline.

Microfluidic technology is a highly efficient technique used in positron emission tomography (PET) radiochemical synthesis. This approach enables the precise control of reactant flows and reaction conditions, leading to improved yields and reduced synthesis time. The synthesis of two radiotracers, L-[11C]methionine and [11C]choline, was performed, using a microfluidic cassette and an iMiDEVTM module by employing a dose-on-demand approach for the synthesis process. We focused on optimizing the precursor amounts and radiosynthesis on the microfluidic cassette. L-[11C]methionine and [11C]choline were synthesized using a microreactor filled with a suitable resin for the radiochemical reaction. Trapping of the [11C]methyl iodide, its reaction, and solid-phase extraction purification were performed on a microreactor, achieving radiochemical yields of >80% for L-[11C]methionine and >60% for [11C]choline (n = 3). The total synthesis time for both the radiotracers was approximately 20 min. All quality control tests complied with the European Pharmacopeia standards. The dose-on-demand model allows for real-time adaptation to patient schedules, making it suitable for preclinical and clinical settings. Precursor optimization enhanced the cost efficiency without compromising the yield. The importance of dose-on-demand synthesis and optimized precursor utilization to produce L-[11C]methionine and [11C]choline was emphasized in this study. The results demonstrated the feasibility of dose-on-demand adaptations for clinical applications with reduced precursor quantities and high radiochemical yields.

Determination of 60 Food-Borne Stimulant Drug Residues in Animal-Derived Foods by Solid-Phase Extraction Purification and Ultra-High-Performance Liquid Chromatography-Quadrupole/Orbitrap High-Resolution Mass Spectrometry

A method for the rapid screening and confirmation of 60 food-borne stimulants in animal-derived foods was developed using the ultra-high-performance liquid chromatography-quadrupole/orbitrap high-resolution mass spectrometry (UPLC-Q/Orbitrap HRMS). After enzymatic hydrolysis at 37°C for 16 h, the samples were extracted with acetonitrile solution. The extraction solution was purified by PRiME HLB pass-through solid-phase extraction cartridge and redissolved by nitrogen blowing. The target compounds of reconstitution fluid were separated by Hypersil GOLD™ VANQUISH column (2.1 mm × 100 mm, 1.9 μm). The raw data were collected for the target compounds in Full Scan-ddMS2 mode, and then the Quan Browser module under Xcalibur software can be used to analyze the quantitative results of the samples. The combination of Tracefinder and mzVault software can realize the qualitative screening and confirmation of the samples. The results showed that the relative deviation of the exact mass of the 60 food-borne stimulants was less than 5.0 × 10−6, which had a good linear relationship in the corresponding concentration, and the correlation coefficient (R2) was greater than 0.9966. The detection limit ranged from 0.05 to 0.5 μg/kg. The quantification limit ranged from 0.1 to 1 μg/kg. The method recoveries ranged from 70.2% to 111.9% with relative standard deviations of 0.05% to 9.00% (n = 6). The method is easy to operate, covers a wide range of targets, and has high efficiency and accuracy. It is suitable for rapid screening and confirmation of various food-derived stimulants in animal-derived foods and provides assistance for food safety in the major events.

Microfluidic-based production of [68Ga]Ga-FAPI-46 and [68Ga]Ga-DOTA-TOC using the cassette-based iMiDEV™ microfluidic radiosynthesizer

BackgroundThe demand for 68Ga-labeled radiotracers has significantly increased in the past decade, driven by the development of diversified imaging tracers, such as FAPI derivatives, PSMA-11, DOTA-TOC, and DOTA-TATE. These tracers have exhibited promising results in theranostic applications, fueling interest in exploring them for clinical use. Among these probes, 68Ga-labeled FAPI-46 and DOTA-TOC have emerged as key players due to their ability to diagnose a broad spectrum of cancers ([68Ga]Ga-FAPI-46) in late-phase studies, whereas [68Ga]Ga-DOTA-TOC is clinically approved for neuroendocrine tumors. To facilitate their production, we leveraged a microfluidic cassette-based iMiDEV radiosynthesizer, enabling the synthesis of [68Ga]Ga-FAPI-46 and [68Ga]Ga-DOTA-TOC based on a dose-on-demand (DOD) approach.ResultsDifferent mixing techniques were explored to influence radiochemical yield. We achieved decay-corrected yield of 44 ± 5% for [68Ga]Ga-FAPI-46 and 46 ± 7% for [68Ga]Ga-DOTA-TOC in approximately 30 min. The radiochemical purities (HPLC) of [68Ga]Ga-FAPI-46 and [68Ga]Ga-DOTA-TOC were 98.2 ± 0.2% and 98.4 ± 0.9%, respectively. All the quality control results complied with European Pharmacopoeia quality standards. We optimized various parameters, including 68Ga trapping and elution, cassette batches, passive mixing in the reactor, and solid-phase extraction (SPE) purification and formulation. The developed synthesis method reduced the amount of precursor and other chemicals required for synthesis compared to conventional radiosynthesizers.ConclusionsThe microfluidic-based approach enabled the implementation of radiosynthesis of [68Ga]Ga-FAPI-46 and [68Ga]Ga-DOTA-TOC on the iMiDEV™ microfluidic module, paving the way for their use in preclinical and clinical applications. The microfluidic synthesis approach utilized 2–3 times less precursor than cassette-based conventional synthesis. The synthesis method was also successfully validated in a similar microfluidic iMiDEV module at a different research center for the synthesis of [68Ga]Ga-FAPI-46 with limited runs. Our study demonstrated the potential of microfluidic methods for efficient and reliable radiometal-based radiopharmaceutical synthesis, contributing valuable insights for future advancements in this field and paving the way for routine clinical applications in the near future.

Valorization of black grape pomace by pressurized hot water extraction and hydrolysis: Real-time online and in-line monitoring

The primary aim of this study was to maximize the value of black grape pomace by harnessing innovative and environmentally friendly extraction and hydrolysis technology on the biorefinery concept. This automated system seamlessly integrates pressurized hot water extraction (PHWE) and sequential subcritical water hydrolysis (SubCWH), complemented by inline purification through solid phase extraction (SPE) and online analysis via high-performance liquid chromatography (HPLC) equipped with photodiode array (PDA) and refractive index (RI) detectors. The results of this investigation revealed the presence of twelve anthocyanins, each exceeding a concentration of 3 mgEC3G gDBGP-1. By summing the concentration of these individual anthocyanins, a total yield of 47.6 mgEC3G gDBGP-1 was achieved, attributed to the utilization of acidified water as the solvent and adherence to optimal process conditions. The newly developed system demonstrated its efficacy in both PHWE and SubCWH of black grape pomace, coupled with inline SPE purification and real-time HPLC analysis of various natural compounds. The real-time monitoring capability facilitated swift and efficient responses, reducing processing time, minimizing solvent consumption, decreasing labor requirements, conserving energy, and mitigating environmental impact.

Design and Optimisation of Sustainable Sample Treatments Based on Ultrasound-Assisted Extraction and Strong Cation-Exchange Purification with Functionalised SBA-15 for Opium Alkaloids in Ground Poppy Seeds.

An analysis methodology was optimised and validated for the quantification of opium alkaloids (OAs) in ground poppy seeds. This involved ultrasound-assisted extraction (UAE) and solid-phase extraction (SPE) purification before analysis using a high-performance liquid chromatography mass spectrometry detector (HPLC-MS/MS). UAE was optimised through the design of experiments with three factors and a three-level full factorial design. For SPE optimisation, a commercial material was compared with a previously synthesised material of SBA-15 silica functionalised with sulfonic groups (SBA-15-SO3-). The synthesised material demonstrated superior efficiency with only 25 mg and proved to be reusable for up to four cycles. The methodology was properly validated in terms of linearity, limits of detection and quantification, and selectivity. Matrix effects were negligible; adequate recovery values (85-100%) and inter-day and intra-day precision (≤15%) were obtained. The greenness of the method was evaluated with the AGREEprep metric scale, being more environmentally friendly compared to OA analysis methods. Finally, the method was applied to different samples of ground poppy seeds and revealed a concentration of 140 mg/kg of morphine equivalents in one of the samples, surpassing the legislatively established limits by sevenfold. This highlights the need to analyse these types of samples to mitigate potential public health issues.

Determination of ethyl glucuronide in hair and self-reported alcohol consumption in university students.

Young individuals constitute an intriguing population, as their drinking habits are notably shaped by their perception of their peers' alcohol consumption. Nonetheless, excessive alcohol intake can have detrimental effects on academic performance, interpersonal relationships, and the risk and severity of accidents. This study reported the first data involving students enrolled from three universities on a voluntary basis for alcohol consumption evaluation. Alcohol consumption was assessed through questionnaires and EtG quantification in hair (hEtG) carried out by liquid chromatography-mass spectrometry (LC-MS/MS) analysis after a solid-phase extraction (SPE) purification step. The results of our study demonstrated that 77.1% of samples tested negative for hEtG or displayed hEtG ≤ 5pg/mg. Particularly, the student population was not characterized by samples with hEtG indicative of chronic excessive consumption (hEtG ≥ 30pg/mg). No significant association was identified between biological sex, among the degree course/the year attended, nor in relation to BMI or smoking/coffee consumption. Among the obtained results, it was worth noting that the comparison of self-reporting abstinence from tobacco and coffee accounted for 65.3% and 16.7%, respectively, while only 2.8% of the total declared abstinence from alcohol. The current study has uncovered a significant level of interest among students in this analysis and its interpretation. This suggests that implementing public health promotion activities within a university setting could be beneficial.

Determination of 10 carbamate pesticide residues in liquid milk by ultra performance liquid chromatography-tandem mass spectrometry with pass-through solid-phase extraction purification

Carbamates are used in broad-spectrum insecticides and herbicides, and have highly efficient, low-residue, and long-lasting characteristics. However, this type of pesticide exerts mutagenic, teratogenic, carcinogenic, and other adverse effects, and its frequent use can exceed the recommended scope and limits. Research on the determination of carbamate pesticides mainly focuses on foods of plant origin and pays less attention to foods of animal origin. The methods for carbamate determination described in the current national standards have complicated operating procedures and low efficiency. Therefore, highly efficient and accurate methods for carbamate detection in milk must be established. In this work, a rapid method based on pass-through solid-phase extraction (SPE) purification coupled with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for the simultaneous determination of 10 carbamate pesticides in liquid milk. The pretreatment and instrument methods were systematically optimized. The milk sample was extracted with acetonitrile, and then purified using a Captiva EMR-Lipid filtration kit. The purified extract was separated on an ACQUITY UPLC BEH C18 column with mobile phase of methanol and 0.1% formic acid aqueous solution in gradient elution. The flow rate was 0.3 mL/min. Column temperature was 35 ℃. Quantitative analysis was performed using the external standard method with matrix matching curves. The 10 carbamate pesticides showed good linear relationships in the mass concentration range of 2-200 μg/L, with correlation coefficients greater than 0.999. The limits of detection (LODs) and quantification (LOQs) for the 10 carbamate pesticides were 0.045-0.23 and 0.15-0.77 μg/kg, respectively. Recovery tests were conducted using the blank-matrix method at three spiked levels of 15, 50, and 100 μg/kg, and good recoveries for the 10 carbamate pesticides were obtained. In particular, the recoveries for the three spiked levels of 15, 50, and 100 μg/kg were 68.7%-93.3% with relative standard deviations (RSDs) of 1.8%-8.0%. The proposed method is efficient, convenient, accurate, and suitable for the rapid detection of the 10 carbamate pesticides in liquid milk. Compared with the conventional NH2 and ENVITM-18 SPE columns used in the national standard determination method, the proposed method demonstrated better purification effects. The recoveries for aldicarb sulfoxide, aldicarb sulfone, methomyl, and carbaryl after purification using the Captiva EMR-Lipid kit increased from 60% to 80%. Thus, the proposed method is suitable for targets with strong polarity and gives measurement results with good repeatability and accuracy.

Determination of tolfenpyrad residues in green tea by GC-MS/MS based on acetonitrile extractant, dispersion solid phase extraction purification

Green tea is one of people’s favorite drinks. However, pesticide residues in green tea can cause harm to the human body, and therefore, detection of pesticide residues in green tea is very important. In recent years, the detection of pesticide residues in tea has become a research hotspot. In this paper, a gas chromatography-mass spectrometry/mass spectrometry (GC-MS/MS) detection method of tolfenpyrad pesticide residues in green tea was established by using acetonitrile extractant, dispersive solid-phase extraction purification, temperature programming and application retention time lock with the database. After the sample was extracted with acetonitrile, then the sample was purified by QuEChERS extraction purification tube, afterward isomer B was used as the internal standard for the determination by multiple reaction monitoring mode (MRM) of GC-MS/MS. The results indicated that the experimental data accorded with the criterion on quality control of laboratoris(chemical testing of food), and the requirements of recovery, calibration curve, precision.This method was used to detect tolfenpyrad residues in actual green tea samples in multiple batches, and the satisfactory results were obtained.

Determination of bisphenols in sediment by accelerated solvent extraction and solid-phase extraction purification coupled with ultra performance liquid chromatography-tandem mass spectrometry

Bisphenols are endocrine disruptors that are characterized with bioaccumulation, persistence, and estrogenic activity. Even low contents of bisphenols can exert adverse effects on human health and the ecological environment. Herein, a method combining accelerated solvent extraction and solid-phase extraction purification with ultra performance liquid chromatography-tandem mass spectrometry was developed for the accurate detection of bisphenol A (BPA), bisphenol B (BPB), bisphenol F (BPF), bisphenol S (BPS), bisphenol Z (BPZ), bisphenol AF (BPAF), and bisphenol AP (BPAP) in sediments. The mass spectrometric parameters of the seven bisphenols were optimized, and the response values, separation effects, and chromatographic peak shapes of the target compounds were compared under three different mobile phase conditions. The sediment samples were pretreated by accelerated solvent extraction, and orthogonal tests were used to optimize the extraction solvent, extraction temperature, and cycle number. The results showed that the use of 0.05% (v/v) ammonia and acetonitrile as the mobile phase for gradient elution could rapidly separate the seven bisphenols on an Acquity UPLC BEH C18 column (100 mm×2.1 mm, 1.7 μm). The gradient program was as follows: 0-2 min, 60%A; 2-6 min, 60%A-40%A; 6-6.5 min, 40%A; 6.5-7 min, 40%A-60%A; 7-8 min, 60%A. Orthogonal experiments indicated that the optimal extraction conditions were as follows: extraction solvent of acetonitrile, extraction temperature of 100 ℃, and cycle number of three. The seven bisphenols showed good linearity in the range of 1.0-200 μg/L, with correlation coefficients (r2) greater than 0.999, and the limits of detection were 0.01-0.3 ng/g. The recoveries for the seven bisphenols ranged from 74.9% to 102.8% at three spiking levels (2.0, 10, 20 ng/g), with relative standard deviations ranging from 6.2% to 10.3%. The established method was applied to detect the seven bisphenols in sediment samples collected from Luoma Lake and its inflow rivers. BPA, BPB, BPF, BPS, and BPAF were detected in the sediments of the lake, and BPA, BPF, and BPS were detected in the sediments of its inflow rivers. The detection frequency of BPA and BPF was 100%, and the contents of these bisphenols in the sediment were 11.9-38.0 ng/g and 11.0-27.3 ng/g, respectively. The developed method is simple, rapid with high accuracy and precision, and is suitable for the determination of the seven bisphenols in sediment.

Determination of new glucocorticoid called clobetasol acetate in cosmetics by ultra performance liquid chromatography-tandem mass spectrometry

At present, new prohibited substances are becoming more common illegal additions in cosmetics. Clobetasol acetate is a new glucocorticoid, which is not covered in the current national standards and is a homologue of clobetasol propionate. A method was established for the determination of clobetasol acetate as a new glucocorticoid (GC) in cosmetics by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Five common cosmetic matrices were suitable for this new method: creams, gels, clay masks, masks and lotions. Four pretreatment methods were compared: direct extraction by acetonitrile, PRiME pass-through column purification, solid-phase extraction (SPE) purification, and QuEChERS purification. Further, the effects of different extraction efficiencies of the target compound, such as extraction solvents and extraction time, were investigated. The MS parameters, such as ion mode, cone voltage and collision energy of ion pairs of the target compound, were optimized. The chromatographic separation conditions and response intensities of the target compound in different mobile phases were compared. Based on the experimental results, the optimal extraction method was determined to be direct extraction, wherein the samples were vortex dispersed with acetonitrile, ultrasonic extraction over 30 min and filtered by a 0.22 μm organic millipore filter, and then the samples were detected by UPLC-MS/MS. The concentrated extracts were separated on a Waters CORTECS C18 column (150 mm×2.1 mm, 2.7 μm), where the water and acetonitrile were used as the mobile phases for gradient elution. The target compound was detected with the multiple reaction monitoring (MRM) mode under electrospray ionization and positive ion scanning (ESI+). Quantitative analysis was performed by matrix matching standard curve. Under the optimum conditions, the target compound had good linear fitting in the range of 0.9-37 μg/L. The linear correlation coefficient (R2) was greater than 0.99, the limit of quantification (LOQ) of the method was 0.09 μg/g and the limit of detection (LOD) was 0.03 μg/g for these five different cosmetic matrices. The recovery test was conducted under three spiked levels: 1, 2 and 10 times of LOQ. The recoveries of the tested substance were between 83.2% and 103.2% in these five cosmetic matrices, and the relative standard deviations (RSDs, n=6) were between 1.4% and 5.6%. This method was used to screen cosmetic samples of different matrix types, and a total of five positive samples were found, in which the content range of clobetasol acetate was from 1.1 to 48.1 μg/g. In conclusion, the method is simple, sensitive and reliable, and is suitable for high-throughput qualitative and quantitative screening, and the analysis of cosmetics with different matrix types. Moreover, the method provides crucial technical support and a theoretical basis for the establishment of feasible detection standards for clobetasol acetate in China, as well as for the control of the compound in cosmetics. This method has important practical significance to implement management measures of illegal additions in cosmetics.

Development of PET Tracers of Glutamine Metabolism

The labeling of amino acids with positron-emitting radionuclides (such as fluorine-18) has been a widely used approach for the imaging of tumors as it often provides higher diagnostic accuracy than what is observed with [18F]FDG. In particular, PET tracers of glutamine metabolism have garnered significant attention in recent years. O-(2-[18F]fluoroethyl-L-tyrosine (18F-FET) is a promising PET tracer in this regard and is currently under investigation at Indiana University (IU) through an expanded access IND for patients with brain malignancies. Clinical production of 18F-FET at IU previously required the use of HPLC for purification, following the reaction of fluorine-18 with the precursor molecule for FET. While this method has been successful in removing undesirable impurities and byproducts, HPLC significantly increases synthesis time and is a common failure point in the synthesis of FET on our current radiochemistry module. To address this issue, we aimed to deploy a solid-phase-extraction (SPE) method for the purification of FET, thereby eliminating the need for HPLC purification. Several methods for the SPE purification of FET have been previously reported; however, none of these strategies afforded pure [18F]FET on our synthesis module, thus development of new methods was required.&#x0D; While several tracers capable of measuring different aspects of glutamine metabolism have been evaluated in both preclinical and clinical studies, there are metabolic liabilities that limit their utility and complicate data analysis. [18F]-4F-glutamine is one such tracer that has shown promise but has limitations due to undesirable metabolism in vivo. Herein we report our progress towards an improved synthesis of [18F]FET for ongoing clinical studies as well as our progress towards the development of a novel tracer that would address metabolic liabilities associated with currently available PET tracers of glutamine metabolism.

Beneficial regulation of vitamin D3-rich extract from the processing by-products of Penaeus sinensis on preosteoblastic MC3T3-E1 cells and improvement of bone health in VD-deficient mice.

Vitamin D (VD) plays an important role in preventing osteoporosis. However, knowledge of the osteogenic effect of VD3 from shrimp processing by-products is limited. In this study, a VD3-rich extract from Penaeus sinensis processing by-products was prepared by saponification and liquid-liquid extraction combined with solid phase extraction for purification. The activity of purified VD3-rich extract (PPs-VD3) on MC3T3-E1, a preosteoblastic cell line, was determined. Furthermore, the improvement effect of PPs-VD3 on bone health of VD-deficient mice was investigated. PPs-VD3 stimulated the proliferation and differentiation of MC3T3-E1 cells. Compared to the same concentration of the VD3 standard, mineralization of MC3T3-E1 cells increased after 14 d or 21 d of PPs-VD3 treatment. Western blotting showed that PPs-VD3 significantly upregulated the protein levels of bone morphogenetic protein 2 and runt-related transcription factor 2 compared to the VD3 standard. Furthermore, PPs-VD3 treatment activated the receptor activator of nuclear factor-kappa B ligand (RANKL)/osteoprotegerin (OPG) signaling pathway in MC3T3-E1 cells, especially increased OPG expression was detected at day 3 to day 14 compared to the VD3 standard treatment. More than ten medium and long chain fatty acids were detected in PPs-VD3, of which n-3 polyunsaturated fatty acids (PUFA) constituted 38.83 ± 8.61%, and the n-3/n-6 PUFA ratio in PPs-VD3 was 2.84 ± 0.23. The femoral trabeculae number and thickness of VD-deficient mice increased after 3 weeks of PPs-VD3 treatment. The changes of parameters associated with bone resorption including parathyroid hormone, bone mineral density and tartrate resistant acid phosphatase revealed the contribution of PPs-VD3 treatment in improving bone remodeling in VD-deficient mice. Our results suggest that PPs-VD3 could have potential prospects in alleviating osteoporosis or promotion of bone health.

Automated Optimized Synthesis of [18F]FLT Using Non-Basic Phase-Transfer Catalyst with Reduced Precursor Amount.

3′-deoxy-3′-[18F]fluorothymidine ([18F]FLT) is a positron emission tomography (PET) tracer useful for tumor proliferation assessment for a number of cancers, particularly in the cases of brain, lung, and breast tumors. At present [18F], FLT is commonly prepared by means of the nucleophilic radiofluorination of 3-N-Boc-5′-O-DMT-3′-O-nosyl thymidine precursor in the presence of a phase-transfer catalyst, followed by an acidic hydrolysis. To achieve high radiochemical yield, relatively large amounts of precursor (20−40 mg) are commonly used, leading to difficulties during purification steps, especially if a solid-phase extraction (SPE) approach is attempted. The present study describes an efficient method for [18F]FLT synthesis, employing tetrabutyl ammonium tosylate as a non-basic phase-transfer catalyst, with a greatly reduced amount of precursor employed. With a reduction of the precursor amount contributing to lower amounts of synthesis by-products in the reaction mixture, an SPE purification procedure using only two commercially available cartridges—OASIS HLB 6cc and Sep-Pak Alumina N Plus Light—has been developed for use on the GE TRACERlab FX N Pro synthesis module. [18F]FLT was obtained in radiochemical yield of 16 ± 2% (decay-corrected) and radiochemical purity >99% with synthesis time not exceeding 55 min. The product was formulated in 16 mL of normal saline with 5% ethanol (v/v). The amounts of chemical impurities and residual solvents were within the limits established by European Pharmacopoeia. The procedure described compares favorably with previously reported methods due to simplified automation, cheaper and more accessible consumables, and a significant reduction in the consumption of an expensive precursor.

Comparison of solid-phase extraction methods for efficient purification of phosphopeptides with low sample amounts

Efficient phosphoproteomic analysis of small amounts of biological samples (e.g. tissue biopsies) requires carefully selected enrichment and purification steps prior to the nanoflow HPLC-MS/MS analysis. Solid-phase extraction (SPE) is one of the most commonly used approaches for sample preparation. Several stationary phases are available for peptide SPE purification, however, most of the published methods are not optimized to provide good recoveries of phosphorylated peptides. Our goal was to investigate the performance of 13 self-packed and 3 commercial centrifugal SPE cartridges/spin tips, thus enhancing the efficiency of the phosphoproteomic analysis of small amounts of complex protein mixtures. Eight reversed-phase (RP), five graphite, two ion-exchange, and one hydrophilic-lipophilic balance (HLB) stationary phase were evaluated. Two RP, one graphite, and the HLB self-packed centrifugal SPE tips provided excellent results for the purification of 1 µg tissue and cell line digests. Using these methods, the sample loss was significantly reduced compared to one of the commercial SPE methods, 22-58% more unique phosphopeptides were identified, and the recovery was higher by 132-155%.