Formic Acid Aqueous Solution Research Articles

A simple HPLC-DAD method for analysis of phenolic acids: Addition effect of a hydrophilic deep eutectic solvent to the mobile phase

AbstractThe analysis of phenolic acids (PAs) is of great importance, because they are frequently present in natural products and their derivatives, and these compounds also have multiple beneficial effects to human health. This work is focusing on the separation of seven PAs (caffeic acid, coumaric acid, gallic acid, ferulic acid, protocatechuic acid, sinapic acid, and syringic acid), in a reversed-phase liquid chromatographic (RP-HPLC) isocratic method using a hydrophilic deep eutectic solvent (DES) as a mobile phase additive. The analysis was carried out with a diode array detector. The used DES was composed by choline chloride and glycerol, and it was characterized by infrared spectroscopy. The combination of choline chloride:glycerol (1:4) added at 0.25% to mobile phase composed of 0.15% formic acid aqueous solution and methanol (80:20), showed the best separation for target analytes. The new proposed method was validated, and results indicated that the proposed method is linear, selective for almost all analytes, provided high sensitivity with limit of detection ranges from 0.009 to 0.023 mg mL−1, and has satisfactory precision and accuracy, with values of relative standard deviation of 0.24–2.65% and recoveries of 97.97–109%, respectively. Additionally, this method was successfully applied to simultaneous determination of phenolic acids in three kinds of samples of powder to prepare lemon flavour drink enriched with black tea extract.

Hydrogen Production from Formic Acid by In Situ Generated Ni/CdS Photocatalytic System under Visible Light Irradiation.

Simple and practical noble-metal-free catalyzed hydrogen production from sustainable resources, such as renewable formic acid, is highly desirable. Herein, the development of an efficient photocatalytic hydrogen production from aqueous solution of formic acid using in situ generated Ni/CdS photocatalytic system was described. CdS-Cys (Cys=l-cysteine) quantum dots (QDs) acting as photocatalyst with Ni(OAc)2 as H2 production catalyst precursor, a 94 % yield was obtained within 5 h under visible light irradiation at 50 °C. The average rate of H2 production reached up to 282 μmol mg-1 h-1 with 99.8 % H2 selectivity. Mechanistic studies indicate cooperation of dynamic quenching and static quenching of CdS-Cys QDs by Ni(OAc)2 . Especially, Ni0 , generated in the dynamic quenching, accelerated the electron transfer by acting as an electron outlet and enhancing the stability of CdS to slow down the photocorrosion distinctly, delivering efficient H2 production with high selectivity. Our study will inspire exploration of various efficient non-noble-metal catalysts for practical H2 production from bio-based formic acid.

Simultaneous determination of 22 antibiotics in environmental water samples by solid phase extraction-high performance liquid chromatography-tandem mass spectrometry

The widespread and frequent use of antibiotics to treat diseases or encourage animal growth has resulted in their persistence and accumulation in water, soil, and sediments. As a typical emerging pollutant in the environment, antibiotics have become an important research focus in recent years. Antibiotics are commonly found at trace levels in water environments. Unfortunately, the determination of various types of antibiotics, all of which exhibit different physicochemical properties, remains a challenging endeavor. Thus, developing pretreatment and analytical techniques to achieve the rapid, sensitive, and accurate analysis of these emerging contaminants in various water samples is an essential undertaking.In this paper, a solid phase extraction-high performance liquid chromatography-tandem mass spectrometry (SPE-HPLC-MS/MS) method for the simultaneous determination of 22 antibiotics including 4 penicillins, 12 quinolones and 6 macrolides in environmental water samples was developed. Based on the characteristics of the screened antibiotics and sample matrix, the pretreatment method was optimized, focusing on the SPE column, pH of the water sample, and amount of ethylene diamine tetra-acetic acid disodium (Na2EDTA) added to the water sample. Prior to extraction, a 200 mL water sample was added with 0.5 g of Na2EDTA and pH-adjusted to 3 using sulfuric acid or sodium hydroxide solution. Water sample enrichment and purification were achieved using an HLB column. HPLC separation was carried out on a C18 column (100 mm×2.1 mm, 3.5 μm) via gradient elution with a mobile phase composed of acetonitrile and 0.15% (v/v) formic acid aqueous solution. Qualitative and quantitative analyses were performed on a triple quadrupole mass spectrometer in multiple reaction monitoring mode using an electrospray ionization source. The results showed correlation coefficients greater than 0.995, indicating good linear relationships. The method detection limits (MDLs) and limits of quantification (LOQs) were in the ranges of 2.3-10.7 ng/L and 9.2-42.8 ng/L, respectively. The recoveries of target compounds in surface water at three spiked levels ranged from 61.2% to 157%, with relative standard deviations (RSDs) of 1.0%-21.9%. The recoveries of target compounds in wastewater at three spiked levels were 50.1%-129%, with RSDs of 1.2%-16.9%. The method was successfully applied to the simultaneous determination of antibiotics in reservoir water, surface water, sewage treatment plant outfall, and livestock wastewater. Most of the antibiotics were detected in watershed and livestock wastewater. Lincomycin was detected in 10 surface water samples, with a detection frequency of 90%, and ofloxacin showed the highest contents (127 ng/L) in livestock wastewater. Therefore, the present method exhibits excellent performance in terms of MDLs and recoveries compared with previously reported methods. The developed method presents the advantages of small water sample volumes, wide applicability, and fast analysis times; thus, it can be considered a rapid, efficient, and sensitive analytical method with excellent potential for monitoring emergency environmental pollution. The method could also provide a reliable reference for formulating antibiotic residue standards. The results provide strong support for and an improved understanding of the environmental occurrence, treatment, and control of emerging pollutants.

Simultaneous determination of five lignans from Schisandra chinensis by matrix solid-phase dispersion extraction-high performance liquid chromatography

The kidney-shaped, red-colord fruit from the plant, Schisandra chinensis (Turcz.) Baill, which belongs to the Schisandraceae family, is among the most popular remedies used in traditional Chinese medicine. The English name of the plant is "Chinese magnolia vine". It has been used in Asia since ancient times to treat a variety of ailments, including chronic cough and dyspnea, frequent urination, diarrhea, and diabetes. This is because of the wide range of bioactive constituents, such as lignans, essential oils, triterpenoids, organic acids, polysaccharides, and sterols. In some cases, these constituents affects the pharmacological efficacy of the plant. Lignans with a dibenzocyclooctadiene-type skeleton are considered to be the major constituents and main bioactive ingredients of Schisandra chinensis. However, because of the complex composition of Schisandra chinensis, the extraction yields of lignans are low. Thus, it is particularly important to study pretreatment methods used during sample preparation for the quality control of traditional Chinese medicine. Matrix solid-phase dispersion extraction (MSPD) is a comprehensive process involving destruction, extraction, fractionation, and purification. The MSPD method is simple, it requires only a small number of samples and solvents, it does not require any special experimental equipments or instruments, and it can be used to prepare liquid, viscous, semi-solid, solid samples. In this study, a method combining matrix solid-phase dispersion extraction with high performance liquid chromatography (MSPD-HPLC) was established for the simultaneous determination of five lignans (schisandrol A, schisandrol B, deoxyschizandrin, schizandrin B, and schizandrin C) in Schisandra chinensis. The target compounds were separated on a C18 column with a gradient elution of 0.1% (v/v) formic acid aqueous solution and acetonitrile as the mobile phases, and detection was performed at a wavelength of 250 nm. First, the effects of 12 adsorbents, including silica gel, acidic alumina, neutral alumina, alkaline alumina, Florisil, Diol, XAmide, Xion, and the inverse adsorbents, C18, C18-ME, C18-G1, and C18-HC, on the extraction yields of lignans were investigated. Second, effects of the mass of the adsorbent, the type of eluent, and volume of eluent on the extraction yields of lignans were investigated. Xion was chosen as an adsorbent for MSPD-HPLC analysis of lignans from Schisandra chinensis. Optimization of the extraction parameters showed that the MSPD method had a high lignan extraction yield with Schisandra chinensis powder (0.25 g) as a fixed value, Xion as the adsorbent (0.75 g), and methanol as the elution solvent (15 mL). Analytical methods were developed for five lignans from Schisandra chinensis and these methods showed good linearity (correlation coefficients (R2)≥ 0.9999) for each target analyte. The limits of detection and quantification ranged from 0.0089 to 0.0294 μg/mL and 0.0267 to 0.0882 μg/mL, respectively. Lignans were tested at low, medium, and high levels. The average recovery rates were 92.2% to 111.2%, and the relative standard deviations were 0.23% to 3.54%. Both intra-day and inter-day precisions were less than 3.6%. Compared with hot reflux extraction and ultrasonic extraction methods, MSPD has the advantages of combined extraction and purification, being less time-consuming, and requiring lower solvent volumes. Finally, the optimized method was successfully applied to analyze five lignans from Schisandra chinensis samples from 17 cultivation areas.

Identification of chemical components and network pharmacology of Huanglian Decoction based on UPLC-Q-TOF-MS/MS technology

The chemical components of Huanglian Decoction were identified by ultra-performance liquid chromatography-quadrupole-time-of-flight-tandem mass spectrometry(UPLC-Q-TOF-MS/MS) technology. The gradient elution was conducted in Agilent ZORBAX Extend-C_(18) column(2.1 mm×100 mm, 1.8 μm) with the mobile phase of 0.1% formic acid aqueous solution(A)-acetonitrile(B) at a flow rate of 0.3 mL·min~(-1) and the column temperature of 35 ℃. The MS adopted the positive and negative ion mode of electrospray ionization(ESI), and the MS data were collected under the scanning range of m/z 100-1 500. Through high-resolution MS data analysis, combined with literature comparison and confirmation of reference substances, this paper identified 134 chemical components in Huanglian Decoction, including 12 alkaloids, 23 flavonoids, 22 terpenes and saponins, 12 phenols, 7 coumarins, 12 amino acids, 23 organic acids, and 23 other compounds, and the medicinal sources of the compounds were ascribed. Based on the previous studies, 7 components were selected as the index components. Combined with the network pharmacology research and analysis me-thods, the protein and protein interaction(PPI) network information of the intersection targets was obtained through the STRING 11.0 database, and 20 core targets of efficacy were screened out. In this study, UPLC-Q-TOF-MS/MS technology was successfully used to comprehensively analyze and identify the chemical components of Huanglian Decoction, and the core targets of its efficacy were discussed in combination with network pharmacology, which laid the foundation for clarifying the material basis and quality control of Huanglian Decoction.

Investigation of the chemical components of Ciwujia injection using ultra-high performance liquid chromatography-quadrupole-electrostatic field orbitrap high-resolution mass spectrometry

Ciwujia injection is commonly used to treat cerebrovascular and central nervous system diseases in clinical practice. It can significantly improve blood lipid levels and endothelial cell function in patients with acute cerebral infarction and promote the proliferation of neural stem cells in cerebral ischemic brain tissues. The injection has also been reported to have good curative effects on cerebrovascular diseases, such as hypertension and cerebral infarction. At present, the material basis of Ciwujia injection remains incompletely understood, and only two studies have reported dozens of components, which were determined using high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF MS). Unfortunately, the lack of research on this injection restricts the in-depth study of its therapeutic mechanism.In the present study, a qualitative method based on ultra-high performance liquid chromatography-quadrupole-electrostatic field orbitrap high-resolution mass spectrometry (UHPLC-Q/Orbitrap HRMS) was developed to analyze the chemical components of Ciwujia injection. Separation was performed on a BEH Shield RP18 column (100 mm×2.1 mm, 1.7 μm) using 0.1% formic acid aqueous solution (A) and acetonitrile (B) as the mobile phases, and gradient elution was performed as follows: 0-2 min, 0%B; 2-4 min, 0%B-5%B; 4-15 min, 5%B-20%B; 15-15.1 min, 20%B-90%B; 15.1-17 min, 90%B. The flow rate and column temperature were set to 0.4 mL/min and 30 ℃ respectively. MS1 and MS2 data were acquired in both positive- and negative-ion modes using a mass spectrometer equipped with an HESI source. For data post-processing, a self-built library including component names, molecular formulas, and chemical structures was established by collecting information on the isolated chemical compounds of Acanthopanax senticosus. The chemical components of the injection were identified by comparison with standard compounds or MS2 data in commercial databases or literature based on precise relative molecular mass and fragment ion information. The fragmentation patterns were also considered. For example, the MS2 data of 3-caffeoylquinic acid (chlorogenic acid), 4-caffeoylquinic acid (cryptochlorogenic acid), and 5-caffeoylquinic acid (neochlorogenic acid) were first analyzed. The results indicated that these compounds possessed similar fragmentation behaviors, yielding product ions at m/z 173 and m/z 179 simultaneously. However, the abundance of the product ion at m/z 173 was much higher in 4-caffeoylquinic acid than in 5-caffeoylquinic acid or 3-caffeoylquinic acid, and the fragment signal at m/z 179 was much stronger for 5-caffeoylquinic acid than for 3-caffeoylquinic acid. Four caffeoylquinic acids were identified using a combination of abundance information and retention times. MS2 data in commercial database and literature were also used to identify unknown constituents. For example, compound 88 was successfully identified as possessing a relative molecular mass and neutral losses similar to those of sinapaldehyde using the database, and compound 80 was identified as salvadoraside because its molecular and fragmentation behaviors were consistent with those reported in the literature. A total of 102 constituents, including 62 phenylpropanoids, 23 organic acids, 7 nucleosides, 1 iridoid, and 9 other compounds, were identified. The phenylpropanoids can be further classified as phenylpropionic acids, phenylpropanols, benzenepropanals, coumarins, and lignans. Among the detected compounds, 16 compounds were confirmed using reference compounds and 65 compounds were identified in Ciwujia injection for the first time. This study is the first to report the feasibility of using the UHPLC-Q/Orbitrap HRMS method to quickly and comprehensively analyze the chemical components of Ciwujia injection. The 27 newly discovered phenylpropanoids provide further material basis for the clinical treatment of neurological diseases and new research targets for the in-depth elucidation of the pharmacodynamic mechanism of Ciwujia injection and its related preparations.

Determination of 14 paralytic shellfish toxins in plasma and urine by ultra-high performance liquid chromatography-tandem mass spectrometry

The detection of paralytic shellfish toxins in human biological matrices is important for the diagnosis and treatment of food poisoning caused by them. An ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was established for the determination of 14 paralytic shellfish toxins in plasma and urine. The effect of solid phase extraction (SPE) cartridges was also investigated and the pretreatment and chromatographic conditions were optimized. Under these optimal conditions, 0.2 mL water, 0.4 mL methanol, and 0.6 mL acetonitrile were successively added to plasma and urine samples for extraction. The supernatants from plasma extraction were subjected to an UHPLC-MS/MS analysis, whereas the supernatants from urine extraction were further purified using polyamide (PA) SPE cartridges and then analyzed by UHPLC-MS/MS. Chromatographic separation was conducted on a Poroshell 120 HILIC-Z column (100 mm×2.1 mm, 2.7 μm) with a flow rate of 0.5 mL/min. The mobile phase was 0.1% (v/v) formic acid aqueous solution containing 5 mmoL/L ammonium formate and acetonitrile containing 0.1% (v/v) formic acid. The analytes were detected in the multiple reaction monitoring (MRM) mode after being ionized by an electrospray ion (ESI) in positive and negative modes. Quantitation of the target compounds was performed using the external standard method. Under the optimal conditions, the method showed good linearity in the range of 0.24-84.06 μg/L, with correlation coefficients greater than 0.995. The limits of quantification (LOQs) for the plasma and urine samples were 1.68-12.04 ng/mL and 4.80-34.4 ng/mL, respectively. The average recoveries for all the compounds were 70.4%-123.4% at spiked levels of 1, 2, and 10 times the LOQs, the intra-day precisions were 2.3%-19.1% and the inter-day precisions were 5.0%-16.0%. The established method was used to determine the target compounds in the plasma and urine from mice intraperitoneally injected with 14 shellfish toxins. All 14 toxins were detected in the 20 urine and 20 plasma samples, with contents of 19.40-55.60 μg/L and 8.75-13.86 μg/L, respectively. The method is simple, sensitive, and only requires a small amount of sample. Therefore, it is highly suitable for the rapid detection of paralytic shellfish toxins in plasma and urine.

HPLC-MS/MS determination and the postmortem distribution or postmortem redistribution of paraquat and its metabolites in four fatal intoxication cases

HPLC-MS/MS analysis and postmortem distribution or postmortem redistribution of paraquat and its two metabolites in poisoning death cases were reported. Paraquat, monoquat, and paraquat monopyridone were extracted from the sample with acetonitrile or methanol, respectively, detected by ZORBAX HILIC Plus (4.6 × 100 mm, 3.5 μm) chromatographic column, with 0.1 % formic acid aqueous solution - 0.1 % formic acid acetonitrile solution (v/v) as mobile phase. Paraquat, monoquat, and paraquat monopyridone had a good linear relationship within the range of 10–1000, 1–400, and 1–1000 ng/mL (or g), the correlation coefficient (r) were all ≥ 0.9996. Their detection limits were lower than 1 ng/mL (or g). The detection accuracy was 91.25∼113.44 %. The intra-day and inter-day precision were 1.51–3.99 % and 1.92–4.93 %, respectively. This method was used to detect and analyze four rare paraquat poisoning cases. The distribution of paraquat, monoquat, and paraquat monopyridone is uneven, which is relatively high in the heart, blood, lung, and kidney. Heart blood/Peripheral blood ratio of paraquat, monoquat, paraquat monopyridone concentration in two poisoned cases were 1.4, 2.0, 1.5 and 1.9, 1.3, 1.2, which showed a location dependent postmortem redistribution. This is the first time that HPLC-MS/MS and the postmortem distribution or postmortem redistribution of paraquat metabolites in poisoned death cases have been reported. This research provides scientific basis for forensic identification of paraquat poisoning cases and extraction of biological specimen.

Performance evaluation of HCOOH micro-fluidic fuel cell using Ni wire electrode

A membrane-free low cost microfluidic fuel cell (μFFC) consisting a trident shaped channel is molded into a poly(dimethyl siloxane) block and Ni wires affixed therein that doubled up as the catalyst and electrical connectors. Streams of aqueous acidic solutions of formic acid as the anolyte (fuel), KMnO4 as the catholyte (oxidant) and an acid electrolyte, flown through the respective channels at a constant rate ensured laminar flow across the length of the channels, while being in contact with the Ni wires, thereby tapping its’ catalytic activity for good electrochemical performance. The effect of varying fuel or oxidant concentration on the μFFC performance is studied. In the chronopotentiometric mode, the high catalytic activity of Ni allows high currents of the order of 1.25 mA to be sustained by the cell, particularly when the surface is fresh, and this current drops when the deposition of Mn, K, and S occurs. A flow rate of 150 μL/min. is found to be optimal, as the highest open-circuit voltage (OCV) of 1.33 V is attained at this flow rate. While the cell performance is largely unaffected by formic acid concentration, but it is controlled by KMnO4 concentration. Higher oxidant concentrations yielded higher OCVs, due to more amount of the five-electron reaction, occurring at the cathode enhancing the charge separation and hence the OCV. DRT studies of the EIS data resolved two different time constants for the anodic and cathodic processes. The μFFC delivers a maximum power density of 2.1 mW/cm2 and a stable current of 3.5 mA/cm2 for more than 10 min. at 0.6 V, thus validating its deployment in a variety of applications like diagnostic devices and as an independent power supply for MEMS devices.

Analysis on quality value transmitting of Qinggusan reference sample of classical prescription based on quantitative fingerprint technology

Qinggusan is the 69th prescription in the first batch of "Catalogue of Ancient Chinese Classic Formulas". In modern clinical practice， Qinggusan is mainly used to treat noninfectious fever. However， because few studies on Qinggusan reference samples and their quality value transfer are available， the development and promotion of its compound preparations are restricted. Therefore， establishing an accurate and comprehensive quality control method to clarify the critical quality attributes of Qinggusan reference samples is of great importance. In this study， 15 batches of Qinggusan reference samples were processed to determine the range of their dry extract ratios. Quantitative high-performance liquid chromatography （HPLC） fingerprint analysis was performed using a Waters Symmetry Shield RP18 column （250 mm×4.6 mm， 5 μm） with acetonitrile-0.1% （v/v） formic acid aqueous solution as the mobile phase in gradient elution mode. The flow rate was 1.0 mL/min， the column temperature was 30 ℃， and the detection wavelength was 254 nm. The HPLC fingerprints of the Qinggusan reference samples were established under these conditions to evaluate their similarity. The established method was systematically validated and found to demonstrate good precision， repeatability， and sample stability. Subsequently， characteristic peaks were identified and attributed by HPLC-quadrupole-time-of-flight-mass spectrometry （HPLC-Q-TOF-MS） analysis. MS was performed in electrospray ionization mode， the data were collected in both positive- and negative-ion modes， and the detection range was m/z 50-2000. The contents and transfer rate ranges of the index components， namely， gentiopicrin， mangiferin， picroside Ⅱ， picroside Ⅰ， and glycyrrhizic acid， were determined to analyze the quality value transfer of the samples. The results demonstrated that the dry extract rate of the 15 batches of Qinggusan reference samples ranged from 24.10% to 26.88% and that their fingerprint similarities were generally greater than 0.95. Twelve common peaks were identified by reference identification， literature comparison， and high-resolution MS analysis. Twelve compounds， including six iridoid glycosides， two flavonoids， one alkaloid， one triterpenoid saponin， and two others. Among them， L-picein， androsin， picroside Ⅳ， picroside Ⅱ and picroside Ⅰ were from Picrorhizae Rhizoma， loganin acid， swertiamarin and gentiopicrin were from Gentianae Macrophyllae Radix， neomangiferin and mangiferin were from Anemarrhenae Rhizoma， dichotomine B was from Stellariae Radix， and glycyrrhizic acid was from Glycyrrhizae Radix et Rhizoma. The five key components presented good linear relationships in their respective linear ranges， and all correlation coefficients were higher than 0.999. The relative standard deviations （RSDs） of precision， stability， and repeatability were less than 1.3%. The average recoveries varied between 95.92% and 102.5%， with RSDs less than 3.9%； these values meet the requirements defined in the 2020 edition of the Chinese Pharmacopoeia. The contents of gentiopicrin， mangiferin， picroside Ⅱ， picroside Ⅰ， and glycyrrhizic acid in the 15 batches of reference samples were in the range of 17.92-27.55， 1.83-4.42， 23.08-36.44， 8.43-15.04， and 0.94-2.39 mg/g， respectively， and their transfer rates from the decoction pieces to the reference samples were 47.91%-63.95%， 22.96%-59.39%， 60.82%-77.82%， 64.25%-99.53%， and 15.30%-39.30%， respectively. In this study， the chemical components of Qinggusan reference samples were comprehensively identified and their quality value transfer was studied through the combination of HPLC fingerprinting and MS. Clarification of the critical quality attributes of Qinggusan reference samples could provide a basis for the quality control of Qinggusan compound preparations.

Simultaneous Determination of Three Compounds in Rat Plasma by UHPLC-QQQ-MS/MS and Its Application to Pharmacokinetics of Banxia Baizhu Tianma Tang.

A rapid and highly selective and sensitive ultra-high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UHPLC-QQQ-MS/MS) method was applied to simultaneously determine ephedrine, gastrodin, and liquiritin in rat plasma. The three analytes and vitexin-2″-O-rhamnoside (I.S.) were analyzed on a Waters Acquity UPLC C18 column (1.7 μm, 2.1 mm × 100 mm) at 30°C with gradient mobile phase consisting of 0.1% formic acid aqueous solution (A) and acetonitrile (B) after one-step direct protein precipitation with acetonitrile. The detection was performed by multiple reaction monitoring (MRM) mode via electrospray ionization (ESI) source in positive and negative ion modes. The product ions m/z 166.1⟶148.1, 285.1⟶123.1, 417.1⟶255.1, and 579.0⟶433.1 were used for determination of ephedrine, gastrodin, liquiritin, and I.S., respectively. The calibration curves of the three analytes were linear with r 2 greater than 0.994. The intra and interday precision RSD% was less than 11.5 and 13.4. The intra and interday precision RE% was between -10.4% and 9.33%. The average extraction recoveries of the three analytes were no less than 86.88 ± 1.08%. The developed and validated method was for the first time applied to the pharmacokinetics of three compounds in rat plasma after intragastric administration of Banxia Baizhu Tianma Tang.

Comparative Investigation Between Raw and Stir-Frying Processed Cuscutae Semen Based on HPLC Fingerprints Coupled With Chemometric Methods.

The curative effect of Cuscutae Semen (CS) could be adjusted after stir-frying, and it is difficult to distinguish between the raw CS and stir-fried processed Cuscutae Semen (SFCS) in clinical practice. The paper aims to establish the fingerprints of raw and fried Cuscutae Semen products by high-performance liquid chromatography (HPLC) so that the compounds in raw and stir-fried products could be analyzed qualitatively and quantitatively. At the same time, the chemometrics method was used to evaluate the difference between CS and SFCS to provide reference for the research of traditional Chinese medicine (TCM) CS. The raw and SFCS products' related substances were separated on a C18 column (250 mm × 4.6 mm, 5 µm) maintained at 30 °C (column temperature). The mobile phase comprised 0.1% formic acid aqueous solution (A) and acetonitrile (B), and a detection wavelength of 328 nm. The data were imported into statistical software for chemometric analysis. The developed HPLC method exhibits good linearity and has good systematic applicability. The content of these 12 compounds in the samples was further determined and the data analyzed by chemometrics. The results showed that the composition of CS changed on heating, and HCA showed that CS and SFCS could be clearly distinguished. PCA showed that six components caused differences, namely neochlorogenic acid, cryptophyllogenic acid, caffeic acid, quercetin, isorhamnetin, and kaempferol. This study unequivocally establishes a chromatographic fingerprint method intended for the extensive analysis of raw and stir-fried processed CS, which could substantially enhance the quality control of CS and the rational development and utilization of TCM resources. This method for the simultaneous quantification of multiple compounds in CS and SFCS revealed the components responsible for the differences between raw and processed products. This will provide support for quality control of this herbal medicine.

Aluminum Anodizing in an Aqueous Solution of Formic Acid with Ammonium Heptamolybdate Additive

Morphology, composition, and fluorescence properties of anodic alumina/carbon composites formed in an aqueous solution of formic acid with ammonium heptamolybdate additive at 60–80 V were studied concerning the amount and state of carbon embedded in the alumina structure. According to scanning electron microscopy studies, the composites possess a hierarchical structure with multi-branched pores with a dense, cracked cover layer on the film surface. On the reverse side (i.e., anodizing front), hexagonal-shaped cells with an average diameter of about 180 nm were formed. Linear sweep voltammetry and study of current transient curves demonstrated that the anodizing process is non-steady, which led to the generation of non-uniform current pathways and resulted in the formation of the multi-brunched porous structure. Thermogravimetry/differential thermal analysis and infrared spectroscopy showed that the average carbon content is ca. 5.5 mass%, and the carbon embedded in the alumina is in the form of CO2, CO, carboxylate ions, and a-C:H. X-ray-induced Auger electron spectroscopy of the surface and reverse sides of the films proved that carbon is not only on the surface but also is homogeneously distributed through the oxide layer. According to fluorescence studies, alumina/carbon composites have a wide blue fluorescence in the wavelength range of 350–700 nm with a maximum at around 455 and 460 nm for surface and reverse sides, respectively. Our findings imply that the fluorescence spectrum dynamics is non-exponential and can be described as a superposition of several decay components. These can be different carbon-containing compounds and functional groups, such as OH, C=O, and COOH.

An analytical method for the determination of glyphosate and aminomethylphosphoric acid using an anionic polar pesticide column and the application in urine and serum from glyphosate poisoning patients.

An analytical method for the determination of glyphosate (GLY) and aminomethylphosphoric acid (AMPA) in biological fluid samples (serum and urine) from poisoning patients using liquid chromatography-tandem mass spectrometry (LC-MS/MS) is established. After the sample pretreatment, including protein precipitation and a modified liquid-liquid extraction method, the chromatographic separation was conducted on a trifunctional modified hydrophilic column. The mobile phases in the gradient program were 2.5% formic acid aqueous solution and acetonitrile. The multiple reaction monitoring (MRM) models and the isotope-labeled internal standards were used in the acquisition process. Good linearities and satisfying recovery rates were obtained in two sample matrices with good RSDs. The detection limits of GLY and AMPA were <2 μg L-1, which were close to those obtained in our previous research. The established method was applied to biological samples from five patients with glyphosate intoxication. The analysis of the trend for the concentration of GLY and AMPA in two biological samples was investigated, and the difference in the downward trend of AMPA in urine was found in patients with a relatively higher concentration of GLY in serum.

Comparison of the pharmacokinetics of timosaponin AIII, timosaponin BIII, and mangiferin extracted from crude and salt-processed Anemarrhenae Rhizoma by UPLC-MS/MS.

Processing is a traditional method for preparing decoctions of traditional Chinese medicine (TCM) that is imperative for reducing toxicity, increasing efficacy, and adjusting the properties of pharmacologically active components of the TCM. Salt processing of Anemarrhenae Rhizoma (AR), a traditional Chinese herb, has been employed since the Song dynasty and can enhance the ability of AR to enriching the Yin and downbearing fire according to the traditional theory recorded in the Enlightenment on Materia Medica. Previous research found that the hypoglycemic effect of AR was enhanced after salt processing, and the concentrations of three components, namely timosaponin AIII, timosaponin BIII, and mangiferin, all of which have hypoglycemic activities, have been found to be significantly increased after salt processing. In this study, we established an ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method to ultimately measure the concentrations of timosaponin AIII, timosaponin BIII, and mangiferin in rat plasma after administration of unprocessed AR and salt-processed AR (SAR) to the rats to further elucidate how salt processing affects the pharmacokinetic profiles of each of these compounds. Separation was achieved on an Acquity UPLC HSS T3 column. The 0.1% formic acid aqueous solution (v/v) and acetonitrile were used as the mobile phase system. Calibration curves of each compound in blank rat plasma, as well as the accuracy, precision, stability, and recovery of the total three analytes, were then measured to validate the method. The C max and AUC0-t values of timosaponin BIII and mangiferin in the SAR group were significantly higher than those of the AR group, while the T max values of timosaponin BIII and mangiferin in the SAR group were shorter than in the AR group. These results indicated that salt processing improved the absorption and bioavailability of timosaponin BIII and mangiferin in Anemarrhenae Rhizoma, and they provide a rationale for how the salt processing enhances the hypoglycemic effect of Anemarrhenae Rhizoma.

Analysis and Evaluation on the Quality of Pueraria Lobata in the Market Based on High Performance Liquid Chromatography (HPLC)

Objective: To evaluate the quality of Pueraria lobata sold in the market and establish a HPLC method for the analysis of Pueraria lobata. Method: Acclaim 120 C18 chromatographic column (5 μm. 4.6 * 250mm), acetonitrile-0.1% formic acid aqueous solution was used as the mobile phase for gradient elution, and the contents of 5 components, 3'-methoxy puerarin, puerarin, daidzin, daidzein, and 3'-hydroxypuerarin, were determined in 11 commercial pueraria lobata from different habitats. Results: The contents of these five components in pueraria lobata from different habitats were different. Anhui No. 003 and No. 006 have higher chemical constituents. Conclusion: The method established in this experiment is accurate, with good separation effect, and can be used to detect the content of five different substances in Pueraria lobata. The determination results can provide valuable reference information for the purchase of traditional Chinese medicine stores and provide effective scientific basis for the development of Pueraria lobata resources.

The experience in the development and validation of method for testosterone measurement in blood serum of premenopausal women using HPLC-MS/MS

Testosterone assessment is essential for detecting biochemical hyperandrogenism, one of the important diagnostic criteria of polycystic ovary syndrome (PCOS) both in clinical practice and in epidemiological studies. Currently, tandem liquid chromatography-mass spectrometry (LC-MS/MS) is the most preferred technique to measure testosterone level in women. Its validation is important to reproducibility of androgen tests results for clinical practice and for epidemiological studies of the prevalence PCOS.The aim of the study. To develop and validate a method for determining total testosterone in blood serum using highly efficient LC-MS/MS to assess androgenemia in the epidemiological study of the prevalence of PCOS and its phenotypes in Eastern Siberia (ESPEP STUDY).Materials and methods. We determined a total testosterone level in serum blood using triple quadrupole mass spectrometer LCMS-8060 (Shimadzu, Japan). The protocol of technique was developed using self-prepared purified human testosteronefree serum with a known concentration of analyzed compound. We used the serum samples of women of reproductive age to test the developed method.Results. Optimum chromatographic conditions were obtained with a Kromasil 100-2.5-C18 column (2.1 mm × 100 mm; AkzoNobel, Netherlands), and an isocratic elution mode using a mobile phase consisting of acetonitrile and 0.1 % aqueous solution of formic acid. The total flow rate was 0.35 ml/min. The lower limit of quantification was 5 ng/dl with an average accuracy of 100.2 %. During the approbation of the method in a test population sample of 1138 premenopausal women (mean age – 34.3 ± 6.3 years), the median testosterone concentration was 26.9 ng/dl.Conclusion. It was found that the proposed method for determining testosterone in blood serum has acceptable linearity and reproducibility and meets the requirements for bioanalytical methods under the regulatory documentation. This method can be used for clinical practice and epidemiological study of the prevalence of PCOS.

Analysis of Chemical Constituents of Traditional Chinese Medicine Jianqu before and after Fermentation Based on LC-MS/MS

To detect the chemical constituents in Jianqu samples under different fermentated states by using UPLC-QTOF-MS/MS technology, to conduct preliminary analyses, and to establish an HPLC method for the simultaneous determination of hesperidin and naringenin in Jianqu, and the variation of the two components during fermentation were compared. Waters ACQUITYTM UPLC HSST3 column (2.1 mm × 100 mm, 1.8 μm) was used; the mobile phase was 0.1% formic acid aqueous solution (A)-0.1% formic acid acetonitrile (B); The flow rate was 0.4 mL·min-1 with gradient elution; the column temperature was 45 °C; injection volume was 5 μL. The mass spectra of the samples were collected by negative ion mode under the electrospray ion source, and the data were screened and matched by UNIFI software. Hypersil gold C18 column (100 mm × 2.1 mm, 1.9 μm) was used; the mobile phase was acetonitrile (A)-0.1% acetic acid (B);; the flow rate with gradient elution was 0.3 mL·min-1; the column temperature was 30 °C; the injection volume was 2 μL. The content changes of hesperetin and naringenin in Jianqu at different fermentation time were detected. A total of 54 compounds were identified, including flavonoids, amino acids, organic acids, terpenoids, coumarins, lignans, and other compounds. Under the selected HPLC conditions, the linear relationship between hesperidin and naringenin was discovered (r2 = 0.9996). The content of hesperidin and naringenin changed significantly in the whole fermentation process. The highest concentration of content was observed at 36 h of fermentation and then decreased to varying degrees. This experiment can effectively identify various chemical components in Jianqu during different fermentation periods, and determine the content of the characteristic components, so as to provide a scientific basis for further study of Jianqu fermentation processing technology as well as a sound pharmacodynamic material basis.

Pharmacokinetic study of the main components of Tanreqing capsules and Tanreqing injections in beagles by liquid chromatography–tandem mass spectrometry

BackgroundTanreqing capsules (TRQCs) and Tanreqing injections (TRQIs) are widely used in the treatment of respiratory diseases. In this study, a simple, rapid, and sensitive liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed for simultaneous quantification of the main components of Tanreqing, which include chlorogenic acid, ursodeoxycholic acid, chenodeoxycholic acid, and baicalin, in beagle dog plasma to compare their pharmacokinetic parameters.MethodsPlasma samples were pretreated with protein precipitation. Chromatographic separation was performed on Waters Acquity UPLC HSS T3 (2.1 mm × 100 mm, 1.8 μm) column using a gradient elution with (A) 0.1% (v/v) formic acid aqueous solution and (B) acetonitrile. Six healthy beagles were divided into two groups, and a crossover, comparative pharmacokinetic study of TRQC (0.09 g/kg) and TRQI (0.5 mL/kg) after a single-dose administration or daily doses over 7 days was carried out. One group was administrated a single dose of TRQC and followed continuously for 7 days, whereas the other group was treated with TRQI in the same way.ResultsThe calibration curves were linear over the ranges of 2.00–1000.00 ng/mL for baicalin, 10.00–5000.00 ng/mL for ursodeoxycholic acid, 1.00–500.00 ng/mLfor chenodeoxycholic acid and chlorogenic acid, respectively. The relative standard deviation of both intra-day and inter-day accuracy is less than 11.23%. The average extraction recovery of all compounds was greater than 82.21%. The major pharmacokinetic parameters of the four compounds were not significantly different between the two formulations (P > 0.05).ConclusionsThe measured levels of the four major components of TRQCs and TRQIs were comparable in these dogs, providing a reference for the clinical application of TRQCs instead of TRQIs.

Quality evaluation of Fufang Jinqiancao granules based on ultra performance liquid chromatography-ultraviolet detection quantitative fingerprint combined with chemical pattern recognition

Fufang Jinqiancao granules have a large market demand due to the fact that they contain diuretics, inhibit urinary calculi formation, and exhibit both anti-inflammatory and antioxidant effects. In the current study, a fast and efficient quantitative ultra performance liquid chromatography-ultraviolet detection (UPLC-UV) fingerprinting method was established to analyze the Fufang Jinqiancao granules, while a chemical pattern recognition technology was used to evaluate the quality of the granules over different years. More specifically, the UPLC-UV system consisted of a Waters Acquity UPLC BEH C18 column (100 mm×2.1 mm, 1.7 μm), acetonitrile (mobile phase A), and a 0.1% formic acid aqueous solution (mobile phase B), wherein a gradient elution protocol was followed. Ultra performance liquid chromatography-quadrupole-time of flight-mass spectrometry (UPLC-Q-TOF-MS, Agilent Infinity Ⅱ 1290-6545) was used in combination with reference substances and literature comparisons to identify the common peaks present in the quantitative fingerprint. The fingerprints of 35 batches of Fufang Jinqiancao granules were established by means of the quantitative UPLC-UV fingerprinting method, and the fingerprint data obtained for these samples were further analyzed by chemical pattern recognition techniques, including hierarchical cluster analysis (HCA) and principal component analysis (PCA). The quality difference markers, namely mangiferin and isomangiferin, were screened, and their contents were determined. It was found that 12 common peaks existed in the fingerprint of the Fufang Jinqiancao granules, and the similarities of all 35 batches of samples were greater than 0.952. In addition, for the purpose of HCA, the 35 batches were divided into two categories, of which sample years 2018 and 2019 belonged to one category, and sample years 2020 and 2021 belonged to another category. Notably, PCA gave the same clustering trends as HCA. Based on the obtained results, the mangiferin and isomangiferin components responsible for the differences between the 2018, 2019 and 2020, 2021 samples were further screened by orthogonal partial least squares discriminant analysis (OPLS-DA). Moreover, the contents of the 35 batches of samples were determined using the two differential markers mangiferin and isomangiferin as indicators. The obtained results indicated that the chromatographic peaks of all 35 batches had acceptable resolutions, with mangiferin exhibiting a good linear relationship in the range of 5.3291-133.2276 mg/L, and isomangiferin exhibiting a similar linear relationship in the range of 4.1847-104.6170 mg/L. The average recovery of mangiferin was 101.7%-105.6%, with a relative standard deviation (RSD) of 0.63%-1.43%, while that of isomangiferin was 103.4%-105.5%, with an RSD of 0.60%-1.18%. Importantly, all RSD values were less than 1.43%, thereby indicating that our method meets the requirements of the Chinese Pharmacopoeia (2020 Edition). Among the 35 batches of samples, the contents of mangiferin and isomangiferin were higher in the 2020 and 2021 samples, and the content fluctuation range was smaller. Overall, the development of an accurate and reliable quality control method for Fufang Jinqiancao granules, and a reasonable and effective quality evaluation of Fufang Jinqiancao granule samples from different years was realized. We therefore expect that this study will provide a reference for establishing a more systematic and comprehensive quality control system.