Quantitative Determination Research Articles

A versatile economic strategy by HPLC–CAD for quantification of structurally diverse markers in quality control of Shengmai Formula from raw materials to preparations

BackgroundShengmai Formula (SMF), a classic formula in treating Qi-Yin deficiency, is composed of Ginseng Radix et Rhizoma Rubra (GRR), Ophiopogon Radix (OR), and Schisandra chinensis Fructus (SC), and has been developed into various dosage forms including Shengmai Yin Oral Liquid (SMY), Shengmai Capsules (SMC), and Shengmai Injection (SMI). The pharmacological effects of compound Chinese medicine are attributed to the integration of multiple components. Yet the quality criteria of SMF are limited to monitoring schisandrol A or ginsenosides Rg1 and Re, but none for OR. Since the complexity of raw materials and preparations, establishing a economical and unified method for SMF is challenging. It is urgent to simultaneously quantify multiple components with different structures using a universal method for quality control of SMF. Charged aerosol detector (CAD) overcame the above shortcomings owing to its characteristics of high responsiveness, nondiscrimination, and low cost. PurposeWe aimed to establish a versatile analysis strategy using HPLC–CAD for simultaneously quantifying the structurally diverse markers in quality control of SMF from raw materials to preparations. MethodBy optimizing the column, mobile phase, column temperature, flow rate, and CAD parameters, a HPLC-CAD method that integrated multi-component characterization, authenticity identification, transfer information of raw materials and quantitative determination of Shengmai preparations was established. ResultsIn total 50 components from SMF were characterized (28 in GRR, 13 in SC, and 9 in OR). The differences in raw materials between species of SC and Schisandrae sphenantherae Fructus (SS), processing methods of Ginseng Radix (GR) and GRR, and locations of OR from Sichuan (ORS) and Zhejiang (ORZ) were compared. Fourteen components in 19 batches of SMY, SMC and SMI from different manufacturers were quantified, including 11 ginsenosides and 3 lignans. The multivariate statistical analysis results further suggested that Rb1, Rg1 and Ro were the main differences among Shengmai preparations. ConclusionThe established versatile analysis strategy based on HPLC–CAD was proven sensitive, simple, convenient, overcoming the discriminatory effect of UV detector, revealing the composition and transfer information of SMF and applicable for authentication of the ingredient herbs and improving the quality of Shengmai preparations.

Illuminating Polysulfide Distribution in Lithium Sulfur Batteries; Tracking Polysulfide Shuttle Using Operando Optical Fluorescence Microscopy.

High-energy-density lithium sulfur (Li-S) batteries suffer heavily from the polysulfide shuttle effect, a result of the dissolution and transport of intermediate polysulfides from the cathode, into the electrolyte, and onto the anode, leading to rapid cell degradation. If this primary mechanism of cell failure is to be overcome, the distribution, dynamics, and degree of polysulfide transport must first be understood in depth. In this work, operando optical fluorescence microscope imaging of optically accessible Li-S cells is shown to enable real-time qualitative visualization of the spatial distribution of lithium polysulfides, both within the electrolyte and porous cathode. Quantitative determinations of spatial concentration are also possible at a low enough concentration. The distribution throughout cycling is monitored, including direct observation of polysulfide shuttling to the anode and consequent dendrite formation. This was enabled through the optimization of a selective fluorescent dye, verified to fluoresce proportionally with concentration of polysulfides within Li-S cells. This ability to directly and conveniently track the spatial distribution of soluble polysulfide intermediates in Li-S battery electrolytes, while the cell operates, has the potential to have a widespread impact across the field, for example, by enabling the influence of a variety of polysulfide mitigation strategies to be assessed and optimized, including in this work the LiNO3 additive.

Quantitative determination of R/S-methadone in human serum using ultra-high performance supercritical fluid chromatography-tandem mass spectrometry: A method for routine use.

Methadone has two enantiomers, which exhibit differences in pharmacological effects, with R-methadone being the active and S-methadone the inactive enantiomer. A robust, simple and rapid method for chiral separation of the two enantiomers in serum samples using ultra-high performance supercritical fluid chromatography-tandem mass spectrometry (UHPSFC-MSMS) has been developed and validated. Enantiomeric separation was achieved using a Chiralpak IH-3 column with a mobile phase consisting of CO2 and 30mM ammonium acetate in methanol/water (98/2, v/v). Runtime was 4minutes. Sample preparation was semi-automated using a Hamilton ML Star robot with protein precipitation, and phospholipid removal was carried out using a Waters OSTRO™ 96-well plate. The calibration range was 50.0-1,500 nM for each enantiomer. The between-assay relative standard deviations were in the range of 1.2-3.6%. Matrix effects ranged from 99% to 115% corrected with internal standard. The method has been implemented in our laboratory and has proven to be a robust and reliable method for determining the ratio of R/S-methadone in authentic patient samples.

Cu/Mn Synergy Catalysis-Based Colorimetric Sensor for Visual Detection of Hydroquinone

The reliable detection of environmental contaminants can correctly forecast the degree of environmental pollution that has occurred, which contributes to improving the environmental purification rate and maintaining the ecological balance. Herein, a novel hierarchical biomimetic catalysis MnO2@CuAl-CLDHs was designed and synthesized using a facile method, which exhibited significantly enhanced peroxidase-like activity due to the unique composition and hierarchical mesoporous structure. Under optimized operational conditions, a visible colorimetric array based on the superior nanozyme activity of MnO2@CuAl-CLDHs was developed for the quantitative determination of hydroquinone with a wide linear detection range (1–100 μM) and a low detection limit (0.183 μM). Simultaneously, our presented strategy could analyze hydroquinone in real water samples with high accuracy. Therefore, the bimetallic co-catalyzed nanozymes are expected to be the perfect replacement for natural enzymes to develop convenient and efficient sensors.

Effect of Hydrogen Addition on Coke Formation and Product Distribution in Catalytic Coupling of Methane.

The effect of hydrogen addition on catalytic nonoxidative coupling of methane at 1000 °C was investigated. Experiments were performed at varying ratios between the catalyst and the postcatalytic volume to discern the effect of hydrogen on the catalytic reaction as well as on the gas-phase reaction. Adding 10% H2 decreases the methane conversion by a factor of 2, almost independent of the ratio between the catalyst and the postcatalytic residence time. The effect on the conversion is mostly determined by gas-phase chemistry. Hydrogen addition has no influence on the C2 hydrocarbon yield, whereas aromatic selectivity is significantly reduced. Changes in selectivity are attributed to changes in methane conversion. Quantitative determination of the amount of coke deposited on the catalyst reveals a decrease by 1 order of magnitude when dosing up to 10% H2, while carbon deposits-downstream of the catalyst bed are suppressed to a much lower extent. These results suggest a process in which the produced hydrogen is partly recycled, maximizing the carbon selectivity to C2 hydrocarbons while minimizing both aromatics and, most crucially, formation of coke on the catalyst as well as further deposits-downstream.

Innovative approach for quantitative determination of ingested microplastics by Daphnia magna: use of differential scanning calorimetry and thermogravimetry

AbstractDue to the serious environmental impacts of plastic pollution, some conventional plastics have been replaced with biodegradable alternatives. However, these biodegradable options can also fragment and form microplastics, which can be ingested by and harm various biota. The standard methods for quantifying ingested microplastics involve digestion of the gut or the whole organism using acidic, alkaline, or oxidative processes. However, these aggressive methods may destroy biodegradable microplastics, leading to erroneous results. Therefore, in this study, we employed thermal analysis methods, specifically differential scanning calorimetry (DSC) and thermogravimetry (TG), to quantify the ingestion of poly-3-hydroxybutyrate (P3HB), a biodegradable microplastic, by the freshwater crustacean, Daphnia magna. During chronic experiments, we analysed organisms exposed to P3HB with sizes smaller than 125 and 63 μm, at concentrations ranging from 1.56–25 mg L−1. DSC identified an endothermic peak associated with the melting of semicrystalline P3HB, and its enthalpies were utilised to compute the number/mass of P3HB ingested by D. magna. Notably, shifts in melting points suggested that higher concentrations induced particle agglomeration, and these agglomerates could not penetrate deeply into the organism. The TG approach involved subtracting the mass loss between 200 and 400 °C in D. magna specimens exposed to P3HB suspensions from controls without P3HB exposure. Both methods provided comparable data, revealing that, depending on particle size, individual D. magna ingested up to 10% of their body mass. Our findings indicate that both methods effectively detect P3HB (and potentially other plastic fragments), with DSC demonstrating better sensitivity. While the suggested approach did not enable us to calculate the level of determination or quantification, we were able to demonstrate that DSC can detect P3HB in only one specimen of D. magna exposed to the lowest suspension concentration. This indicates that D. magna exposed to the 63 μm fraction ingested approximately 3 μg of P3HB, whereas those exposed to the 125 μm P3HB ingested around 4 μg of P3HB. The introduced methods expand the possibilities for detecting ingested microplastics and probably also nanoplastics, in zooplankton and possibly also other species.

Evaluation of Pesticides and Trace Metal Contaminants in Grains, Fresh Fruits and Vegetables from Odoluwa Market Ile Oluji; Ondo State Nigeria

Vegetables, fruits and grains are sources of food rich in vitamins, minerals, and fibers and also have beneficial ant oxidative effects Pesticides and trace metals typically contaminate these food products. Pesticides and trace metals are not biodegradable and have the potential for accumulation in different body organs, leading to unwanted side effects This study investigated the concentration of pesticide residues and some selected Trace metals in Vegetables, fruits and grains from Odolua market Ile-Oluji Ondo State. Samples were collected randomly from the market, representative portion of the samples was chopped into small pieces and blended using a blender..Quantitative determination of the pesticide for Herbicides, organochlorine and organophosphate was carried out using Gas Chromatography-Mass Spectrometer after liquid-liquid extraction. Trace Metal was determined using Inductively coupled plasma - optical emission spectrometry (ICP-OES). The results reveal the presence of pesticide residues in all the samples. The mean concentration of pesticides in the samples was below the maximum residue limits (MRs) value for World health organization (WHO) while some were higher. The results also shows that all the trace metals analyzed are present in the samples except for Cadmium which is below the detection limit while Lead and Cobalt are only detected in one sample each. Some concentrations of the trace metals were below the permissible limit for WHO while others were higher than the permissible limit.

Spectrophotometric Determination of Hydroxycinnamic Acids in Herbal Drugs. Part 2. Determination of Hydroxycinnamic Acids in the Presence of Polyphenolic Compounds (Review)

INTRODUCTION. Polyphenolic compounds of various classes have pronounced absorption bands overlapping in almost the same ultraviolet region. This superposition of bands complicates the quantification of total hydroxycinnamic acids in herbal drugs by direct spectrophotometry without additional sample preparation.AIM. This study aimed to establish the possibility of quantifying hydroxycinnamic acids in herbal drugs by spectrophotometry in the presence of other polyphenolic compounds.DISCUSSION. This review analyses publications on analytical procedures for the spectrophotometric quantification of hydroxycinnamic acids that are based on the preliminary separation or chemical modification of polyphenolic compounds (combining the use of spectrophotometry, chromatography, extraction, Arnow’s reagent, etc.). The described sample preparation can help to resolve absorption bands in the spectra of polyphenolic compounds. The results of assessing the characteristic parameters of these analytical procedures (selectivity, sensitivity, labour intensity, etc.) can serve as a basis for searching novel approaches to the quantitative determination of hydroxycinnamic acids in plants.CONCLUSIONS. To determine the content of hydroxycinnamic acids in mixtures of polyphenolic compounds, analysts may use special sample preparation (combining spectrophotometry with chromatography and extraction) or chemical modification of the initial compounds. The acquired spectra could benefit from specific mathematical processing (derivative photometry and Vierordt’s method). However, even with the abovementioned approaches, it may not always be possible to increase the selectivity of an analytical procedure. Therefore, there is a need to further improve existing analytical procedures for the quantification of hydroxycinnamic acids and develop new ones.

Quality control methods for fruit extracts of Kigelia africana using high performance thin layer chromatography

Kigelia africana is a tree native to Africa but also found in eastern and southern parts of India with reported anti-bacterial, anti-inflammatory, and immunomodulatory activities. Verbascoside, caffeic acid and ferulic acid are important markers for the quality control of the plant. Two different HPTLC methods were developed and validated; method − 1 for estimation of verbascoside and caffeic acid while method − 2 for estimation of caffeic acid and ferulic acid. Developed methods were applied to the methanolic fruit extract to determine the quantities of markers. Both methods were found to be linear, specific, precise, accurate, sensitive and robust. Results indicated that both methods can be used for quantitative determination of verbascoside, caffeic acid and ferulic acid in fruit extract. The developed methods may be utilised as a part of the quality control and standardisation for the raw material and extracts of Kigelia africana and can also aid to chromatographic fingerprinting of the plant.

Spectrophotometric Determination of Hydroxycinnamic Acids in Herbal Drugs. Part 1. Direct Spectrophotometry (Review)

INTRODUCTION. Current scientific research aims to discover new plant sources of hydroxycinnamic acids for the development of novel medicinal products. Most commonly, the quantitative determination of hydroxycinnamic acids in herbal drugs involves testing procedures based on spectrophotometry and its modifications.AIM. This study aimed to establish the possibility of the quantification of hydroxycinnamic acids in herbal drugs by direct spectrophotometry.DISCUSSION. This review presents organised information on the use of direct spectrophotometry to quantify hydroxycinnamic acids in 70 plant species growing or cultivated in the Russian Federation. The review covers publications in Russian for the period from 2007 to 2023. According to the reviewed publications, direct spectrophotometry is an easy-to-use and highly reproducible method that does not require additional reagents or labour-intensive steps. Direct spectrophotometry may result in an overestimation of the hydroxycinnamic acid content due to overlapping absorption bands of polyphenolic compounds with different structures.CONCLUSIONS. Direct spectrophotometry can be considered as a method for measuring the total content of phenolic compounds (as well as hydroxycinnamic acids) in herbal drugs. Different approaches to direct spectrophotometric quantification of hydroxycinnamic acids in herbal drugs by can serve as a methodological basis for developing analytical procedures specific to the chemical compositions of biologically active compounds in herbal drugs and their extracts.

LC-MS/MS profiling of colon oxysterols and cholesterol precursors in mouse model of ulcerative colitis

Oxysterols and cholesterol precursors are being increasingly investigated in humans and laboratory animals as markers for various diseases in addition to their important functions. However, the quantitative analysis of these bioactive molecules is obstructed by high structural similarity, poor ionization efficiency and low abundance. The current assay methods are still cumbersome to be of practical use, and their applicability in different bio-samples needs to be evaluated and optimized as necessary. In the present work, chromatographic separation conditions were carefully studied to achieve baseline separation of difficult-to-isolate compound pairs. On the other hand, an efficient sample purification method was established for colon tissue samples with good recoveries of sterols, demonstrating negligible autoxidation of cholesterol into oxysterols. The developed UPLC-APCI-MS/MS method was thoroughly validated and applied to measure oxysterols and cholesterol precursors in colon tissue of dextran sulfate sodium (DSS)-induced mouse colitis models, and it is expected to be successfully applied to the quantitative determination of such components in other tissue samples.

Dual amplification for PEC ultrasensitive aptasensing of biomarker HER-2 based on Z-scheme UiO-66/CdIn2S4 heterojunction and flower-like PtPdCu nanozyme

As an important prognostic indicator in breast cancer, human epithelial growth factor receptor-2 (HER-2) is of importance for assessing prognosis of breast cancer patients, whose accurate and facile analysis are imperative in clinical diagnosis and treatment. Herein, photoactive Z-scheme UiO-66/CdIn2S4 heterojunction was constructed by a hydrothermal method, whose optical property and photoactivity were critically investigated by a range of techniques, combined by elucidating the interfacial charge transfer mechanism. Meanwhile, PtPdCu nanoflowers (NFs) were fabricated by a simple aqueous wet-chemical method, whose peroxidase (POD)-mimicking catalytic activity was scrutinized by representative tetramethylbenzidine (TMB) oxidation in H2O2 system. Taken together, the UiO-66/CdIn2S4 based photoelectrochemical (PEC) aptasensor was established for quantitative analysis of HER-2, where the detection signals were further magnified through catalytic precipitation reaction towards 4-chloro-1-naphthol (4-CN) oxidation (assisted by the PtPdCu NFs nanozyme). The PEC aptasensor presented a broader linear range within 0.1 pg mL−1–0.1 μg mL−1 and a lower limit of detection of 0.07 pg mL−1. This work developed a new PEC aptasensor for ultrasensitive determination of HER-2, holding substantial promise for clinical diagnostics.

An efficient method for the extraction and the quantitative determination of callose from HLB-affected and healthy citrus

Callose is a 1,3-β glucan responsible for several processes in planta such as cell division, ripening of pollen mother cells, maintaining the plasmodesmata opening, and providing structure to the sieve plates. Besides the physiological roles, callose is deposited during pathogen attacks, forming papillae to prevent pathogen entrance into the tissue or plugging the sieve pores to limit the spread of phloem pathogens. Candidatus Liberibacter asiaticus (CLas), the putative causal agent of Huanglongbing (HLB), is a phloem-restricted pathogen whose infection leads to the production of callose in the phloem. Characterizing the dynamics of callose plugging during HLB is important for understanding the disease, but no published protocols are available for the extraction and quantification of the callose in citrus trees, and quantitative data are limited. Detection of callose by microscopy is time-consuming and expensive and does not give information about the distribution of callose in the entire plant. Here, we present a short protocol for the efficient extraction and quantification of the total callose from citrus plants. We compared different tissues from healthy and CLas-infected plants and identified an increase in callose levels in the midribs, the stems, and the fruit peduncles of infected plants. Callose levels were highest in leaves, especially midribs, compared to stems, roots, and fruit peduncles. This method could be applied to other woody plant species.

A Dual-Mode Fluorescent Nanoprobe for the Detection and Visual Screening of Pathogenic Bacterial Spores.

Bacterial vegetative cells turn into metabolically dormant spores in certain environmental situations. Once suitable conditions trigger the germination of spores belonging to the pathogenic bacterial category, public safety and environmental hygiene will be threatened, and lives will even be endangered when encountering fatal ones. Instant identification of pathogenic bacterial spores remains a challenging task, since most current approaches belonging to complicated biological methods unsuitable for onsite sensing or emerging alternative chemical techniques are still inseparable from professional instruments. Here we developed a polychromatic fluorescent nanoprobe for ratiometric detection and visual inspection of the pathogenic bacterial spore biomarker, dipicolinic acid (DPA), realizing rapidly accurate screening of pathogenic bacterial spores such as Bacillus anthracis spores. The nanoprobe is made of aminoclay-coated silicon nanoparticles and functionalized with europium ions, exhibiting selective and sensitive response toward DPA and Bacillus subtilis spores (simulants for Bacillus anthracis spores) with excellent linearity. The proposed sensing strategy allowing spore determination of as few as 0.3 × 105 CFU/mL within 10 s was further applied to real environmental sample detection with good accuracy and reliability. Visual quantitative determination can be achieved by analyzing the RGB values of the corresponding test solution color via a color recognition APP on a smartphone. Different test samples can be photographed at the same time, hence the efficient accomplishment of examining bulk samples within minutes. Potentially employed in various on-site sensing occasions, this strategy may develop into a powerful means for distinguishing hazardous pathogens to facilitate timely and proper actions of dealing with multifarious security issues.

Quantitative determination of the carbonyl value in frying oils based on LF-NMR combined with chemometrics

Low-field nuclear magnetic resonance (LF-NMR) combined with chemometrics was used for the rapidly and nondestructively quantitative determination of carbonyl value (CV) of frying oils during frying process. The quality indices of frying oils during frying process were analyzed as well as the changes of its LF-NMR signal, followed by exploring the correlation between the quality indices of frying oils and the relaxation-characteristic indices and investigating the influences of modeling data and preprocessing methods on the modeling performance. Based on the echo decay curves data of LF-NMR and the relaxation-characteristic indices data, the prediction model of CV was established by partial least square (PLS), principal component regression (PCR), multiple linear regression (MLR), and support vector machine regression (SVR). Results showed that there was a significant correlation between CV and relaxation-characteristic indices (p < 0.01) with both modeling data and preprocessing methods affecting the model performance. The prediction performance of non-linear SVR model was significantly superior to that of linear modeling methods (PLS, PCR, and MLR). The best prediction model of CV was built using the SVR method based on echo decay curves data. The root mean square error of prediction and coefficient of determination were 2.599 mmol/kg and 0.9873, respectively.

On-site preparation of sandwich plasmonic coupled SERS tape toward pesticide residue determination on food surface.

Asandwich plasmonic coupled surface enhanced Raman spectroscopy (SERS) tape is proposedprepared by peeling the chemical printed silver nanocorals (AgNCs) from Cu sheet with adhesive tape, which can sample targets from food surface and sandwich them between substrates and Cu sheet for SERS detection. The solid-to-solid transformation method for fabricating SERS tapes can effectively avoid the weakening of tape stickiness during the preparation process. The sandwich plasmonic coupled structure of AgNC substrate, targets, and Cu sheet display excellent SERS activity (EF = 1.62 × 107) for sensitive determination of analytes. In addition, due to the high heat conductivity of Cu sheet, the thermal effect of laser irradiation during SERS detection cannot damage the AgNC tapes, which ensures the reproducibility of subsequent quantification. The sandwich plasmonic coupled SERS tape is demonstrated to quantify malachite green (MG) and methyl parathion (MP) with good linear coefficients (> 0.98) by two typical calibration plots under different concentration ranges. The limit of detection (LOD) of the method is 0.17 ng/cm2 and 0.48 μg/cm2 (S/N = 3) for MG and MP. This method can realize the quantitative determination of MP and MG on the surface of fruits and fish scale with recoveries of 93-113%. The satisfactory detection results demonstrate the proposed sandwich plasmonic coupled AgNC tape can be successfully applied toSERS-based point-of-care testing (POCT) for pesticide residue determination, which will provide a new path for designing and constructing SERS tapes.

EXPERIMENTAL DETERMINATION OF ADDING CELLULOSE NITRATE TO THE OCTANIC NUMBER OF FUELS

The paperwork has as purpose improvement of anti-explosive properties of liquid fuels for spark ignition engines through nitrate addition and quantitative determination of the octane number resulting from the CFR ASTM Waukesha engine support.

[18F]2-fluoro-2-deoxy-sorbitol ([18F]FDS) PET imaging repurposed for quantitative estimation of blood-brain barrier permeability in a rat model of Alzheimer's disease

Numerous studies suggest that blood-brain barrier (BBB) dysfunction may contribute to the progression of Alzheimer's disease (AD). Clinically available neuroimaging methods are needed for quantitative "scoring" of BBB permeability in AD patients. [18F]2-fluoro-2-deoxy-sorbitol ([18F]FDS), which can be easily obtained from simple chemical reduction of commercial [18F]2-fluoro-2-deoxy-glucose ([18F]FDG), was investigated as a small-molecule marker of BBB permeability, in a pre-clinical model of AD using in vivo PET imaging. Chemical reduction of [18F]FDG to [18F]FDS was obtained with a 100% conversion yield. Dynamic PET acquisitions were performed in the APP/PS1 rat model of AD (TgF344-AD, n=3) compared with age-matched littermates (WT, n=4). The brain uptake of [18F]FDS was determined in selected brain regions, delineated from a coregistered rat brain template. The brain uptake of [18F]FDS in the brain regions of AD rats versus WT rats was compared using a 2-way ANOVA. The uptake of [18F]FDS was significantly higher in the whole brain of AD rats, as compared with WT rats (P<0.001), suggesting increased BBB permeability. Enhanced brain uptake of [18F]FDS in AD rats was significantly different across brain regions (P<0.001). Minimum difference was observed in the amygdala (+89.0±7.6%, P<0.001) and maximum difference was observed in the midbrain (+177.8±29.2%, P<0.001). [18F]FDS, initially proposed as radio-pharmaceutical to estimate renal filtration using PET imaging, can be repurposed for non-invasive and quantitative determination of BBB permeability in vivo. Making the best with the quantitative properties of PET imaging, it was possible to estimate the extent of enhanced BBB permeability in a rat model of AD.

Hydroxylamine enhanced Fe3O4/H2O2 system for removing tartrazine

In recent years, dye wastewater caused serious effects on environmental ecology and human health. Thus, in the present study, hydroxylamine (HA) was used to improve the Fe3O4/H2O2 process for removing the typical dye pollutant (tartrazine). Only 2.8% tartrazine could be removed in Fe3O4/H2O2 system within 60 min at the reaction of 1 g/L Fe3O4, 1 mM H2O2, and pH 4 while 97.5% tartrazine could be removed within 20 min after adding 1 mM HA into the Fe3O4/H2O2 system. Compared with Fe3O4/H2O2 system, the removal rate for removing tartrazine in Fe3O4-HA/H2O2 system could enhance more than 100 times. Electron paramagnetic resonance tests (EPR), radical quenching experiments and quantitative determination demonstrated that •OH was the major reactive species for removing tartrazine in Fe3O4-HA/H2O2 system and •OH produced concentration in Fe3O4-HA/H2O2 system was also much higher than that in Fe3O4/H2O2 system. The key factors affecting tartrazine removal in Fe3O4-HA/H2O2 system were also conducted. The optimal HA dosage, Fe3O4 dosage, and H2O2 dosage was 1 mM, 1 g/L and 1 mM. The optimal initial pH in Fe3O4-HA/H2O2 system was 3, but compared with Fe3O4/H2O2 system, the tatrazine removal efficiency could significantly improve under any initial pH condition. Fe3O4-HA/H2O2 process had strong adaptability to inorganic ions and good applicability to different pollutants. Fe3O4-HA/H2O2 process also exhibited good recycle ability for tartrazine removal. Overall, Fe3O4-HA/H2O2 process is an effective and good practical applicability approach for dye wastewater treatment.

UHPLC-MS/MS Technique: Applications in Analytical Chemistry

The ultra-high performance liquid chromatography-mass spectrometry/mass spectrometry (UHPLC-MS/MS) is becoming most advanced technique used for analysis of wide range of compounds in analytical chemistry. This technique has been effectively utilized for identifying and quantitatively determining substances in several pharmaceutical analysis fields. The UHPLC technique offers superior sensitivity, selectivity and peak shape in comparison to the conventional HPLC technique. The UHPLC coupled with various mass spectrometers gives accurate mass fragmentations which is ultimately helpful in structural identification and quantitative determination of compounds. The review provides brief introduction on development of UHPLC column packing materials and coupled mass detectors such as single quadrupole, triple quadrupole and time-of-flight mass. This review article also summarizes application of UHPLC-MS/MS technique in various fields of analytical chemistry.