Formic Acid Aqueous Solution Research Articles

Detection of sivelestat and its metabolite in small volumes of plasma from Chinese ALI/ARDS patients with SIRS via high-throughput UPLC-MS/MS: A pharmacokinetic study

In this study, we developed a sensitive and efficient analytical approach combining a 96-well plate-based protein precipitation strategy with ultra-performance liquid chromatography electrospray ionization tandem mass spectrometry (UPLC-MS/MS) in order to assess the pharmacokinetic (PK) properties of sivelestat and its metabolite XW-IMP-A in samples of plasma from ALI/ARDS patients with SIRS. The samples were separated via gradient elution with a C18 column (Phenomenex Kinetex, C18, 2.6 μm, 100 Å, 50 × 2.1 mm) using 0.1 % formic acid aqueous solution (A) and acetonitrile-methanol (1:1, V:V) (B) as a mobile phase at a 0.6 mL/min flow rate. UPLC-MS/MS spectra were generated in positive ion mode, and multiple reaction monitoring (MRM) was used to detect the following transitions: m/z 435.1 → 360.0 for sivelestat, m/z 469.0 → 394.0 for sivelestat-IS, m/z 351.0 → 276.0 for XW-IMP-A, and m/z 384.9 → 310.0 for XW-IMP-A-IS. This assay was run for 2.5 min in total, and achieved lowest limit of quantitation values of 2.0 ng/mL and 0.5 ng/mL for sivelestat and XW-IMP-A, respectively, while remaining highly linear from 2−500 ng/mL for sivelestat (r2 ≥ 0.9900) and from 0.5−125 ng/mL for XW-IMP-A (r2 ≥ 0.9900). These validated data were consistent with US Food and Drug Administration (FDA) and European Medicines Agency (EMA) acceptance criteria. In addition, this method was successfully applied to the steady-state PK evaluation of ALI/ARDS patients with SIRS.

Fast high-performance liquid chromatography quantification of ten phenolic acids in honey using chemometric second-order calibration method

This study aims at the determination of ten phenolic acids in honey using high-performance liquid chromatography-diode array detection (HPLC-DAD) combined with a chemometric second-order calibration method. First, the accuracy of the model was investigated by analysis of the calibration samples and validation samples. Satisfactory results were obtained; the ten phenolic acids exhibited good linearity, and the correlation coefficient (R) was in the range 0.9982-0.9999, with average recoveries of 97.6% to 101.1%, which proved that the model was stable and reliable. Second, the types and operating conditions of the SPE columns were determined by experiments using simulated honey; HLB column was selected, washed with 0.1%(v/v) formic acid aqueous solution, and eluted with methanol. Finally, the phenolic acid contents in jujube flower honey were determined under the optimum conditions for simulated honey. The recoveries of the analytes were 62.1%-93.8%, which met the requirements considering the variety of target analytes and the complexity of the honey substrate. In addition, the efficiency of the method was validated by figures of merit and statistical parameters, including sensitivity (SEN), selectivity (SEL), root-mean-square error of prediction (RMSEP), limit of detection (LOD), and limit of quantification (LOQ); the obtained results were satisfactory. This method is simple, fast, and accurate, and it can be used for the quantitative analysis of the target analytes in complex substrates.

Determination of diazepam in aquatic products by ultra performance liquid chromatography-tandem mass spectrometry with pass-through solid phase extraction

A method was developed for the determination of diazepam in aquatic products by pass-through solid phase extraction-ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The analyte was extracted with acetonitrile directly and purified on a Prime HLB solid phase extraction column (60 mg/3 mL). The separation was performed on an Acquity UPLC BEH C18 column (100 mm×2.1 mm, 1.7 μm)using methanol-0.1% (v/v) formic acid aqueous solution as the mobile phase in gradient elution mode. Qualitative analysis was performed in the multiple reaction monitoring (MRM) mode. The analyte was quantified by matrix-matched external standard curves. The results showed good linear relationship in the range of 0.1-10 ng/mL, and the correlation coefficient (r2) was greater than 0.99. The spiked recoveries of diazepam were 88.2%-101.1% at the spiked levels of 1.5, 3.0 and 15.0 μg/kg, and both the intra-and inter-day precisions were less than 10%. The developed method is simple, rapid and accurate, and it can meet the requirements for diazepam determination in aquatic product samples.

Determination of four antipyretic and analgesic drugs in water by solid-phase extraction coupled ultra-performance liquid chromatography-tandem mass spectrometry

The widespread use of pharmaceutical and personal care products (PPCPs), including antipyretic and analgesic drugs, in the last two decades had led to the existence of PPCP residues in the environment, thus raising concerns about their pseudo-persistent nature and potential threat to human health. Generally, most of the detected contaminants are present at low levels (ranging from ng/L to μg/L) in environmental water. Therefore, advanced analytical methodologies are crucial to monitor the occurrence and distribution of antipyretic and analgesic drugs in environmental water. However, trace analysis of environmental pollutants is always challenging because it is necessary to extract analytes present in the sample at ultralow levels from complex environmental matrices. Therefore, an appropriate sample pretreatment is necessary to enrich the target compounds. Conventional solid-phase extraction materials show poor efficiency for the enrichment of antipyretic and analgesic drugs. We herein report a hydrophilic and lipophilic amphiphilic porous polymeric material GCHM (Guochuang hydrophilic material). GCHM was successfully prepared by a stepwise emulsification and micellization process using N-vinyl-2-pyrrolidone (NVP) and divinylbenzene (DVB) as raw materials. An ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed for the determination of four antipyretic and analgesic drugs in water using our solid-phase extraction (SPE) column. The water samples were extracted and purified by the GCHM solid-phase extraction column, and then analyzed by UPLC-MS/MS. Gradient elution was carried out with 0.1% formic acid aqueous solution and acetonitrile as the mobile phase. The target analytes were separated on an ACQUITY UPLC HSS T3 column (100 mm×2.1 mm, 1.8 μm), and multiple reaction monitoring (MRM) was conducted in the positive electrospray ionization mode. The isotope internal standard method was used for quantitative correction. Comparison of the enrichment efficiencies of Oasis HLB, Bond Elut Plexa, and GCHM revealed that GCHM showed the best performance. Different pH values affecting the enrichment efficiency of the GCHM SPE column were optimized, and the matrix effect was evaluated. The results showed that the four target analytes gave the best enrichment effect on the SPE column at pH 7, and the matrix effect for each substance was between 82.8% and 102.2%, indicating obvious matrix removal after the water sample was purified by the GCHM SPE column. Good correlation coefficients (r) greater than 0.995 were observed for all the target compounds in the range of 1-100 μg/L. The method limits of quantitation (S/N=10) ranged from 1 ng/L to 5 ng/L. The corrected recoveries were 85.6% to 106.4%, and the relative standard deviations (RSD) were under 5.6%. The GCHM solid-phase extraction column is inexpensive and efficient, being suitable for the detection of the four antipyretic and analgesic drugs in water. Subsequently, the occurrence of these selected antipyretic and analgesic drugs in water samples from Shanghai, Jiangsu, and Guangdong provinces were studied. The GCHM column has potential advantages over the commercial imported SPE column and is worthy of widespread application. This column can also aid the enrichment and purification of other compounds with similar structures or properties in water.

Determination of streptomycin and dihydrostreptomycin in grapes by liquid chromatography-tandem mass spectrometry

Streptomycin (STR) and dihydrostreptomycin (DSTR) are two of the most common aminoglycoside antibiotics used in veterinary medicine. STR is produced by some streptomyces griseus strains, and DSTR is a derivative of STR. In recent years, STR has been widely used in grapes to induce denuclearization. However, high levels of STR may have adverse effects like serious ototoxicity and nephrotoxicity. Therefore, to ensure the quality of grapes and the health of consumers, the regulation of STR and DSTR levels in grapes is required. An analytical method was developed for the identification and quantification of STR and DSTR in grapes by liquid chromatography-tandem mass spectrometry (LC-MS/MS). STR and DSTR are highly polar compounds due to the presence of various amino and hydroxyl groups in their structure. The determination of STR and DSTR poses a considerable analytical challenge, both during sample preparation and instrument analysis. In this study, the main factors governing the response, recovery, and sensitivity of these compounds, such as the type of chromatographic column, the type and proportion of the mobile phase and extraction solvent, the dosage of sodium 1-hexane sulfonate solution, and elution solvent and its volume, were investigated during sample pretreatment and instrument analysis. The STR and DSTR residues in the grape sample were extracted by ultrasonication with a phosphoric acid solution (pH 2), and cleanup and enrichment was performed using an Oasis HLB solid phase column. The analysis was performed using a UPLC Waters HSS T3 column (100 mm×2.1 mm, 1.8 μm) at the column temperature of 35℃. The injection volume was 2 μL. The mobile phase consisted of 0.1% formic acid aqueous solution and methanol with a volume ratio of 60:40. ESI-MS/MS was operated in multiple reaction monitoring (MRM) mode. External standard calibration curves were used for quantification. Based on the optimized method, both analytes displayed good linearity between 2 and 400 μg/L. The correlation coefficients were 0.9991-0.9997. Recoveries in spiked blank grape samples (5, 10, 20, and 40 μg/kg) ranged from 76.8% to 91.9%, with the relative standard deviations (RSDs) less than 10.2%, in compliance with the current legislation. The limits of detection and the limits of quantification of both analytes were 1 μg/L and 5 μg/kg, respectively. To assess the feasibility and potential of the proposed approach for routine analyses of STR and DSTR in other kinds of grape samples, the developed method was applied to the analysis of these compounds in red grapes, xinyu grapes, and xiahei grapes. The recoveries of STR and DSTR in the three kinds of blank grape samples were 77.2%-83.9% and 70.8%-78.9%, respectively, and the RSDs ranged from 3.0% to 15.6%. The results showed that the optimized methods can yield satisfactory recoveries for the analytes in grapes. In this method, the combination of Waters HSS T3 column to overcome the difficulties of the retention and separation of these highly polar compounds in the reverse phase, avoids the use of an ion-pair additive in the mobile phase to increase their retention, which is known to cause severe contamination of the column and serious ion suppression with electrospray ionization detection. In addition, the ideal enrichment and purification effect can be achieved by adding a sodium 1-hexane sulfonate solution to the superstratum extract with the use of only Oasis HLB for sample treatment. The method described herein has the advantages of easy operation, accuracy, and selectivity, making it feasible for the identification and quantification of STR and DSTR residues in grapes.

Challenges and stepwise fit-for-purpose optimization for bioanalyses of remdesivir metabolites nucleotide monophosphate and triphosphate in mouse tissues using LC–MS/MS

Remdesivir is a prodrug of the nucleotide analogue and used for COVID-19 treatment. However, the bioanalysis of the active metabolites remdesivir nucleotide triphosphate (RTP) and its precursor remdesivir nucleotide monophosphate (RMP) is very challenging. Herein, we established a novel method to separate RTP and RMP on a BioBasic AX column and quantified them by high-performance liquid chromatography-tandem mass spectrometry in positive electrospray ionization mode. Stepwise, we optimized chromatographic retention on an anion exchange column, improved stability in matrix through the addition of 5,5′-dithiobis-(2nitrobenzoic acid) and PhosSTOP EASYpack, and increased recovery by dissociation of tight protein binding with 2 % formic acid aqueous solution. The method allowed lower limit of quantification of 20 nM for RMP and 10 nM for RTP. Method validation demonstrated acceptable accuracy (93.6%–103% for RMP, 94.5%–107% for RTP) and precision (RSD < 11.9 % for RMP, RSD < 11.4 % for RTP), suggesting that it was sensitive and robust for simultaneous quantification of RMP and RTP. The method was successfully applied to analyze RMP and RTP in mouse tissues. In general, the developed method is suitable to monitor RMP and RTP, and provides a useful approach for exploring more detailed effects of remdesivir in treating diseases.

Selective, rapid and simultaneous determination of ergosterol and ergocalciferol in mushrooms by UPLC-Q-TOF-MS

An ultra-performance liquid chromatography coupled to atmospheric pressure chemical ionization-quadrupole time-of-flight mass spectrometry method has been optimized and validated for the determination of ergosterol and ergocalciferol in mushroom samples, using cholecalciferol as surrogate standard.The separation was carried out with a Synergi Hydro-RP column (100 mm x 3.00 mm i.d, 2.5 μm particle size), (Phenomenex, CA, USA) column, thermostated at 35 °C. The mobile phase was 0.1 % formic acid aqueous solution and methanol in gradient elution mode and it was achieved in 5 min approximately. Detection was achieved by atmospheric pressure chemical ionization in positive mode and quadrupole time-of-flight mass spectrometry. Desolvation and interface temperatures were set at 500 °C and 150 °C, respectively. The recoveries obtained were within 92–105 % for ergosterol, 77–81 % for ergocalciferol and 83–87 % for cholecalciferol. Method limits of detection were 0.4 and 0.5 μg g−1 for ergosterol and ergocalciferol, respectively, and method limits of quantitation were 1.2 and 1.3 μg g−1 for ergosterol and ergocalciferol, respectively.A rapid and simple extraction procedure using small amount of sample (100 mg) with hexane was optimized and the method was applied to the determination of ergosterol and ergocalciferol in white button mushrooms (Agaricus bisporus var. bisporus) exposed to UV irradiation. Results were compared to the corresponding non-irradiated mushrooms.

Kinetics of Carbon Dioxide Release During the Ozonation of Aqueous Solutions of Formic Acid

The kinetics of carbon dioxide release during the interaction between ozone and an aqueous solution of formic acid in a bubble column reactor has been studied for the first time. A simple and effective method of determining carbon dioxide in a gas stream has been developed. It is shown that the formation of 1 mol of CO2 corresponds to the consumption of ~2.4 mol of O3. The value of the true rate constant of the reaction between O3 molecule and formate ion HCOO− has been found (120 ± 15 L mol−1 s−1 at 20–21°C). It has been confirmed that O3 does not interact with undissociated HCOOH molecules.

Determination and pharmacokinetics of calycanthine in rat plasma by UPLC-MS/MS

AbstractCalycanthine is an important class of alkaloids extracted and isolated from the roots, leaves, flowers and fruits of Chimonanthus praecox. In this work, the UPLC-MS/MS method was used for determination of calycanthine in rat plasma, and the pharmacokinetics in rats were investigated. Midazolam was used as an internal standard (IS), and methanol precipitation method was used to pretreatment the rat plasma samples. Chromatographic separation was achieved on a UPLC BEH C18 (50 × 2.1 mm, 1.7 μm) column with the mobile phase of methanol- 0.1% formic acid aqueous solution with gradient elution. Multiple reaction monitoring (MRM) mode with positive ionization was applied for quantitative analysis, m/z 347.3 → 246.7 and 326.2 → 291.4 for calycanthine and IS, respectively. The results indicated that within the range of 1–200 ng/mL, linearity of calycanthine in rat plasma was good (r &gt; 0.995), and the lower limit of quantification (LLOQ) was 1 ng/mL. Accuracy range was between 90.6 and 109.4%, precision (RSD) of calycanthine was less than 14%. The matrix effect was between 97.9% and 105.4%, the recovery was better than 85.6%. The developed UPLC-MS/MS method was successfully applied in the pharmacokinetics of calycanthine in rats after oral and intravenous administration. The absolute bioavailability of the calycanthine was 37.5% in rats.

Autocatalytic reaction mechanism of nitric acid and formic acid mixtures based on thermal and in situ Raman spectroscopic analyses

The oxidation of organic compounds with nitric acid has the potential to undergo a runaway hazardous reaction and explosion after the thermal–neutral induction period. The purpose of this study is to obtain a better understanding of the oxidation reaction mechanism to clarify the specific conditions under which the exothermic reaction occurs. In this study, the oxidation reactions of formic acid with nitric acid were investigated to represent a typical mixture of organic compound and nitric acid. From the results of thermal analysis, the overall reaction rate in a 15% nitric acid and 10% formic acid aqueous solution was formulated using an autocatalytic reaction model. The apparent activation energy was 75.2 kJ mol−1, and the pre-exponential factor was 7.87 × 108 s−1. The reaction rate increased with either nitric or formic acid concentrations, emphasizing that it is important to treat the mixture at lower concentrations for thermal safety. As a result of the thermal and in situ Raman spectroscopic analyses, it was found that the concentration of nitrous acid increased with the progress of the reaction as nitric acid and formic acid changed into NO2, N2O4, HCO(O)NO, HCO(O)NO2, and so on. The reaction mechanism started from nitrous acid and the oxidation of formic acid with nitric acid is an autocatalytic reaction involving this nitrous acid-initiated cycle.

Mechanism of the Azeotropy Phenomenon in Aqueous Formic Acid Solutions

The mechanism of the azeotropy phenomenon has been established at a molecular level for the first time on the example of the HCOOH–H2O system, which has an azeotropic region. The studies are based on the regularities of the formation of heteroassociates with strong hydrogen bonds in binary systems and on the assumption that both phases of a boiling azeotropic mixture are composed of the same heteroassociates. It has been established that an aqueous formic acid solution is azeotropic if the heteroassociates composing this solution at room temperature are converted under heating into the most stable of possible heteroassociates 2НСООН ∙ 2Н2О and 2НСООН ∙ Н2О, which are retained at boiling temperature. Such restructuring in the solution leads to the maximum strengthening of intermolecular interactions and occurs with minimum energy expenditures.

A Reliable LC-MS/MS Method for the Quantification of Two Pairs of Isomeric Flavonoids from Commelina Communis Linn in Rat Plasma: Validation and Pharmacokinetic Applications

Background: Commelina communis Linn (Commelinae Herba) is a traditional Chinese medicine that can be used both as food and as medicine. It has been used to treat a variety of disorders, including a cold, high fever, sore throat, edema and oliguria for many years. Two pairs of isomeric flavonoid glycosides are the main active components in Commelina communis Linn, and they have a high content. Objective: The objective of this study was to determine the pharmacodynamic and pharmacological effects of Commelina communis Linn. Method: A sensitive, efficient, and rapid LC-MS/MS method was developed to simultaneously identify two pairs of isomeric flavonoid glycosides in rats. Chromatographic separation was carried out on a Wonda Cract ODS-2 C18 column (150 mm x 4.6 mm, 5 μm) using a mobile phase composed of 0.1% formic acid (aqueous solution) and methanol at a flow rate of 0.8 mL/min. The detection of the four analytes and the internal standard (IS) sulfamethoxazole was performed with multiple reaction monitoring (MRM) in negative electrospray ionization mode. All the analytes were eluted within 20 min. Results: This method was successfully applied for simultaneous identification of the concentrations of the four compounds in the plasma after the oral administration of 10 mL/kg Commelina communis Linn extract to rats. The pharmacokinetic study indicated that analytes reached their Cmax in approximately 15 min and could be detected until 12 h. Conclusion: The method complies with the State Food and Drug Administration guidelines for selectivity, sensitivity, accuracy, precision, matrix effect, extraction recovery and stability. This is the first report on the pharmacokinetics of Commelina communis Linn. The information gained from this research may be valuable for the preclinical and clinical applications of Commelina communis Linn.

Simultaneous quantification and pharmacokinetic evaluation of roflumilast and its N-oxide in cynomolgus monkey plasma by LC-MS/MS method.

Roflumilast (ROF), a nonsteroidal anti-inflammatory drug, has successfully been used to treat systemic and pulmonary inflammation associated with chronic obstructive pulmonary disease. To evaluate its pharmacokinetics in monkeys, a sensitive, rapid and reliable liquid chromatography with tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of ROF and its N-oxide metabolite (RNO). The mobile phase contained 0.1% formic acid aqueous solution (A) and 0.1% formic acid acetonitrile solution (B). All monkey plasma samples were pretreated using protein precipitation with methanol-acetonitrile (50:50, v/v) in 50 μl plasma samples. Chromatographic separation was performed with mass spectral acquisition performed in positive electrospray ionization, utilizing multiple reaction monitoring. This method was successfully applied to a pharmacokinetic study in cynomolgus monkeys. Following administration of a single oral dose of 1 mg/kg ROF in monkeys, pharmacokinetic data for ROF and RNO was reported for the first time. After oral administration, ROF was rapidly absorbed and metabolized to its metabolite RNO. The mean area under the curve value of RNO was ~13 times larger than that of ROF, suggesting that most ROF was metabolized to RNO in cynomolgus monkeys.

A density functional theory study on the structure formation of Al(III) carboxylate complexes in aqueous aluminum sols

AbstractIn‐depth studies of the structure of precursor sols is very important for understanding the subsequent sol to gel transition. Here, density functional theory was applied to study the reaction of Al powder with formic and acetic acid in aqueous solution to find the structure of Al(III) complex in precursor sols. The Al3+ ion obtained by dissolving Al powder in aqueous solution of formic and acetic acid would preferentially coordinate with water molecules to form aluminum hydrates. As the reaction energy barrier of aluminum hydrates with CH3COO− and HCOO− was comparable, both aluminum formoacetate and other aluminum carboxylate monomers could be obtained. Most Al(III) complexes formed by other carboxylate monomers were similar to that prepared from aluminum formoacetate. However, some Al(III) monomers and Al(III) dimer with different structural characteristics might be detrimental to the formation of linear polymers. The formation of other aluminum carboxylate monomers had great influence on the structure of precursor sols.

Pharmacokinetic Study of Thirteen Ingredients after the Oral Administration of Flos Chrysanthemi Extract in Rats by UPLC-MS/MS.

A rapid and reliable UPLC-MS/MS method was developed and validated for the simultaneous quantification of thirteen bioactive compounds (luteolin, cynaroside, luteolin 7-O-glucuronide, isochlorogenic acid C, chlorogenic acid, cryptochlorogenic acid, apigenin, apigenin 7-glucoside, acacetin, hyperoside, isoquercitrin, tilianin, and hesperidin) in rat plasma. The compounds were separated on an ACQUITY UPLC BEH C18 column (2.1 × 100 mm, 1.7 μm) with a gradient mobile phase system of acetonitrile and 0.1% (v/v) formic acid aqueous solution at a flow rate of 0.3 mL/min. All compounds were quantitated using Agilent Jet Stream electrospray ionization (AJS ESI) in a negative ion mode. The lower limit of quantification (LLOQ) for all compounds was below 5 ng/mL. The intra- and interday accuracy ranged from -13.0% to 14.0%, and precisions were less than 12.2%. The extraction recoveries of the compounds were in the range of 56.9% to 95.0%, and the matrix effect ranged between 71.6% and 109.3%. Stability studies proved that the thirteen compounds were stable under tested conditions, with a relative standard deviation (RSD) of less than 11.4%. This developed method was successfully applied to the pharmacokinetic study of the 13 bioactive compounds after oral administration of Flos Chrysanthemi extract in rat by UPLC-MS/MS. Pharmacokinetic parameters of 8 out of the 13 compounds investigated are presented in this paper.

A LC-MS/MS method for determination of 73 synthetic cathinones and related metabolites in urine

Synthetic cathinones, which are a group of β-keto analogs of phenethylamine, have been reported as the most emerging new psychoactive substances in the past decade. The quantity and variety of synthetic cathinones have continued to increase, which poses considerable risks to public health and social security. In this study, an analytical method based on liquid chromatography-tandem mass spectrometry (LCMS/MS) was established for the simultaneous determination of 73 synthetic cathinones and related metabolites in urine. The chromatographic analysis was performed using a Kinetex® Biphenyl column (10 cm ×2.1 mm, 1.7 μm), applying a gradient mobile phase, comprising 0.1 % formic acid aqueous solution with 5 mM ammonium acetate and 0.1 % formic acid methanolic solution; the entire run time of the analysis was within 8 min. The multiple reaction monitoring (MRM) mode was employed to collect the monitoring and quantitative ion pairs. Intra-day/inter-day precision and accuracy were less than 10 % for all the studied analytes. The limits of detection and quantification for all the analytes were 0.1–0.5 ng/mL and 0.5–1.0 ng/mL, respectively. The matrix effect was satisfactory for all the analytes, with a deviation lower than 20 %. The present method was further applied to 67 authentic urine samples in which 13 different synthetic cathinones were detected from 32 positive samples. The abuse of poly-synthetic cathinones was examined that up to seven items was detected in one case from authentic samples in this study.

Analysis of nine antioxidants in vegetable oils by high performance liquid chromatography

A method was developed for the determination of nine antioxidants in vegetable oils by high performance liquid chromatography (HPLC). The samples were extracted with methanol, and the fat in the samples was degreased by freezing. Separation of the targeted compounds was performed on an XBridge C18 column in gradient elution mode using methanol-0.1% (v/v) formic acid aqueous solution as the mobile phase. The analytes were detected using a diode-array detector by the external standard method. The stability and storage conditions for the nine antioxidants were systematically investigated. Ascorbyl palmitate (AP) was introduced into the preparation and pre-treatment of the targets. The concentration of AP was optimized to improve the stability and recovery of the targets. The effects of different extraction solvents and purification methods on the extraction efficiencies were discussed. The results showed that the nine antioxidants could be separated well under the optimized conditions. Good linear relationships in the linear range were obtained, and the correlation coefficients (R2) were greater than 0.999. The average recoveries of the nine antioxidants ranged from 85.3% to 104.1%, with RSDs of the method ≤5.0%. The limits of quantitation (LOQs) for the nine synthetic antioxidants were in the range of 0.6-3.0 mg/kg. The method is simple, rapid, sensitive, and it shows good recovery and reproducibility.

Rapid screening of illegally added poppy husk in hot pot sauce and soup by thermal desorption electrospray ionization-triple quadruple mass spectrometry

A thermal desorption electrospray ionization-triple quadruple mass spectrometry (TD-ESI-MS/MS) method was developed for the rapid screening of poppy husk in hot pot sauce and soup. The solid surface or liquid sample was directly touched by a simple metal probe. The analytes collected on the probe were desorbed and ionized using a TD-ESI source, after which the analyte ions were detected by MS/MS in multiple reaction monitoring (MRM) mode. The results were compared with those of colloidal gold card rapid detection and verified by high performance liquid chromatography coupled with triple quadrupole mass spectrometry (HPLC-MS/MS). The instrument gave the best response with the highest sensitivity under the following conditions: thermal desorption temperature, 260 ℃; injection solvent, 0.1% formic acid aqueous solution containing 10 mmol/L formic ammonium-acetonitrile (1:1, v/v); flow rate, 200 μL/h. The limits of detection (LODs) for papaverine, noscapine, and thebaine in five alkaloids were 2 μg/kg, while those for codeine and morphine were 10 μg/kg in hot pot sauce and 5 μg/kg in soup. The sensitivity of this method was significantly superior to that of the colloidal gold card rapid detection. The method was applied to 50 batches of hot pot sauce and soup. Noscapine, papaverine, thebaine, and morphine were detected in a positive sample of chicken soup, which was consistent with the result of the HPLC-MS/MS method. This method without sample preparation and chromatographic separation is fast, green, and environmentally benign, thus being suitable for the rapid qualitative analysis of poppy husk in food.

A Validated UPLC-PDA Method for Simultaneous Determination of 3 Biologically Active Isoflavans in Trigonella stellata Extract

In this study, an ultra-performance liquid chromatography (UPLC)/photodiode array method was developed for the simultaneous determination of trigonellan glucoside (1), isotrigonellan (2), and methoxy-isotrigonellan (3) in Trigonella stellata extract using an external standard method. The extract was prepared using a standardized method by maceration of the dried plant material in ethanol. The 3 isoflavans (1-3) were separated on an Acquity UPLC C18 column using gradient elution with a mobile phase consisting of 0.1% (v/v) formic acid aqueous solution and 0.1% (v/v) formic acid in acetonitrile, and ultraviolet detection. The method provides a linear correlation for all analytes over the investigated ranges with all correlation coefficients greater than 0.998. The validated lower limits of quantitation were 53, 127, and 5 μg/mL for isoflavans 1, 2, and 3, respectively. Intraday and interday precisions (percent relative SD [RSD%]) were less than 8.3% and accuracy (RE%) ranged from 90% to 100%. The method’s capability to remain unaffected by small, but deliberate variations in method parameters (method’s reliability during normal usage) described by the robustness showed RSD% less than 4.6% measured by varying 3 different parameters. The validated method was successfully applied to simultaneously determine the concentration of the 3 new isoflavans having anti-inflammatory and antidiabetic activities. The results revealed that the validated method can be used for quality control of herbal preparations containing these or similar isoflavans that are marketed for the prevention of inflammation and as antidiabetics.

Determination of 15 lipid regulators in fish meat by QuEChERS-ultra performance liquid chromatography-quadrupole/ electrostatic field orbitrap mass spectrometry

An analytical method was established for the determination of 15 lipid regulators in fish meat by QuEChERS combined with ultra performance liquid chromatography-quadrupole/electrostatic field orbitrap mass spectrometry (UPLC-Q/Orbitrap-MS). The samples were purified by optimized QuEChERS methods. The amounts of the adsorbent materials (primary secondary amine (PSA) (20, 60, 100, 140 and 180 mg), C18 (40, 100, 160, 220 and 280 mg) and sodium acetate (0.2, 0.6, 1.0, 1.4 and 1.8 g)) were optimized by the response surface method to obtain the best purification effect. The target compounds were separated on an XBridge-C18 column (100 mm×2.1 mm, 3.5 μm) using acetonitrile-0.1% (v/v) formic acid aqueous solution (containing 1.5 mmol/L ammonium acetate) as the mobile phases by a gradient elution program. Qualitative and quantitative analysis of the target compounds were performed in the full scan and secondary mass spectrometry scan (dd-MS2) modes with positive and negative ionization. The target compounds showed good linear relationships in their respective ranges, with correlation coefficients (R2) greater than 0.99. The limits of detection (LOD, S/N=3) and limits of quantification (LOQ, S/N=10) were in the range of 0.2-1.0 μg/kg and 0.3-3.1 μg/kg, respectively. The average recoveries were 76.4%-116.0% at LOQ, 2-fold LOQ, and 10-fold LOQ levels. The intra-day relative standard deviations (RSDs) were 1.0%-7.9%, and the inter-day RSDs were 1.7%-18.4%. The method is simple, sensitive and accurate, and it is suitable for the determination and quantification of lipid regulators in fish meat.