Quantification Of Acids Research Articles

The Quantitation of EPA and DHA in Fish Oil Dietary Supplements Sold in the United States

The dietary supplement industry is expanding, but it still remains far less regulated than the pharmaceutical industry, resulting in inconsistent quality control. Limited research has been performed in the U.S., particularly regarding the quantification of omega-3 fatty acids like eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The aim of this study was to quantify the omega-3 fatty acid content in fish oil capsules and liquids purchased from major stores and a grocery chain and compare the results to their label claims. A total of 6 out of 15 were found to have EPA levels ±20% and 10 out of 15 were ±20% outside of the label claim for DHA. One product did not have a label claim for EPA and DHA, but did have a claim for total omega-3 content. These discrepancies indicate that consumers may unwittingly be consuming higher or lower quantities of omega-3 fatty acids than expected, potentially affecting their health outcomes.

A Simple, Cost-Effective, and Sustainable Method for Extraction and Quantification of Chebulagic Acid from Terminalia bellirica (Gaertn.) Roxb. Using RP-HPLC: A Comparative Study

Chebulagic acid (CA), a hydrolysable tannin found in Terminalia bellirica (T. bellirica) (Gaertn.) Roxb., has gained prominence as a significant component in Ayurvedic medicine. This study optimized methods for determining CA in T. bellirica, focusing on fruit samples and prioritizing simplicity, cost-effectiveness, less time duration, and sustainability. We evaluated various extraction techniques, including continuous shaking, microwave assisted extraction, and Soxhlet extraction using green solvents. Quantification of CA was conducted using Reverse Phase High-Performance Liquid Chromatography (RP-HPLC), with confirmation achieved via UV-Visible (UV-Vis) spectroscopy, Thin Layer Chromatography (TLC), and Liquid Chromatography-High Resolution Mass Spectrometry (LC-HRMS). Results indicated that Soxhlet and microwave significant extraction methods, particularly with ethanol as the green solvent. Soxhlet extraction yielded 49607.73±18.82 μg/mL for fresh fruit and 42952.53±19.09 μg/mL for dry fruit, while microwave extraction resulted in 43627.56±113.48 μg/mL for fresh fruit and 40466.33±130.90 μg/mL for dry fruit respectively. These findings conclude that ethanol as a green solvent in Soxhlet or microwave assisted extraction emerge as most efficient, straightforward, and effective approach for detecting and screening CA in T. bellirica samples.

Metabonomic and transcriptomic profiling reveals amino acid metabolism affects the quality of premium japonica rice varieties in Northeast China

Rice consumption and demand for premium rice are increasing worldwide. However, the characterizations and how to identify the premium rice are still unclear. Small molecular metabolites have a great advantage in distinguishing subtle differences among similar agricultural products. So, we hypothesized that the metabolites would be the key to identifying the tiny differences in premium rice among similar varieties. In this study, we performed metabolomic and transcriptomic profiles to comprehensively elucidate key metabolites, genes, and formation mechanisms of premium rice. As a result, eight compounds belong to four categories, and 49 different expressional genes were identified in premium rice varieties after comparing with the second-best varieties. Moreover, the integrated analysis confirmed that the amino acid pathway, including 42 expression genes and 11 metabolites, was critical for the premium rice formation. Six genes and two metabolites had significant regulatory effects on the pathways. Furthermore, amino acid quantification confirmed the content of 12 kinds of hydrolytic amino acids, such as aspartic acid and arginine were different between premium and other varieties. These amino acids may serve as potential biomarkers for differentiating premium rice in Northeast China. Our results strongly support the possibility of differentiating premium rice and would provide essential data for premium rice identification and metabolomics-assisted breeding.

A biochemical mini-research project: Can yeast fermentation decrease the amount of phytic acid in soybeans?

This mini-research project studied the effect of yeast fermentation on the nutritional value of soybeans, specifically the concentration of phytic acid, protein, and lipids. With prior experience in protein and lipids analysis, the students (n = 12) in this laboratory applied their critical thinking and problem-solving skills to design and conduct their own assays for phytic acid extraction and quantification. All students decided to use ion exchange chromatography to extract phytic acid and UV/vis spectroscopy with Wade’s reagent for phytic acid quantification. These methods were evaluated by the students as simple and effective in analyzing phytic acid from soybeans. This project allowed students to use several of the methods used in other parts of the semester in addition to adding new methods to evaluate a research question.

Low-Cost Electrochemical Determination of L-Ascorbic Acid Using Screen-Printed Electrodes and Development of an Electronic Tongue for Juice Analysis

Low-cost electrochemical methodologies for the determination of L-ascorbic acid (vitamin C) and the analysis of juices are developed based on its electro-oxidation on carbon screen-printed electrodes. A novel chronoamperometric methodology is developed for the quantification of L-ascorbic acid in fruit juices. The proposed method stands out for its simplicity and rapidity, demonstrating its efficacy in determining L-ascorbic acid content in various fruit juices. Notably, the results obtained with this chronoamperometric approach are compared with those yielded by chromatography, with no significant differences between the two methods being found. Additionally, an electronic tongue is developed for the differentiation of juices based on the square wave voltammetric signals.

Detection of "smoke powder" etomidate and its metabolite etomidate acid in blood and urine by UHPLC-MS-MS: application in authentic cases.

Recently, etomidate has been widely used as an alternative in illicit drug market. It is usually added to regular cigarette tobacco (commonly known as "cigarette powder") or mixed in e-cigarette oil sold through the Internet, retail stores, or entertainment outlets and other channels. An ultra-high performance liquid chromatography tandem mass spectrometry method was developed to quantify etomidate and etomidate acid in human blood and urine. The limit of detection (LOD) of etomidate and etomidate acid in blood is 0.5 and 2 ng/mL, respectively, and the lower limit of quantification (LLOQ) is 1 and 5 ng/mL, respectively. The LOD of etomidate and etomidate acid in urine is 1 and 2 ng/mL, respectively, and the LLOQ is 2 and 5 ng/mL, respectively. The precision, accuracy, recoveries, and matrix effects of etomidate and etomidate acid determinations in blood and urine met the requirements for methodological validation. The method was successfully applied to the identification and quantification of etomidate and etomidate acid in blood and urine of 62 forensic cases. The concentration of etomidate ranged from 1.52 to 8.41 ng/mL (positive cases, n = 5) and the concentration of etomidate acid ranged from 2.76 to 112 ng/mL (positive cases, n = 5) in blood. The concentrations of etomidate and etomidate acid in urine samples were 2.64-79,300 ng/mL (positive cases, n = 59) and 6.11-518,000 ng/mL (positive cases, n = 60), respectively. Therefore, the concentration of etomidate in blood and urine is mostly higher than that of etomidate.

Dehydroascorbic acid quantification in human plasma: Simultaneous direct measurement of the ascorbic acid/dehydroascorbic acid couple by UPLC/MS-MS

Ascorbic acid (AA, vitamin C) and dehydroascorbic acid (DHA) constitute a biological couple. No technique can accurately, independently, and simultaneously quantify both members of the couple in animal and human samples, thereby constraining advances in physiology and pathophysiology. Here we describe a new UPLC/MS/MS method to measure both compounds directly and independently in human plasma. Lower limits of quantification were 16 nM, with linear coefficients >0.99 over a 100-fold concentration range. The method was stable and reproducible with <10 % injection-to-injection variation. Use of isotopic labeled internal standards for both compounds ensured precision and accuracy. Plasma preparation required only 2 steps. In plasma samples from 14 anonymized subjects who met criteria for blood donation, mean concentrations were 6±2 μmol/L (mean ± SD) and 56 ± 14 μmol/L for DHA and AA respectively, with (DHA)/(AA + DHA) ratio of 9.8 %. This method represents a pioneering approach to measuring the AA/DHA couple in human plasma.

Advancements in ascorbic acid quantification: from macroscopic analysis to miniaturized nano-sensing for quality control in food and beverage

Abstract Ascorbic acid (AA) or vitamin C, is vital in food safety, pharmaceutical and biomedical industries. This review discusses recent advancements in biosensors for AA detection. Traditional macro-analysis techniques such as high-performance liquids chromatography (HPLC), and flow injection analysis (FIA) provide accurate measurements but are costly and require specialized handling. Miniaturized nano-sensors are emerging as promising alternatives, offering advantages such as portability, cost effectiveness, and rapid response. This review explores the working principles of these nano-sensors, highlighting colorimetric, fluorometric and electrochemical detection methods. It also outlines the current AA biosensing landscape, detailing strategies to improve selectivity and specificity, including the choice of biorecognition elements and material selection for detection probe synthesis. Emerging nanomaterials and their applicability to support sensing activity are explored. This review serves as a valuable resource, suggesting future research directions to address existing challenges and further advance biosensor technology.

Loureirin B Ameliorates Glycolipid Metabolism Disorders in Ob/ob Mice by Regulating Bile Acid Levels and Modulating Gut Microbiota Composition.

Loureirin B (LB), an active component of Resina Draconis, exhibits hypoglycemic and hypolipidemic effects; however, its mode of action remains unclear. Here, ob/ob mice were utilized to investigate the effects of LB on the regulation of glucolipid metabolism disorders. Non-targeted metabolomics and 16S rDNA sequencing were performed to elucidate the potential mechanisms involved. Results indicated that LB treatment (45 mg/kg) significantly improved glucose intolerance and insulin resistance, reduced lipid levels, and alleviated hepatic steatosis. Non-targeted metabolomics analysis revealed that LB treatment regulated bile acid levels. Quantification of liver bile acids demonstrated that LB treatment significantly decreased the ratio of 12α-OH to non-12α-OH bile acids in the liver. 16S rDNA sequencing results showed that LB treatment increased the abundance of short-chain fatty acid-producing microbiota while decreasing the abundance of bile salt hydrolase (BSH) enzyme-producing microbiota. In conclusion, LB ameliorates glucolipid metabolism disorders by regulating liver bile acid levels and modulating the composition of the gut microbiota.

Fast spectroscopic and multisensor methods for analysis of glucosamine and hyaluronic acid in dietary supplements

There is a lack of fast and inexpensive analytical methods for quantification of key ingredients in dietary supplements. Here we explore the potential of near infrared (NIR) spectrometry, attenuated total reflection infrared (ATR-IR) spectrometry and potentiometric multisensor system (MSS) in quantitative determination of glucosamine and hyaluronic acid in commercial samples of dietary supplements. All three methods have demonstrated their applicability for this task when combined with chemometric data processing. Principal Component Analysis (PCA) revealed similarities across the three techniques, indicating the presence of distinct sample composition. Partial least squares (PLS) models were constructed for glucosamine and hyaluronic acid quantification. The root mean square error of cross validation (RMSECV) for glucosamine quantification varied between 7.7 wt% and 8.9 wt%. NIR spectrometry has demonstrated the best accuracy for hyaluronic acid (RMSECV = 9.9 wt%), while ATR-IR and MSS yielded somewhat worse performance with RMSECV values of 12.1 and 11.3 wt%, respectively. The findings of this study indicated that NIR, ATR-IR and MSS exhibit reduced accuracy in comparison to complex and high-precision analytical techniques. However, they can be employed for the rapid, semi-quantitative evaluation of glucosamine and hyaluronic acid in dietary supplements, with the possibility of integration into routine quality control procedures.

LAMP-MS for Locus-Specific Visual Quantification of DNA 5mC and RNA m6A Using Ultra-Low Input.

Enhancing the effectiveness of utilizing circulating cell-free DNA (cfDNA) for disease screening remains a challenge, necessitating improved sensitivity, specificity, cost-efficiency, and patient adherence. We present here LAMP-MS, an innovative technology that integrates linear amplification with single-base quantitative nucleic acid mass spectrometry on silicon chips. This approach overcomes several limitations in utilizing cfDNA 5-methylcytosine (5mC) status for colorectal cancer (CRC) screening. LAMP-MS enables unbiased amplification of as little as 1 ng of cfDNA, site-specifically quantify methylation levels of tens to hundreds of 5mC sites, thereby facilitating cost-effective, high-resolution quantitative detection of cfDNA methylation markers. We have validated the accuracy of DNA methylation determination using DNA probes and cfDNA from patient plasma samples, confirmed by mass spectrometric peak areas. Additionally, we have further shown this Mass Array technology could be expanded to also quantify RNA m6A modification sites. Combining the ability to work with ultra-low input materials and a visually interpretable output, LAMP-MS stands out as a promising method for real-world applications in clinics and laboratories for nucleic acid methylation detection and quantification.

LAMP‐MS for Locus‐Specific Visual Quantification of DNA 5mC and RNA m6A Using Ultra‐Low Input

Enhancing the effectiveness of utilizing circulating cell‐free DNA (cfDNA) for disease screening remains a challenge, necessitating improved sensitivity, specificity, cost‐efficiency, and patient adherence. We present here LAMP‐MS, an innovative technology that integrates linear amplification with single‐base quantitative nucleic acid mass spectrometry on silicon chips. This approach overcomes several limitations in utilizing cfDNA 5‐methylcytosine (5mC) status for colorectal cancer (CRC) screening. LAMP‐MS enables unbiased amplification of as little as 1 ng of cfDNA, site‐specifically quantify methylation levels of tens to hundreds of 5mC sites, thereby facilitating cost‐effective, high‐resolution quantitative detection of cfDNA methylation markers. We have validated the accuracy of DNA methylation determination using DNA probes and cfDNA from patient plasma samples, confirmed by mass spectrometric peak areas. Additionally, we have further shown this Mass Array technology could be expanded to also quantify RNA m6A modification sites. Combining the ability to work with ultra‐low input materials and a visually interpretable output, LAMP‐MS stands out as a promising method for real‐world applications in clinics and laboratories for nucleic acid methylation detection and quantification.

Metal–Organic Framework-Derived CeO2/Gold Nanospheres in a Highly Sensitive Electrochemical Sensor for Uric Acid Quantification in Milk

In this work, CeBTC (a cerium(III) 1,3,5-benzene-tricarboxylate), was used as a precursor for obtaining CeO2 nanoparticles (nanoceria) with better sensor performances than CeO2 nanoparticles synthesized by the solvothermal method. Metal–organic framework-derived nanoceria (MOFdNC) were functionalized with spheric gold nanoparticles (AuNPs) to further improve non-enzymatic electrode material for highly sensitive detection of prominent biocompound uric acid (UA) at this modified carbon paste electrode (MOFdNC/AuNPs&amp;CPE). X-ray powder diffraction (XRPD) and transmission electron microscopy (TEM) analysis were used for morphological structure characterization of the obtained nanostructures. Cyclic voltammetry and electrochemical impedance spectroscopy, both in an [Fe(CN)6]3−/4− redox system and uric acid standard solutions, were used for the characterization of material electrocatalytic performances, the selection of optimal electrode modifier, and the estimation of nature and kinetic parameters of the electrode process. Square-wave voltammetry (SWV) was chosen, and the optimal parameters of technique and experimental conditions were established for determining uric acid over MOFdNC/AuNPs&amp;CPE. Together with the development of the sensor, the detection procedure was optimized with the following analytical parameters: linear operating ranges of 0.05 to 1 µM and 1 to 50 µM and a detection limit of 0.011 µM, with outstanding repeatability, reproducibility, and stability of the sensor surface. Anti-interference experiments yielded a stable and nearly unchanged current response with negligible or no change in peak potential. After minor sample pretreatment, the proposed electrode was successfully applied for the quantification of UA in milk.

Carbohydrate-binding module could integrate with ELISA and serve the simple and specific quantification of hyaluronic acid

Quantification is essential in the research and development of polysaccharides. However, achieving simplicity and specificity in polysaccharide quantification remains a challenging task. Enzyme-linked immunosorbent assay (ELISA) based on antibodies provides a straightforward and specific quantification strategy. Nevertheless, acquiring antibodies for polysaccharides is complicated. Carbohydrate-binding modules (CBMs), which can be efficiently obtained, exhibit the capability to specifically recognize and bind carbohydrates. In this study, we verified the feasibility of a CBM-based ELISA for the quantification of hyaluronic acid (HA) by replacing an antibody with a CBM. The CBM-based ELISA, which employed a HA-specific CBM, exhibited a linear detection range spanning from 10 to 100 μg/mL. Both intra-assay and inter-assay coefficients of variation remained below 15 % and recoveries ranged from 96.26 % to 98.22 %, indicating favorable precision and accuracy. The method exhibited specificity exclusively to HA, suggesting its reliance on CBM binding specificity. The effectiveness of the method in analyzing commercial products was confirmed. Additionally, a comparison with the carbazole assay revealed a highly significant correlation (r = 0.994). By integrating CBMs with ELISA, the study presented a novel and easily implementable solution for simple and specific quantification of HA.

A comparative study of chemical composition, the level of fatty acids, amino acids and mineral elements between two types of catfish (Bagrus and Muraena) found in the upper Tigris River

Fish meat is considered the second most interesting to consume in Iraq hence, consumers always consider the sensory and nutritional profile of the fish meat. The study aimed to investigate the chemical composition and level of fatty acids and amino acids in Bagrus and Muraena fish fillets. These fish for this study were obtained from the upper Tigris river in the Tikrit region of Iraq, as the demand for these types of fish increased in recent years. In this work, High Performance Liquid Chromatography −UV (HPLC-UV) was used for quantification of amino acids, and atomic absorption was used for quantifying the elements. The extraction was performed by liquid –liquid extraction and purified by dispersive phase purification. Results showed that the moisture percentages in Bagrus meat were 71.36 %, while Muraena meat recorded as 71.10 %. Moreover, the protein percentages for both fish types were found as 21.36 and 21.43 % respectively. Lipid percentages in fillets of Bagrus and Muraena were 3.59 and 4.62 %, respectively. The proportion of ash was 3.01 % in Bagrus meat, while it was 2.55 % in Muraena meat. The results also presented that the Muraena has a significantly higher saturated fatty acid level (26.06 %), whereas in Bagrus meat was much less (16.6 %). The highest percentage of amino acids in Bagrus meat recorded (92.66 %), while it was 61.94 % in Muraena meat. The Bagrus meat contained essential amino acids with a higher percentage (54.04 %), compared to Muraena meat (28.55 %), non-essential Amino acids percentage also reached 47.56 % in Bagrus fish fillets. The amino acids like alanine had recorded the highest percentage among non-essential amino acids, as its level resulted in 38.62 %, while the level (33.39 %) was lower in Muraena meat.

Development and application of an LC-MS/MS method for the combined quantification of oxysterols and bile acids

Oxysterols and bile acids are interconnected bioactive lipids playing pivotal roles in diverse physiological and pathological processes. For this reason, they are increasingly studied together for their implications in various diseases. However, due to analytical challenges inherent to the nature of these analytes, very few methods have been developed for the simultaneous analysis of these lipids. We here report the development of a sensitive LC-MS/MS method for the combined quantification of 18 oxysterols, 11 unconjugated, 15 conjugated bile acids, and 1 bile acid precursor, using 8 isotope-labeled internal standards, addressing the need for a more comprehensive analysis of these interesting lipid families. During the method development, we investigated different extraction protocols, set up a purification step, and achieved chromatographic separation for these lipids, overcoming challenges such as the large number of analytes, isomers, and wide range of polarity across the analytes. Finally, the method was successfully applied to the analysis of preclinical and clinical samples, quantifying 12 oxysterols and 14 bile acids in human plasma, 10 oxysterols and 18 bile acids in mouse plasma from the vena cava, and 10 oxysterols and 20 bile acids in mouse plasma from the portal vein within a single chromatographic run.

Peroxidase-like CuS nanozyme-based sensor array for the quantification and discrimination of ascorbic acid

Peroxidase-like CuS nanozyme-based sensor array for the quantification and discrimination of ascorbic acid

Remote Sensing of Nitric Acid and Temperature via Design of Experiments, Chemometrics, and Raman Spectroscopy.

This study presents an effective method for the quantification of nitric acid (0.1-9 M) and the temperature (20-60 °C) through optimal experimental design, chemometrics, and Raman spectroscopy. Raman spectroscopy can be deployed using fiber-optic cables in hot cell environments to support processing operations in the nuclear field and industry. Chemical operations frequently use nitric acid and operate at nonambient temperatures either by design or by circumstance. Examples of Raman spectroscopy for the quantification of nitric acid with applications in the industrial field are profuse. However, the effect of temperature on quantification is often ignored and should be considered in real-world scenarios. Statistical design of experiments was used to build training sets for partial least-squares regression and support vector regression (SVR) models. The SVR model with a nonlinear kernel outperformed the top partial least-squares models with respect to temperature and resulted in percent root-mean-square error of prediction of 1.8% and 2.3% for nitric acid and temperature, respectively. The D-optimal design strategy decreased the sampling time by 75% compared to a more traditional seven-level full factorial option. The new method advances chemometric applications within and beyond the nuclear field and industry.

A Benchmark Study of DFT-Computed p-Block Element Lewis Pair Formation Enthalpies against Experimental Calorimetric Data.

The quantification of Lewis acidity is of fundamental and applied importance in chemistry. While the computed fluoride ion affinity (FIA) is the most widely accepted thermodynamic metric, only sparse experimental values exist. Accordingly, a benchmark of methods for computing Lewis pair formation enthalpies, also with a broader set of Lewis bases against experimental data, is missing. Herein, we evaluate different density functionals against a set of 112 experimentally determined Lewis acid/base binding enthalpies and gauge influences such as solvation correction in structure optimization. From that, we can recommend r2SCAN-3c for robust quantification of this omnipresent interaction.

Simultaneous quantification of chlorogenic acid, quercetin, and kaempferol in Urceola rosea leaves by CE and HPLC techniques: method validation and comparative study

Two analytical methods, CE and HPLC, were developed, validated, and compared for simultaneously determining chlorogenic acid, quercetin, and kaempferol in Urceola rosea leaves collected from twelve different sources of Thailand. The determination was accomplished by CE on the uncoated fused silica capillary tube and by HPLC on the ZORBAX Eclipse Plus C18 column. Chlorogenic acid was found to have the highest average amount in U. rosea leaves, followed by kaempferol and quercetin, respectively. Compared to CE, HPLC is considered to provide higher sensitivity and robustness as indicated by lower LOD and LOQ values as well as % RSD of robustness for all analytes. Overall, the present study first demonstrated that both methods were selective, sensitive, and robust, allowing reliable simultaneous quantification of three major bioactive compounds in U. rosea leaves, which could be beneficially applied for quality control assessment of this plant material, particularly those cultivated in Thailand.