Limit Of Quantitation Research Articles

Enhanced Electrochemical Performance of Copper(II) Metal Organic Framework‐Ternary Quantum Dots Composite towards the Detection of Bisphenol A

AbstractTernary quantum dot metal organic framework (MOFs) composite sensor formulated as (ZnInSe2@[Cu(2‐HNA)2(H2O)]) with an enhanced electrochemical performance was synthesized from a copper(II) metal‐organic framework complex ([Cu(2‐HNA)2(H2O)]) and ZnInSe2 ternary quantum dot (TQDs). The compounds were characterized by Fourier transform infrared spectroscopy, Ultraviolet‐Visible spectroscopy, transmission electron microscopy, scanning electron microscopy, single crystal X‐ray crystallography, and photoluminescence. Molecular structure of the copper(II) complex revealed a distorted square pyramidal geometry with two molecules of 2‐hydroxy‐1‐naphthaldedyde at the basal planes as bidentate chelating ligands with a coordinated water molecule at the apical position. TEM micrographs revealed monodispersed composite with an average particle size of 3.2 nm. The composite and its precursors were used as ectrochemical sensor for the detection of bisphenol A, using cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy. The composite modified on a gold electrode exhibited enhanced electrochemical performance in comparison to those of the MOFs and TQDs. The reaction process at the surface of the modified electrode with the composite is diffusion controlled with a limit of detection, and limit of quantitation of 4.70 nM and 14.26 nM over a concentration range of 10–50 nM (S/N=3). The gold modified composite electrode is stable and could serve as a model for the development of electrochemical sensor to determine BPA.

Development of an Indirect Competitive ELISA Based on a Stable Epitope of β-Lactoglobulin for Its Detection in Hydrolyzed Formula Milk Powder

The target of traditional immunological detection methods for milk allergens is usually the whole β-lactoglobulin molecule. However, thermal processes and hydrolysis can destroy the epitope of β-lactoglobulin and interfere with its accurate detection and labeling in prepackaged foods, posing a health risk to milk-allergic patients. There currently remains a need to excavate and locate recognition sites for β-lactoglobulin in thermally processed and hydrolyzed products. Therefore, a stable epitope of β-lactoglobulin (CAQKKIIAEKTKIPAVFKIDA) was selected as the ideal recognition site, and an indirect competitive enzyme-linked immunosorbent assay (ELISA) was developed using an antibody against this stable β-lactoglobulin epitope in order to improve the detection of β-lactoglobulin in thermally processed and hydrolyzed foods in this study. The stable epitope of β-lactoglobulin was selected using a molecular dynamics simulation, and the binding ability of anti-stable epitope antibodies was characterized using indirect ELISA and indirect competitive ELISA. The limit of detection (LOD) and limit of quantitation (LOQ) of the established ELISA were 0.25 and 1.07 mg·kg−1, respectively. Furthermore, the developed ELISA only showed cross-reactivity to goat milk among 23 common foods, therefore exhibiting high specificity to bovine β-lactoglobulin. In addition, the developed ELISA was able to effectively detect β-lactoglobulin residue in processed commercial foods and hydrolyzed formula milk powder. Our findings provide a novel strategy for accurately detecting milk allergens based on stable epitope recognition in thermally processed and hydrolyzed foods.

Quantitative estimation and validation of Alectinib hydrochloride drug substance using quantitative nuclear magnetic resonance spectroscopy

Nuclear magnetic resonance spectroscopy has been recently used for quantitative estimation of drug substance which has numerous merits in pharmaceutical applications when compared to traditional methods of chromatography. Present study focuses on method development and validation of quantitative proton nuclear magnetic spectroscopy method for estimation of alectinib hydrochloride drug substance. This method involves use of internal standard in presence of alectinib hydrochloride. For quantitation, 1H NMR signals at 8.4 ppm and 6.7 ppm corresponding to analyte proton of alectinib and ethyl 4-(dimethyl amino) benzoate internal standard respectively were used. Moreover, this method was validated as per ICH guidelines for accuracy, precision, linearity, limit of detection, limit of quantitation, range and robustness. Assay estimation by Q-NMR is facile and time-efficient which does not require reference standard of analyte and yet accurate and precise alternative as compared to estimation by other chromatographic techniques.

Hybrid Quadrupole Mass Filter-Radial Ejection Linear Ion Trap and Intelligent Data Acquisition Enable Highly Multiplex Targeted Proteomics.

Targeted mass spectrometry (MS) methods are powerful tools for the selective and sensitive analysis of peptides identified in global discovery experiments. Selected reaction monitoring (SRM) is the most widely accepted clinical MS method due to its reliability and performance. However, SRM and parallel reaction monitoring (PRM) are limited in throughput and are typically used for assays with around 100 targets or fewer. Here we introduce a new MS platform featuring a quadrupole mass filter, collision cell, and linear ion trap architecture, capable of targeting 5000-8000 peptides per hour. This high multiplexing capability is facilitated by acquisition rates of 70-100 Hz and real-time chromatogram alignment. We present a Skyline external software tool for building targeted methods based on data-independent acquisition chromatogram libraries or unscheduled analysis of heavy labeled standards. Our platform demonstrates ∼10× lower limits of quantitation (LOQs) than traditional SRM on a triple quadrupole instrument for highly multiplexed assays, due to parallel product ion accumulation. Finally, we explore how analytical figures of merit vary with method duration and the number of analytes, providing insights into optimizing assay performance.

Development and characterization of high-throughput serological assays to measure magnitude and functional immune response against S. Paratyphi A in human samples

Typhoid and Paratyphoid fever cause a global health burden, especially for the children of Southern Asia. The impact of the disease is further exacerbated by the dramatic increase of antimicrobial resistance. While vaccines against Salmonella Typhi have been developed and successfully introduced, an effective vaccine targeting S. Paratyphi A is still lacking. Several efforts are currently ongoing to develop vaccines targeting both S. Typhi and S. Paratyphi A. In order to analyze the immune response induced by vaccination and in sero-epidemiological studies, easy to perform and high throughput immunoassays are needed. Here we present the setup and characterization of a customized ELISA assay and of a luminescent-based serum bactericidal assay (L-SBA) to measure the quantity of S. Paratyphi O antigen specific antibodies and their functional activity against S. Paratyphi A. Robust quality control criteria have been put in place both for ELISA and SBA and assays have been fully characterized in terms of quantitation limit, limit of blanks, specificity, linearity and precision. Assays are being employed to analyze samples from clinical trials, enabling the assessment of immunogenicity during clinical vaccine development.

Pressurized liquid extraction of sulfite for quantitation by capillary zone electrophoresis.

Sulfite is an additive used in shrimp processing to prevent discoloration. However, sulfite can cause health issues for sensitive consumers, making its monitoring necessary. Determining sulfite concentrations is complex because the Monier-Williams reference method is laborious and has low analytical throughput. Additionally, new techniques are needed to stabilize sulfite during the extraction process because this analyte undergoes rapid oxidation. A new method involving extraction and derivatization of sulfite with formaldehyde through automated pressurized liquid extraction (PLE), followed by quantitation by capillary zone electrophoresis with diode-array detector in indirect mode, was developed and optimized using multivariate planning. The PLE procedure was compared to another solid-liquid extraction method. The new method successfully stabilized and extracted sulfite from shrimp in few steps with adequate precision (CV<3.8%), producing extracts that were stable for 10 days. Recovery was satisfactory (97%-99%), and the limits of detection (4.6mgkg-1) and quantitation (15.4mgkg-1) were suitable for the intended purpose.

Ion-chromatographic determination of common anions in drinking water in some regions of the Republic of Armenia

The present study investigated the anion composition of drinking water from various cities and villages in Armenia, including spring water and tap water samples. The simultaneous separation was achieved for fluoride, chloride, bromide, nitrite, nitrate, sulfate, and phosphate anions with the correlation coefficients &amp;gt;0.998. Validation of the method was carried out in accordance with the requirements of guidelines in terms of selectivity, specificity, system suitability, linearity, accuracy, precision, lower limits of detection and quantitation, robustness, and stability. The method was suitable for routine drinking water quality assessment in line with the national or World Health Organization (WHO) regulations. The validated method was further used to analyze drinking water samples from different regions of Armenia. The observed concentrations for the anions in drinking water complied with the WHO limits for drinking water with some exceptions. The test method can be submitted to quality control laboratories as a convenient and practical tool for routine analysis and monitoring studies.

Sensitive Determination of Diosmetin Using Orange‐Red Fluorescent Copper Nanoclusters

AbstractDiosmetin (Dio) has attracted much attention because of its good pharmacological effects, thus it is necessary to determine its content in scientific research and production. In the study, stable orange‐red copper nanoclusters with 4‐hydroxy‐2‐mercapto‐6‐propylpyrimidine (PTU) as reducing agent and ligand (PTU‐CuNCs) was prepared by a simple approach with superior quantum yield (18.03 %), and the PTU‐CuNCs with red fluorescence could improve the anti‐interference ability of detection. Meanwhile, the synthesis conditions of PTU‐CuNCs were optimized and analyzed in detail. Through a series of experiments, it was found that inner filter effect (IFE) and dynamic quenching might become the main reasons for the fluorescence quenching of PTU‐CuNCs by Dio. Based on the mechanism, a fluorescence probe for the determination of Dio was established. In the range of 0.33–31.67 μmol L−1, the fluorescence quenching efficiency of PTU‐CuNCs was linearly related to the contents of Dio, and corresponding limit of determination (LOD) was estimated to be 101.3 nmol L−1, and limit of quantitation (LOQ) was calculated to be 337.4 nmol L−1. Furthermore, the method could be used effectively for the assay of Dio in practical samples.

A bioanalytically validated RP-HPLC method for simultaneous quantification of rivaroxaban, paracetamol, and ceftriaxone in human plasma: a combination used for COVID-19 management

Rivaroxaban is a direct oral anticoagulant medication that has been found to be beneficial for the management of thromboembolic events linked to the Corona virus disease 2019 (COVID-19) pandemic, which has resulted in more than 6 million deaths worldwide. Hence, a sensitive, selective, and green bioanalytically validated method was developed using RP-HPLC coupled with DAD for the simultaneous determination of rivaroxaban in human plasma, and two co-administered drugs, namely, paracetamol, an analgesic, and ceftriaxone, an antibiotic, that are used in the management of COVID-19. An Exsil 100 ODS C18 column (250 × 4.6 mm, 5 μm) was used as the stationary phase, and acetonitrile: water: methanol at a ratio of 60:30:10 (v/v/v) was used in isocratic mode as the mobile phase with a flow rate of 0.7 ml/min. The method was validated over a concentration range of 0.1–10.0 µg/mL for rivaroxaban, and 1.0–15.0 µg/mL for paracetamol and ceftriaxone. The lower limits of detection (LLODs) were found to be 0.03, 0.32, and 0.32 µg/ml for rivaroxaban, paracetamol, and ceftriaxone, respectively. Moreover, the lower limits of quantitation (LLOQs) were found to be 0.1, 0.96, and 0.98 µg/ml. The developed method showed excellent accuracy and precision for the determination of the aforementioned drugs. Four metrics were used to evaluate the greenness of the developed method. The results revealed that the suggested method is green, with values of 81 and 0.6 for the analytical eco-scale and analytical greenness assessment (AGREE), respectively.

Lateral Flow Immunoassay for the Rapid Detection of Thiamethoxam in Tea Based on a SERS Tag Constructed by Phenolic-Mediated Coating Engineering.

Sensitive and accurate detection of thiamethoxam in tea is significant to ensuring consumer health. In this study, surface-enhanced Raman scattering (SERS) tags were prepared by using a polyphenol-mediated coating engineering strategy. This approach involved the self-assembly of tannic acid (TA) and self-polymerization of benzene-1,4-dithiol (BDT) on the surface of gold nanoparticles, resulting in the formation of Au@pBDT-TA. The SERS tags possess high Raman signals and antibody adsorption properties, avoiding the complex decoration or label steps of SERS reporters. We discovered that Au@pBDT-TA, composed of gold nanoparticles at 40 nm and a pBDT-TA thickness of 10 nm, was optimal for the development of the SERS lateral flow immunoassay (LFIA). In comparison to the gold nanoparticle-based LFIA, the SERS-LFIA demonstrated 4-fold and 720-fold enhancements in visual and quantitative limits of detection in buffer solution. The SERS-LFIA demonstrated quantitative limits of detection of 0.06 and 0.1 ng/g for black and green tea, respectively, with a broader linear range spanning over 2 orders of magnitude and a short detection time of 20 min. The proposed SERS-LFIA not only offers a sensitive and reliable method for monitoring thiamethoxam in tea but also possesses a versatile potential that can be easily adapted for the trace detection of various other targets.

Developing a New Method for the Estimation of Valsartan (VST) in Pharmaceutical Dosage Samples by Using Diazotization and Coupling Reactions Spectrophotometrically

Introduction: A new method for valsartan (VST) estimation in pharmaceutical dosage samples by spectrophotometry was developed. Method: The method was based on the formation of coloured dye by the diazotization reaction of 3-amino-2-naphthol with sodium nitrite in an acidic medium to form diazonium compounds, which were then coupled with VST in a basic medium. Results: The drug sample showed linearity in the range 4.6 - 24.2 μgmL-1, and the λmax was found at 432nm. Sandell’s sensitivity (9.950×10-3), Molar absorbtivity (Ɛ= 4.377×104), regression equa-tion (y= 0.0775x + 0.0041), correlation coefficient (r2= 0.968), detection limit (DL= 0.668) and quantitation limit (QL= 2.024) were evaluated. Conclusion: The percentage recovery of the drug samples was found to be 100%. This method successfully determined VST in Pharmaceutical dosage samples.

Nanobody-Induced Aggregation of Gold Nanoparticles: A Mix-and-Read Strategy for the Rapid Detection of Cronobacter sakazakii.

Protein-nanoparticle interactions play a crucial role in both biomedical applications and the biosafety assessment of nanomaterials. Here, we found that nanobodies can induce citrate-capped gold nanoparticles (AuNPs) to aggregate into large clusters. Subsequently, we explored the mechanism behind this aggregation and proposed the "gold nucleation mechanism" to explain this phenomenon. Building on this observation, we developed a one-step label-free colorimetric method based on nanobody-induced AuNP aggregation. When nanobodies bind to target bacteria, spatial hindrance occurs, preventing further AuNPs aggregation. This alteration in surface plasmon resonance properties results in visible color changes. As an example, we present a simple and sensitive "mix-and-read" chromogenic immunosensor for Cronobacter sakazakii (C. sakazakii). The experiment can be completed within 20 min, with a visual detection limit of 103 CFU/mL and a quantitative detection limit of 136 CFU/mL. Importantly, our method exhibits no cross-reactivity with other bacterial species. This strategy harnesses the excellent properties of nanobodies and the optical characteristics of AuNPs for direct and rapid detection of foodborne pathogen.

Safety and Immunogenicity of an Adjuvanted Clostridioides difficile Vaccine Candidate in Healthy Adults: A Randomized Placebo-Controlled Phase 1 Study.

This study investigated the safety, reactogenicity, and immunogenicity in healthy subjects of a Clostridioides difficile vaccine candidate with/without adjuvant, targeting toxins A and B. In this first-in-human, phase 1, observer-blind study, subjects aged 18-45 years were randomized to receive F2 antigen (n = 10) or placebo (n = 10), and subjects aged 50-70 years to receive F2 antigen plus AS01 adjuvant (n = 45), F2 antigen (n = 45), or placebo (n = 30) in 2 doses 1 month apart. A subcohort (n = 40) received a third dose 15 months later. Solicited adverse events (AEs) were recorded for 7 days and unsolicited AEs for 30 days after each dose. Immunogenicity was assessed at baseline and after each dose. Solicited AEs were transient and most frequent in subjects receiving F2 antigen plus AS01. No serious AEs were considered related to study vaccine. Immunogenicity was substantially higher in subjects receiving F2 antigen plus AS01 than subjects receiving F2 antigen alone. A third dose increased the immune response in subjects with baseline neutralization titers below the assay lower limit of quantitation. The GSK C. difficile vaccine candidate was immunogenic, especially when given with AS01, and was well tolerated with an acceptable safety profile. NCT04026009.

Red-emissive carbon dots from Hibiscus rosa-sinensis: a detailed appraisal of tartrazine dye sensing properties.

Aneconomically viable and greener approach is introduced to fabricate red emissive carbon dots (R@CQDs) via employing hydrothermal means on Hibiscus rosa-sinensis leaves as precursor source. The obtained R@CQDs displayed excitation-dependent behavior, with high aqueous stability, quantum yield of 56%, and outstanding fluorescence aptitude under the conditions of varied range of ionic strength and pH (1-12). The fluorescence emission behavior of R@CQDs displayed selective turn off fluorescenceresponse to tartrazine over other interfering species with alimit of detection of 0.09µM and quantitation limit of 0.30µM. Theoretical calculations employing density functional theory (DFT) were carried out to complement experimental findings and getting insights into the underlying mechanism governing the sensing of tartrazine. The developed sensor holds significant potential for tartrazine detection in real samples and offering wider prospective in the food safety assessment.

Recent Advances (2018–2023) and Research Opportunities in the Study of Groundwater in Cold Regions

ABSTRACTIncreasing greenhouse gas levels drive extensive changes in Arctic and cold‐dominated environments, leading to a warmer, more humid, and variable climate. Associated permafrost thaw creates new groundwater flow paths in cold regions that are causing unprecedented environmental changes. This review of recent advances in groundwater research in cold environments has revealed that a new paradigm is emerging where groundwater is at the center of these changes. Groundwater flow and associated heat and solute transport are now used as a basis to understand hydrological changes, permafrost dynamics, water quality, integrity of infrastructure along with ecological impacts. Although major advances have been achieved in cold regions' cryohydrogeological research, the remaining knowledge gaps are numerous. For example, groundwater as a drinking water source is poorly documented despite its social importance. Lateral transport processes for carbon and contaminants are still inadequately understood. Numerical models are improving, but the highly complex physical‐ecological changes occurring in the arctic involve coupled thermal, hydrological, hydrogeological, mechanical, and geochemical processes that are difficult to represent and hamper quantitative analysis and limit predictive capacity. Systematic long‐term observatories where measurements involving groundwater are considered central are needed to help resolve these research gaps. Innovative transdisciplinary research will be critical to comprehend and predict these complex transformations.

Fast Molecular Recognition of Docosahexaenoic Acid Ethyl Ester in the Liver and Meat of Stingray Using a Miniplatform Based on a 3D Stochastic Microsensor

Docosahexaenoic acid ethyl ester has an important role in the prevention of the neuropsychiatric and neurodegenerative diseases. Its extraction from fish such as the stingray as anoil creates a pharmaceutical formulation. Therefore it is essential to develop fast molecular recognition methods able to perform both qualitative and quantitative determination of docosahexaenoic in stingray meat and liver. A miniplatform incorporating a 3D stochastic microsensor was designed and validated for the molecular recognition of docosahexaenoic acid ethyl ester. The design of the microsensor was based on the modification of a graphene decorated with nitrogen and boron paste (NB-graphene paste) with 10−3mol L−1 alpha-cyclodextrin. A wide linear concentration range (5.0 × 10−14 − 5.0 × 10−7 g mL−1) and a low limit of quantitation (5.0 × 10−14 g mL−1) were obtained. High recovery values were determined when the miniplatform was used for the assay of docosahexaenoic acid ethyl ester from stingray liver and meat with recoveries higher than 99.20%. The relative standard deviation values were less than 0.05 (N = 10).

Simultaneous Quantification of Serum Symmetric Dimethylarginine, Asymmetric Dimethylarginine and Creatinine for Use in a Routine Clinical Laboratory.

Background Symmetric dimethylarginine (SDMA) and asymmetric dimethylarginine (ADMA) are naturally occurring amino acids classed as uremic toxins by the EUTOX working group. SDMA is principally excreted through the kidneys and is a well-known renal function marker, ADMA is a potent inhibitor of nitric oxide production. Here, we describe the development of a rapid and sensitive liquid chromatography tandem mass spectrometry method for simultaneous measurement of SDMA, ADMA and creatinine. Method Serum samples were prepared by protein precipitation and dilution with acetonitrile prior to injection onto a Waters TQS-Micro. Multiple reaction monitoring was used to detect SDMA, ADMA, creatinine, and their corresponding internal standard transitions after separation with a HILIC analytical column. Sample stability and intra-individual variation studies were also assessed following ethical approval. Results The retention time for creatinine was 0.43, SDMA 1.10 and ADMA 1.14 minutes. Mean recovery for creatinine was 103%, SDMA was 100% and ADMA was 103%, matrix effects were minimal (<6%). Lower limit of quantitation for creatinine and SDMA/ADMA was 17.5 µmol/L and 0.1 µmol/L respectively. Analytical imprecision showed a coefficient of variation <10% for all analytes across the working range of the assays. Intra-individual variation for creatinine was 4.7%, SDMA 7.5% and ADMA 7.6%. Discussion We have developed a rapid assay for LC-MS/MS measurement of SDMA, ADMA and creatinine in a routine clinical laboratory. It is simple, reproducible, and easy to perform. The stability of SDMA and ADMA pre- and post-centrifugation allows for their routine use without any special sample handling requirements.

Detection of Veterinary Drugs in Food Using a Portable Mass Spectrometer Coupled with Solid-Phase Microextraction Arrow.

A portable mass spectrometer (PMS) was combined with a mesoporous silica material (SBA-15) coated solid-phase microextraction (SPME) Arrow to develop a rapid, easy-to-operate and sensitive method for detecting five veterinary drugs-amantadine, thiabendazole, sulfamethazine, clenbuterol, and ractopamine-in milk and chicken samples. Equipped with a pulsed direct current electrospray ionization source and a hyperboloid linear ion trap, the PMS can simultaneously detect all five analytes in approximately 30 s using a one-microliter sample. Unlike traditional large-scale instruments, this method shows great potential for on-site detection with no need for chromatographic pre-separation and minimal sample preparation. The SBA-15-SPME Arrow, fabricated via electrospinning, demonstrated superior extraction efficiency compared to commercially available SPME Arrows. Optimization of the coating preparation conditions and SPME procedures was conducted to enhance the extraction efficiency of the SBA-15-SPME Arrow. The extraction and desorption processes were optimized to require only 15 and 30 min, respectively. The SBA-15-SPME Arrow-PMS method showed high precision and sensitivity, with detection limits and quantitation limits of 2.8-9.3 µg kg-1 and 10-28 µg kg-1, respectively, in milk. The LOD and LOQ ranged from 3.5 to 11.7 µg kg-1 and 12 to 35 µg kg-1, respectively, in chicken. The method sensitivity meets the requirements of domestic and international regulations. This method was successfully applied to detect the five analytes in milk and chicken samples, with recoveries ranging from 85% to 116%. This approach represents a significant advancement in food safety by facilitating rapid, in-field monitoring of veterinary drug residues.

A New approach for simultaneous detection and photocatalytic degradation of imidacloprid and dinotefuran in water using terbium-based fluorometry and mixed-phase TiO2

This study explores a novel method for detecting neonicotinoid insecticides, imidacloprid (IMD) and dinotefuran (DNT), in water using terbium (Tb3+) ions photo probe. The optimal excitation and emission wavelengths for Tb3+ luminescence were identified at 310 nm and 545 nm, respectively. The influence of pH and solvent on Tb-complex fluorescence was investigated. Results indicate a significant enhancement of luminescence intensity at pH 6 for IMD in DMF and pH 7.0 for DNT in DMSO. The fluorescence intensity exhibited a linear relationship with IMD and DNT concentrations ranging from 0.1 to 20 µg/mL (R2 > 0.99). Limits of quantitation (LOQ) were determined as 0.1 µg/mL for IMD and 0.05 µg/mL for DNT. This newly developed photo probe demonstrates the potential for monitoring photolysis and photocatalytic degradation of these neonicotinoids using TiO2 as a catalyst under controlled photoreactor conditions. The method offers a promising alternative for rapidly and sensitively detecting these prevalent insecticides in water samples.

Quantification of L-ornithine L-aspartate in health supplement by HPLC in combination with o-phthalaldehyde derivative technique

Dietary supplements containing L-ornithine L-aspartate (LOLA) are on the rise. Thus, a simple, reliable method of analysis for determining LOLA has been developed, which helps to control product quality. In this study, a method for determining LOLA in dietary supplements by HPLC in combination with o-phtalaldehyde derivatives (OPA) was developed and validated. The study optimized conditions for extraction of LOLA from the matrix, then derived with OPA and chromatographic separation on column C18. The detection limits and quantitative limits of the method were conducted on low-content real samples, with LOD and LOQ values achieved at 6.0 and 20.0 &amp;mu;g/g, respectively. The method has good recovery (98 &amp;ndash; 106%) and repeatability (1.32 &amp;ndash; 3.50%) that meet the method performance requirements according to AOAC. The validated method has been applied to analyze LOLA content in dietary supplements at the National Institute for Food Control.