In this work, a separation/preconcentration method is proposed for the determination of Cd(II) and Pb(II) in swimming pool waters, using ammonium pyrrolidine dithiocarbamate (APDC) as a complexing agent and unloaded polyurethane foam (PUF) as a sorbent. The proposed method was optimized, and the defined optimal conditions were a pH of 7, 30 min of shaking time, 400 mg of PUF, and 0.5% (m/v) of the APDC solution. The release of Cd(II) and Pb(II) from the solid phase was achieved through the total digestion of PUF using a microwave-assisted acid approach with a 10.5 mol·L−1 HNO3 solution. The methodology was applied to four samples of swimming pool water for the determination of Cd(II) and Pb(II) using graphite furnace atomic absorption spectrometry (GF AAS). The limits of detection and quantification obtained were 0.02 and 0.06 μg·L−1 for Cd(II) and 0.5 e 1.8 μg·L−1 for Pb(II), respectively. We analyzed four samples of swimming pool waters, finding Cd concentrations between 0.22 and 1.37 μg·L−1. On the other hand, only one sample presented Pb concentration above the limit of quantification (11.4 μg·L−1). Recovery tests were performed by spiking the samples with known concentrations of the analytes, and recovery percentages between 82% and 105% were obtained.

Coal-fired power plant fly ash is a global environmental concern due to its small particle size, heavy metal content, and increased emissions. Although widely used in concrete, geopolymer, and fly ash brick production, a large amount of fly ash remains in storage sites or is used in landfills due to inadequate raw material quality, resulting in a waste of a recoverable resource. Therefore, the ongoing need is to develop new methods for recycling fly ash. The present review differentiates the physiochemical properties of fly ash from two coal combustion processes: fluidized bed combustion and pulverized coal combustion. It then discusses applications that can consume fly ash without strict chemical requirements, focusing on firing-associated methods. Finally, the challenges and opportunities of fly ash recycling are discussed.

Point-of-care technology (POCT) is an important method in clinical testing in the future, which can achieve the purpose of rapid analysis. In this work, we assembled an electrochemical POC sensor for uric acid (UA) by surface modification of a screen-printed electrode. Copper nanowires were used as electrode modifiers to achieve high-performance electrochemical oxidation of UA. This electrochemical sensor can achieve linear detection of UA in the range of 10 μM to 2 mM. The detection limit of the sensor was calculated to be 2 μM. Although the detection performance of this sensor is not competitive with high-performance electrochemical sensors, it has been able to meet the needs of POC detection. At the same time, the sensor has excellent anti-interference performance. It has also been used successfully to test urine and serum samples from healthy and gout patients.

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 r2 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.

Shaoyao-Gancao Decoction (SGD) is a well-known classic traditional Chinese medicine (TCM) with antispasmodic, anti-inflammatory, and analgesic effects. This preparation has been widely used to treat spasticity diseases in the clinic. To date, the material basis of SGD remains unclear, and the spectrum-effect correlation of its antispasmodic activity has not been reported yet. In this study, high-performance liquid chromatography (HPLC) was used to establish the fingerprint and determine the multiple components of SGD. The common peaks of fingerprints were evaluated by the similarity with the chromatographic fingerprints of the TCM. Meanwhile, the multiple components were quantified and analysed using the heatmap and box size analysis. Furthermore, data on the antispasmodic effect were extracted through in vitro smooth muscle contraction assay. Grey relational analysis combined with partial least square regression was used to study the spectrum–effect correlation of SGD. Finally, the potential antispasmolytic components were validated using an isolated tissue experiment. The HPLC fingerprint was established, and 20 common peaks were identified. The similarities of 15 batches of SGD were all above 0.965. The HPLC method for simultaneous determination of the multiple components was accurate and reliable. The contents of albiflorin, paeoniflorin, liquiritin, and glycyrrhizic acid were higher than the other components in SGD. The heatmap and box size also showed that X3 (albiflorin), X4 (paeoniflorin), X5 (liquiritin), X11 (liquirtigenin), and X16 (glycyrrhizic acid) could be used as quality indicators in the further establishment of quality standards. The spectrum–effect correlation results indicated that X4, X11, and X16 were highly correlated with antispasmolytic activity. Verification tests showed that paeoniflorin (11.7–29.25 μg/mL) and liquirtigenin (17.19–28.65 μg/mL) could significantly reduce the maximum contractile (). These compounds exerted concentration-dependent spasmolytic effects with the inhibitory response for acetylcholine (Ach)-evoked contraction. Thus, SGD had a significant antispasmodic effect, which resulted from the synergistic activity of its multiple components. These findings can be used for the pharmacodynamics study of SGD and are of great significance for the determination of quality markers and quality control.

The predominant objective of the research is to establish the anti-inflammatory and analgesic spectrum-effect relationship of Chloranthus fortunei (A. Gray) Solms-Laub (CF), to reveal the pharmacodynamic basis of the anti-inflammatory and analgesic effects of CF. The fingerprints of ten batches of CF from various origins were established by high-performance liquid chromatography (HPLC) and evaluated for similarity, hierarchical cluster analysis (HCA), and principal component analysis (PCA). The anti-inflammatory and analgesic effects of CF were evaluated with the xylene-induced ear swelling in mice and the acetic acid torsion test, while the anti-inflammatory and analgesic spectrum-effect relationship of CF was evaluated by gray relational analysis (GRA) and partial least squares regression analysis (PLSR) to effectively elucidate the anti-inflammatory and analgesic substance basis of CF. The ten batches of CF HPLC fingerprints established in this work successfully identified a total of 13 common peaks that refer to 4 components, with peak 1 being neochlorogenic acid, peak 3 being chlorogenic acid, peak 5 being cryptochlorogenic acid, and peak 10 being rosmarinic acid. The HCA results presented that the ten batches of CF samples were clustered into 3 categories, which was consistent with the PCA results. Simultaneously, the results of the spectrum-effect relationship also indicated that neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, and rosmarinic acid were the possible anti-inflammatory and analgesic substances of CF. In order to better understand the anti-inflammatory and analgesic substance basis of CF, this experiment established the anti-inflammatory and analgesic spectrum-effect relationship of CF, which can provide a scientific foundation for the quality evaluation and further research as well as the usage of CF herbs.

Dalbergia hancai Benth. (D. hancai) is one of the most frequently utilized traditional Chinese medicine in Zhuang medicine. Simultaneously, it has been included in the “Quality Standard of Zhuang medicine in Guangxi Zhuang Autonomous Region (Vol. 2)” and possessed outstanding pharmacological effects. However, the pharmacodynamic material basis of D. hancai still remains unclear. In this study, the high-performance liquid chromatography (HPLC) method had been employed to establish the fingerprint of 10 batches of aqueous extract of D. hancai originated from different parts of China. At the same time, similarity evaluation, cluster analysis, and principal component analysis (PCA) had also been conducted to evaluate the common peaks. The acetic acid-induced writhing in mice had been employed as an analgesic model, and the carrageenan-induced toe swelling in mice was utilized as an anti-inflammatory model for pharmacodynamic experiments. The gray relational analysis (GRA) and partial least squares regression (PLSR) were applied to correlate the fingerprint and pharmacodynamic data to thoroughly examine its spectrum-effect relationship, whereby its analgesic and anti-inflammatory material basis had been comprehensively explored. The results revealed that the HPLC fingerprint of the aqueous extract of D. hancai had successfully identified 12 common peaks whereby two of which were further identified as protocatechuic acid and vitexin. Subsequently, through the analysis of GRA and PLSR, the chromatographic peaks that possess a critical correlation degree with the analgesic and anti-inflammatory effects of D. hancai had also been successfully discovered. Ultimately, the analgesic and anti-inflammatory effects of the 10 batches of D. hancai aqueous extract had been conclusively proved, and it was evidently indicated that these effects were attributable to the synergistic interactions between various components. Therefore, this study aims to serve as an effective analytical method for screening and predicting the effective substances of traditional Chinese medicine on the basis of the spectrum-effect relationship.

Tetracycline is a broad-spectrum class of antibiotics. The use of excessive doses of tetracycline antibiotics can result in their residues in food, posing varying degrees of risk to human health. Therefore, the establishment of a rapid and sensitive field detection method for tetracycline residues is of great practical importance to improve the safety of food-derived animal foods. Electrochemical analysis techniques are widely used in the field of pollutant detection because of the simple detection principle, easy operation of the instrument, and low cost of analysis. In this review, we summarize the electrochemical detection of tetracycline antibiotics by bibliometrics. Unlike the previously published reviews, this article reviews and analyzes the development of this topic. The contributions of different countries and different institutions were analyzed. Keyword analysis was used to explain the development of different research directions. The results of the analysis revealed that developments and innovations in materials science can enhance the performance of electrochemical detection of tetracycline antibiotics. Among them, gold nanoparticles and carbon nanotubes are the most used nanomaterials. Aptamer sensing strategies are the most favored methodologies in electrochemical detection of tetracycline antibiotics.

To study the differences in phenolic compounds between tobacco smokers’ saliva and mainstream smoke, a method was developed for the analysis of 12 phenolic compounds in saliva and mainstream smoke based on ultrahigh-performance liquid chromatography with fluorescence detection (UPLC-FLD). The contents and distributions of phenolic compounds in tobacco smokers’ saliva and mainstream smoke were compared. The results were as follows: (1) Phenolic compounds were quantitatively analyzed by the internal standard method using 4-fluorophenol as an internal standard. For smokers’ saliva samples, the limits of quantification (LOQs) ranged from 2.2 to 19.1 μg/L, and the recoveries were from 80.2% to 119.2% at the three spiked levels. For mainstream smoke samples, the LOQs ranged from 0.03 to 0.26 μg/cig, and the recoveries ranged from 84.9% to 107.0% at the three spiked levels. (2) The contents of phenolic compounds from 14 cigarettes in mainstream smoke and smokers’ saliva were determined. In mainstream smoking, the main phenolic compounds were hydroquinone, catechol, phenol, meta- and para-Cresol, and o-methylhydroquinone. In smokers’ saliva, the main phenolic compounds were phenol and meta- and para-Cresol and the contents of phenolic compounds in smokers’ saliva from different cigarettes were significantly different. (3) The content distribution patterns of phenolic compounds in smokers’ saliva differed from those in mainstream smoke. The predominant phenolic compound in mainstream smoke was dihydroxybenzene, while monophenols predominated in smokers’ saliva. (4) The contents of phenolic compounds from five kinds of cigarettes were analyzed in the saliva of different smokers using principal component analysis, which indicated that cigarettes with different sensory effects were clearly distinguished by differences in the contents of phenolic compounds in saliva.

Background. Naolingsu capsule (NLSC) is a well-known traditional Chinese medicine (TCM) prescription in China. It is widely used to treat neurasthenia, insomnia, cardiovascular and cerebrovascular disease, and other diseases. However, its inalienable chemical groups have not been carried out. Methods. We first established the nontargeted investigation based on fingerprinting coupled with UHPLC-Q/TOF-MS/MS. Second, the quantitative methods based on HPLC-DAD and LC-MS/MS were connected to the synchronous quantitative assurance of eleven and fourteen marker compounds. Finally, the quantitative information was processed with SIMCA-P for differentiating the distinctive bunches of samples to screen the foremost appropriate chemical markers. Results. The similarity of HPLC fingerprints of 24 batches of NLSC samples was 0.645–0.992. In total, 37 flavonoids, 21 organic acids, 22 lignans, 13 saponins, and 20 other compounds were recognized in NLSC by the UHPLC-Q/TOF-MS/MS method. The quantitative determination was approved for linearity, discovery limits, accuracy, repeatability, soundness, and precision. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) models accomplished the great classification of the samples from the five enterprises, respectively. Rehmannioside D (RD), methylophiopogonanone A (MPA), 3,6′-disinapoyl sucrose (DS), schisandrin B (SSB), epimedin C (EC), icariin (ICA), and jujuboside B (JB) were considered as the potential chemical markers for NLSC quality control. Conclusion. The experimental results illustrated that the combinative strategy was valuable for quick pharmaceutical quality assessment, which can potentially differentiate the origin, decide the realness, and assess the overall quality of the formulation.

A method based on elemental fingerprint, stable isotopic analysis and combined with chemometrics was proposed to trace the geographical origins of Licorice (Glycyrrhiza uralensis Fisch) from 37 producing areas. For elemental fingerprint, the levels of 15 elements, including Ca, Cu, Mg, Pb, Zn, Sr, Mn, Se, Cd, Fe, Na, Al, Cr, Co, and K, were analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES). Three stable isotopes, including δ13C, δ15N, and δ18O, were measured using an isotope-ratio mass spectrometer (IRMS). For fine classification, three multiclass strategies, including the traditional one-versus-rest (OVR) and one-versus-one (OVO) strategies and a new ensemble strategy (ES), were combined with two binary classifiers, partial least squares discriminant analysis (PLSDA) and least squares support vector machines (LS-SVM). As a result, ES-PLSDA and ES-LS-SVM achieved 0.929 and 0.921 classification accuracy of GUF samples from the 37 origins. The results show that element fingerprint and stable isotope combined with chemometrics is an effective method for GUF traceability and provides a new idea for the geographical traceability of Chinese herbal medicine.

The miniaturization of analytical systems and the utilization of nontoxic natural extract from plants play significant roles for green analytical chemistry methodology. In this work, the microfluidic hydrodynamic sequential injection (HSI) with the LED-phototransistor colorimetric detection system has been proposed to create an ecofriendly and low-cost miniaturized analytical system for online determination of iron in water samples using Curcuma putii Maknoi & Jenjitt. extracts as high stability and good selectivity of a natural reagent. The proposed method was designed for online solution mixing and colorimetric detection on a microfluidic platform. The Curcuma putii Maknoi & Jenjitt. extracts and standard/samples were sequentially aspirated to fill the channel before entering the built-in flow cell. The intensity of iron-Curcuma putii Maknoi & Jenjitt. extract complex was monitored under the optimum conditions of flow rate, sample volume, mixing zone length, and aspiration sequences, by altering the gain control of the colorimetric detector to achieve good sensitivity. The results demonstrated a good performance of the green analytical systems. A linear calibration graph in the range of 0.5–6.0 mg L−1 was obtained with a limit of detection at an adequate level of 0.11 mg L−1 for water samples with a sample throughput of 30 h−1. The precise and accurate measurement results were achieved with relative standard deviations in the range of 1.61–1.72%, and percent recoveries were found in the range of 90.6–113.4. The proposed method offers cost-effective, easy operation over an appropriate analysis time (2 min/injection) with good sensitivity and is environmentally friendly with low consumption of solutions and the use of high stability and good selectivity of nontoxic reagents. The achieved method was demonstrated to be a good choice for routine analysis.

Medical providers are increasingly confronted with clinical decision-making that involves (meth)amphetamines. And clinical laboratories need a sensitive, efficient assay for routine assessment of D- and L-isomers to determine the probable source of these potentially illicit analytes. This paper presents a validated method of D- and L-isomer detection in human oral fluid from an extract used for determination of a large oral fluid assay (63 analytes) on an older AB SCIEX 4000 instrument. Taken from the positive extract, D- and L-analytes were added. The method for extraction included addition of internal standard and a 2-step liquid-liquid extraction and dry-down step to concentrate and clean the samples. The samples were suspended in 50% MeOH in water, diluted with mobile phase, with separation and detection accomplished using LC-MS/MS to determine analyte concentration. Once samples were confirmed positive for (meth)amphetamine from the large oral fluid assay, they were further examined for the enantiomeric forms with 50 μl aliquots of the standards and samples of interest combined with 450 μl of D- and L-assay mobile phase, then analyzed using chiral column separation, and LC-MS/MS detection with standard curve spanning the range from 2.5 to 1000 ng/mL. The result is a sensitive and accurate detection of D- and L-isomers of amphetamine and methamphetamine in human oral fluid performed on an older model mass spectrometer (AB SCIEX 4000). The novelty of this assay is twofold (a) the 2-step liquid-liquid extraction and dry-down step to concentrate and clean the samples, and (b) its adoption characteristics as a reflex test from a large ODT panel without the need to invest in newer or expensive LC-MS/MS instruments. Finally, this assay also has potential to add a valuable option to high-throughput laboratories seeking a D- and L-testing alternative to urine drug testing methods.

Color pigments from plant, animal, or mineral sources can be identified, separated, and quantified for various purposes. It is expected that pigments from Beta vulgaris L. peels and pomaces could be used to develop natural dyes that can find applications in areas such as food or textile dyeing industries. This work aimed at identifying and quantifying the pigment in the B. vulgaris L. peels and pomaces extracts as well as validating the method by high-performance liquid chromatography combined with ultraviolet spectroscopy (HPLC-UV) and ultra-high-performance liquid chromatography coupled with triple quadrupole (TSQ) mass spectrometry (UHPLC-MS/MS). Column chromatography was used to isolate compounds after methanolic solvent extraction. Identification and quantification of the pigments in the extract were achieved using reverse-phase HPLC with a UV detector (538 nm). The UHPLC-MS/MS was used for further confirmation of colored compounds in the extract. Method validation included the use of betanin standard (betanidin 5-β-D-glucopyranoside), determination of repeatability (precision), calibration curve linearity, and sensitivity (LOD and LOQ) tests. Betanin was detected in the sample at retention times of 7.699 and 7.71 minutes, respectively, which closely matched the tR (7.60 min) of the standard, according to HPLC-UV and LC-MS/MS data. The average betanin concentration was 3.81 0.31 mg/g of dry weight, according to the HPLC-UV analysis. The LC-MS/MS data revealed the existence of several compounds, including betanin (4.31 ± 2.15 mg/g), isobetanin (1.85 ± 2.20 mg/g), 2, 17-bidecarboxy-neobetanin (0.71 ± 0.02 mg/g), betanidin (0.71 ± 0.03 mg/g), 2-O-glucosyl-betanin (0.40 ± 0.10 mg/g), and isobetanidin (0.36 ± 1.26 mg/g), among other compounds whose yields were too low. In conclusion, the peels and pomaces of B. vulgaris L. can be a useful source for the extraction of a red dye for use in coloring, such as the dyeing of textile substrates.

Objective. Because the response of evaporating light scattering detector (ELSD) being in a nonlinear mode, there is no consensus on the method of calculating its relative correction factors (RCF), which limits the application of the quantitative analysis for multi-components by a single marker (QAMS) with LC-ELSD. Methods. Using eight fructooligosaccharides of Morinda officinalis as a case study, the nystose (GF3) as a single standard was adopted to develop a QAMS method to simultaneously determine the other seven fructooligosaccharides with HILIC-HPLC-ELSD method. Six calculation methods of RCF were investigated to select the most reasonable method. The relative error of content between the QAMS and the external standard method (ESM) obtained from 30 batches of samples was used as an indicator to evaluate the six methods. Finally, a chemometrics analysis was performed to find the differential components among MO and its three processing products. Results. It was first reported that only one calculation method was scientific for calculating RCF for the LC-ELSD method. The RCFs of GF3 to the other seven fructooligosaccharides (GF1–GF8) were obtained as 0.86, 0.91, 0.93, 1.05, 1.15, 1.12, and 1.18, respectively. The QAMS of eight fructooligosaccharides of Morinda officinalis was validated with good linearity (R2 > 0.9998) and accepted the accuracy of 95–105% (RSD < 1.81%) based on nystose. Finally, Morinda officinalis and its three processed products were distinguished and could be differed based on the content of the eight fructooligosaccharides. Conclusion. The scientific calculation method of RCF would be of great significance for developing the QAMS method in Pharmacopoeia when performing the LC-ELSD method.

In this study, a magnetic metal-organic framework (MOF) was synthesized based on magnetic Fe3O4, Cu(II), and benzene-1,3,5-tricarboxylic acid (Cu-BTC) as a sorbent for solid phase extraction (SPE) of trace amounts of Pb(II) in water and lettuce samples. Pb(II) ion was adsorbed on the magnetic MOF and easily separated by a magnet; therefore, no filtration or centrifugation was necessary. The analyte ions were eluted by HCl 0.5 mol·L−1 and analyzed via graphite furnace atomic absorption spectroscopy. The prepared sorbent was characterized by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and Fourier transform-infrared (FT-IR) spectroscopy. Under optimal experimental conditions, the method had a linear range of 0.1–50 μg·L−1. The limits of detection and quantitation for lead were found to be 0.026 and 0.08 μg·L−1, respectively. The results showed that the prepared sorbent has high selectivity for Pb2+ even in the presence of other interfering metal ions.

Analysis of trace elements and heavy metals in honey is essential for honey quality and safety and also monitoring environmental pollution. This study aimed to evaluate the composition of thirty-seven honey samples of different botanical origins (14 multifloral and 23 unifloral) obtained from beekeepers located in the west region of Algeria. Inductively coupled plasma-mass spectrometry (ICP-MS) and atomic absorption spectroscopy (AAS) methods were used to determine the levels of 19 elements in honey (K, Na, Ca, Mg, Mn, Cu, Fe, Zn, V, Cr, Co, As, Ru, Rh, Cd, W, Pt, Au, and Pb). Ru, Rh, Pt and, Au were not detected in any of the tested honey samples. The most abundant minerals were K, Ca, Na, and Mg ranging within 153.00–989.00 mg/kg, 33.10–502.00 mg/kg, 13.30–281.00 mg/kg, and 20.80–162.00 mg/kg, respectively. Fe, Mn, Zn, and Cu were the most abundant heavy metals while Pb, V, Cr, W, Co, and Cd were the lowest ones (<1 mg/kg) in the honey samples surveyed. Several honey types, lavender, rosemary, mild white mustard, thyme, milk thistle, carob tree, orange tree, Euphorbia, Eucalyptus, camphor, jujube tree, sage, and harmal, were studied, and the statistical analysis was carried out using principal component analysis (PCA) and hierarchical cluster analysis (HCA) techniques to evaluate the data. The results showed that the analyses of mineral content were sufficient to determine the floral origin and their variability may be related to geochemical and geographical differences. On other hand, all elements detected were at levels below safe thresholds.

The HPTLC method is widely used in the field of quality evaluation and component analysis of traditional Chinese medicine (TCM). This work developed an HPTLC method to determine the five effective components of osthole, columbianadin, isoimperatorin, oxypeucedanin, and imperatorin in Angelicae Pubescentis Radix (APR) from twelve different origins, and the quality difference was analyzed by comprehensive factor analysis and cluster analysis. The results showed that the calibration curves of five components exhibited good linearity within the linear ranges (0.8–4.0 μg). The RSD of precision was 1.06%–1.21%, and the repeatability and stability tests were good. The results of cluster analysis showed that the APR from 12 different areas was divided into two categories, and at the same time, it was found that the quality of Dazhou in Sichuan and Huating in Gansu was better than in other areas. In this study, a simple, rapid, and efficient method for quality evaluation of TCM was established by the HPTLC method.

Simple, accurate, precise, and cost-effective chemometric techniques for the measurement of candesartan cilexetil and hydrochlorothiazide in synthetic mixtures were improved and validated. H-point standard addition, Q-absorption ratio, and correction absorbance spectrophotometric techniques were utilized for the simultaneous determination of both medicines in real pharmaceutical formulations. A new calibration approach was implemented based on chemical H-point standards. This approach was developed to resolve significantly overlapping spectra of two analytes and provide direct correction of both proportional and constant errors caused by the matrix of the sample. The first method of simultaneous determination of candesartan cilexetil and hydrochlorothiazide was carried out using the H-point standard addition method at wavelengths 239 and 283. For the ratio of the absorption at two selected wavelengths, one of which is the isoabsorptive point and the other being the maximum of one of the two components, the second method absorption ratio method was utilized. In distilled water, the isoabsorptive point of candesartan cilexetil and hydrochlorothiazide occurs at 258 nm. λmax of hydrochlorothiazide is 273 nm, which is the second wavelength used. Lastly, the absorbance correction method was implemented. This approach is based on absorbance correction equations and uses distilled water as the solvent for the examination of both medicines. In NaOH/EtOH solvent, the absorbance maxima of candesartan cilexetil and hydrochlorothiazide are 250 nm and 340 nm, respectively. For both wavelengths, candesartan cilexetil and hydrochlorothiazide exhibited linearity over a concentration range of 1–46 μg/ml and 1–44 μg/ml, respectively, for H-point standard addition. The Q-absorption ratio approach provides linearity over the concentration ranges of 1–46 μg/ml at 273 nm for candesartan cilexetil and 1–29 μg/ml for hydrochlorothiazide, 1–46 μg/ml at 258 nm for candesartan cilexetil, and 1–44 μg/ml for hydrochlorothiazide. For hydrochlorothiazide, the linearity for the correction absorbance method was obtained throughout a concentration range of 1–46 μg/ml at wavelengths 250 and 340 nm and 1–44 μg/ml at wavelength 250 nm. The results of the analysis have been statistically and empirically supported by recovery studies. All methods yielded recoveries in the range of 96 ̶102% for both medications. The LOD ranged from 0.46 ̶0.94 μg/mL for hydrochlorothiazide and from 1.26 ̶2.40 μg/mL for candesartan cilexetil. The approaches were then used to quantify candesartan cilexetil and hydrochlorothiazide in pharmaceutical tablets.

Yinqiao powder, with significant anti‐inflammatory and antiviral effects, is a classical formula for the treatment of febrile diseases in China. During the SARS period in 2003, Yinqiao powder showed a good antipyretic effect. It also plays a major role in the treatment for COVID-19 in China. Although there are many studies on the chemical compositions and pharmacological effects of Yinqiao powder, there are few studies on the quality standard system of it. In our study, a systematic quality evaluation method of Yinqiao powder combining HPLC fingerprint with quantitative analysis of multi-components by single marker (QAMS) based on network pharmacology and UPLC-Q-Exactive-Orbitrap-MS was established for the first time. In the UPLC-Q-Exactive-Orbitrap-MS experiment, a total of 53 compounds were identified in the extract solution of Yinqiao powder. In addition, 33 blood components were characterized, 23 of which were prototypes. The results of network pharmacology analysis showed that Yinqiao powder may inhibit inflammatory responses by suppressing IL-6, CXCL2, TNFα, NF-κB, etc., in the treatment of COVID-19. The HPLC fingerprint analysis of Yinqiao powder was conducted at 237 nm and 29 characteristic peaks were matched, 11 of which were identified. Forsythoside A was selected as the internal standard reference and double-wavelength (237 nm and 327 nm) was established in QAMS experiment. The repeatability was well under different conditions, and the results measured by QAMS were consisted with that of the external standard method (ESM), indicating that the QAMS method was reliable and accurate. The quality evaluation method of Yinqiao powder would be helpful to evaluate the intrinsic quality of Yinqiao powder more comprehensively, which is conducive to improve the quality standard of Yinqiao powder and provide a beneficial guarantee for the clinical treatment of COVID-19.