Quantification of Glycated Hemoglobin in Total Hemoglobin by a Simultaneous Dual-Signal Acquisition Approach.

The glycated hemoglobin (HbA1c) level, which is defined as the ratio of HbA1c to total hemoglobin (tHb, including glycated and unglycated hemoglobin), is considered one of the preferred indicators for diabetes monitoring. Generally, assessment of the HbA1c level requires separate determination of tHb and HbA1c concentrations after a complex separation step. This undoubtedly increases the cost of the assay, and the loss or degradation of HbA1c during the separation process results in a decrease in the accuracy of the assay. Therefore, this study explored a dual-signal acquisition method for the one-step simultaneous evaluation of tHb and HbA1c. Quantification of tHb: graphene adsorbed carbon quantum dots and methylene blue were utilized as the substrate material and linked to the antibody. tHb was captured on the substrate by the antibody. The unique heme group on tHb catalyzed the production of •OH from H2O2 to degrade methylene blue on the substrate, and a quantitative relationship between the tHb concentration and the methylene blue oxidation current signal was constructed. Quantification of HbA1c: complex labels with HbA1c recognition were made of ZIF-8-ferrocene-gold nanoparticles-mercaptophenylboronic acid. The specific recognition of the boronic acid bond with the unique cis-diol structure of HbA1c establishes a quantitative relationship between the oxidation current of the label-loaded ferrocene and the concentration of HbA1c. Thus, the HbA1c level can be assessed with only one signal readout. The sensor exhibited extensive detection ranges (0.200-600 ng/mL for tHb and 0.100-300 ng/mL for HbA1c) and low detection limits (4.00 × 10-3 ng/mL for tHb and 1.03 × 10-2 ng/mL for HbA1c).

Construction of a direct Z-scheme Cs3Bi2Cl9/g-C3N4 heterojunction composite for efficient photocatalytic degradation of various pollutants in water: Performance, kinetics and degradation mechanism.

The use of emerging composite materials has been booming to remove environmental pollutants. The aim of this research is to develop a new composite based on Cs3Bi2Cl9 perovskite and graphitic carbon nitride (g-C3N4) to investigate the photocatalytic performance under visible light irradiation. To achieve this, we produce the Cs3Bi2Cl9/g-C3N4 heterojunctions through a simple self-assembly synthesis. The as-synthesized composites are characterized using XRD, FTIR, FESEM, TEM, BET and EDX techniques. The photocatalytic performance of Cs3Bi2Cl9/g-C3N4 is examined in the degradation of various water contaminants, including 4-nitrophenol (4-NP), tetracycline antibiotic (TC), methylene blue (MB) and methyl orange (MO). The experimental results indicate the superior photocatalytic performance of the composites in the degradation of pollutants compared to pure Cs3Bi2Cl9 and g-C3N4. The 10% Cs3Bi2Cl9/g-C3N4 composite achieves the optimal degradation efficiency of 100, 92, 98.7, and 85.1% of 4-NP, TC, MB, and MO, respectively. This superior photocatalytic activity attributes to improved optical and electrochemical properties, including enhanced absorption ability, narrowing band gap, promoted separation efficiency of photogenerated carriers, and a high redox potential, which is confirmed by UV-vis DRS, PL, EIS, and CV analyses. The 10% Cs3Bi2Cl9/g-C3N4 composite also demonstrates high photocatalytic stability after four consecutive cycles. Radical trapping tests show that superoxide radicals (•O2-), holes (h+), and hydroxyl radicals (•OH) contribute to the photocatalytic process. Based on the obtained data, a direct Z-scheme heterojunction mechanism is proposed. Overall, this research offers a new stable photocatalyst with excellent prospect for photocatalytic applications.

Intravital Microscopy Evidence That Methylene Blue Should Be a Vasopressor-Sparing Agent in Sepsis Vasoplegia.

Microvasculature failure is expected in sepsis and at higher amine concentrations. Therefore, special attention focused individually on microcirculation is needed. Here, we present that methylene blue can prevent leukocytes from adhering to the endothelium in a rat model of lipopolysaccharide-induced endotoxemia. As hypothesis evidence, an intravital microscopy image is presented.

A Rare Case of Methemoglobinemia after Ifosfamide Infusion in a 3-Year-Old Patient Treated for T-ALL.

Methemoglobinemia is a potentially life-threatening, rare condition in which the oxygen-carrying capacity of hemoglobin is diminished. We present the case of a 3-year-old boy treated for T-cell acute lymphoblastic leukemia (T-ALL) who developed methemoglobinemia (MetHb 57.1%) as a side effect of ifosfamide administration. Due to his critical condition, the patient was transferred to the intensive care unit (ICU). The therapy included methylene blue administration, an exchange transfusion, catecholamine infusion, and steroids. Improving the general condition allowed for continuing chemotherapy without ifosfamide and completion of the HR2 block. Vigilance for methemoglobinemia as a very rare side effect should be widespread when using ifosfamide in the treatment protocols.

Optimizing Neural Networks for Chemical Reaction Prediction: Insights from Methylene Blue Reduction Reactions.

This paper offers a thorough investigation of hyperparameter tuning for neural network architectures using datasets encompassing various combinations of Methylene Blue (MB) Reduction by Ascorbic Acid (AA) reactions with different solvents and concentrations. The aim is to predict coefficients of decay plots for MB absorbance, shedding light on the complex dynamics of chemical reactions. Our findings reveal that the optimal model, determined through our investigation, consists of five hidden layers, each with sixteen neurons and employing the Swish activation function. This model yields an NMSE of 0.05, 0.03, and 0.04 for predicting the coefficients A, B, and C, respectively, in the exponential decay equation A + B · e-x/C. These findings contribute to the realm of drug design based on machine learning, providing valuable insights into optimizing chemical reaction predictions.

Real-time imaging of ipsilateral parathyroid glands by retrograde injection of methylene blue into the superior thyroid artery: a new intraoperative parathyroid protection method.

BACKGROUND: Postoperative hypoparathyroidism caused by parathyroid injury is a problem faced by thyroid surgeons. The current technologies for parathyroid imaging all have some defects. METHODS: Patients with differentiated thyroid carcinoma (DTC) who underwent unilateral thyroidectomy plus ipsilateral central lymph node dissection were recruited. We dissected the main trunk of the superior thyroid artery entering the thyroid gland and placed the venous indwelling tube into the artery. The sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) were calculated. RESULTS: A total of 132 patients enrolled in this single-arm clinical trial, 105 of them completed retrograde catheterization via the superior artery. The sensitivity was 69.23 and 83.33% respectively. The specificity was 72.91 and 64.89%. The accuracy was 72.91 and 64.89%. The PPV was 85.71 and 81.08%. The NPV was 22.58 and 45.45%. There were no patients with allergic reactions to the methylene blue, or methylene blue toxicity. CONCLUSIONS: Retrograde injection of methylene blue via the superior thyroid artery is an effective and safe method to visualize parathyroid glands. This method can accurately locate the target organ by ultraselecting the blood vessel and injecting the contrast agent while avoiding background contamination and reducing the amount of contrast agent. TRIAL REGISTRATION: Clinical trial registration numbers and date of registration: ChiCTR2300077263、02/11/2023.

Target proteins-regulated DNA nanomachine-electroactive substance complexes enable separation-free electrochemical detection of clinical exosome.

Simple and reliable profiling of tumor-derived exosomes (TDEs) holds significant promise for the early detection of cancer. Nonetheless, this remains challenging owing to the substantial heterogeneity and low concentration of TDEs. Herein, we devised an accurate and highly sensitive electrochemical sensing strategy for TDEs via simultaneously targeting exosomal mucin 1 (MUC1) and programmed cell death ligand 1 (PD-L1). This approach employs high-affinity aptamers as specific recognition elements, utilizes rolling circle amplification and DNA nanospheres as effective bridges and signal amplifiers, and leverages methylene blue (MB) and doxorubicin (DOX) as robust signal reporters. The crux of this separation- and label-free method is the specific response of MB and DOX to G-quadruplex structures and DNA nanospheres, respectively. Quantifying TDEs using this strategy enabled precise discrimination of lung cancer patients (n = 25) from healthy donors (n = 12), showing 100% specificity (12/12), 92% sensitivity (23/25), and an overall accuracy of 94.6% (35/37), with an area under the receiver operating characteristic curve (AUC) of 0.97. Furthermore, the assay results strongly correlated with findings from computerized tomography and pathological analyses. Our approach could facilitate the early diagnosis of lung cancer through TDEs-based liquid biopsy.

Facile fabrication of amorphous Al/Fe based metal-organic framework as effective heterogeneous fenton catalyst for environmental remediation.

This study presents a facile preparation and durable amorphous Fe and Al-based MOF nanoplate (AlFe-BTC MOFs) catalyst with notable stability in Fenton reactions. Rigorous characterization using XRD, HR-TEM, and BET confirms the amorphous nature of the synthesized AlFe-BTC MOFs, revealing mesopores (3.4 nm diameter), a substantial surface area (232 m2/g), and a pore volume of 0.69 cc/g. XPS analysis delineates distinct Al2p and Fe2p binding energy values, signifying specific chemical bonding. FE-SEM elemental mapping elucidates the distinctive distribution of Fe and Al within the framework of AlFe-BTC MOFs. In catalytic activity testing, the amorphous AlFe-BTC MOFs exhibited outstanding performance, achieving complete degradation of Methylene blue (MB) dye and 78% TOC removal over 45 min of treatment under mild reaction conditions. The catalyst's durability was assessed, revealing about 75% TOC removal and complete dye decomposition over five successive recycles, with less than 1 mg/L of Fe and Al leaching. UV-Vis spectra revealed the destruction of MB dye over multiple recycling studies. Based on this finding, the amorphous AlFe-BTC MOF nanoplates emerge as a promising solution for efficient dye removal from industrial wastewater, underscoring their potential in advanced environmental remediation processes.

Novel mint-stalks derived biochar for the adsorption of methylene blue dye: Effect of operating parameters, adsorption mechanism, kinetics, isotherms, and thermodynamics.

The pyrolysis of mint stalks and lemon peels was performed to synthesize mint-stalks (MBC) and lemon-peels (LBC) derived biochars for adsorbing methylene blue (MB). The preparation, characterization, and application of MBC in adsorption have not been reported in the literature. MBC showed higher surface area and carbon content than that of LBC. The removal ratios of MB were 87.5% and 60% within 90 min for MBC and LBC, respectively at pH 7, temperature of 30oC, adsorbent dose of 0.5 g/L, and MB concentration of 5 mg/L. The optimal MBC dose was 1 g/L achieving a removal efficiency of 93.6% at pH 7, temperature of 30oC, contact time of 90 min, and initial dye concentration of 5.0 mg/L. The adsorption efficiency decreased from 98.6% to 31.33% by raising the dye concentration from 3.0 mg/L to 30 mg/L. Further, the increase of adsorbent dose to 10 g/L could achieve 94.2%, 90.3%, 87.6%, and 84.1% removal efficiencies of MB in the case of initial concentrations of 200 mg/L, 300 mg/L, 400 mg/L, and 500 mg/L, respectively. MBC showed high stability in adsorbing MB under five cycles, and the performed analyses after adsorption reaffirmed the stability of MBC. The adsorption mechanism indicated that the adsorption of MB molecules on the biochar's surface was mainly because of the electrostatic interaction, hydrogen bonding, and π-π stacking. Pseudo-second-order and Langmuir models could efficiently describe the adsorption of MB on the prepared biochar. The adsorption process is endothermic and spontaneous based on the adsorption thermodynamics. The proposed adsorption system is promising and can be implemented on a bigger scale. Moreover, the prepared biochar can be implemented in other applications such as photocatalysis, periodate, and persulfate activation-based advanced oxidation processes.

Surface modification of toner-based recyclable iron oxide self-doped graphite nanocomposite to enhance methylene blue and tetracycline adsorption.

An innovative task was undertaken to convert ubiquitous and toxic electronic waste, waste toner powder (WTP), into novel adsorbents. Alkaline modification with KOH, NaOH, and NH4OH was employed for the first time to synthesize a series of surface-modified WTP with enhanced dispersibility and adsorption capacity. XRD, XRF, FTIR, and BET analyses confirmed that the prepared KOH-WTP, NaOH-WTP, and NH4OH-WTP were oxygen-functionalized self-doped iron oxide-graphite nanocomposites. The prepared adsorbents were used to remove methylene blue and tetracycline from aqueous solutions. KOH-WTP (0.1 g/100 mL) adsorbed 80% of 10 mg/L methylene blue within 1 h, while 0.1 g/100 mL NH4OH-WTP removed 72% of 10 mg/L tetracycline in 3 h. Exploring surface chemistry by altering solution pH and temperature suggested that hydrogen bonding, electrostatic interactions, π-π electron stacking, and pore filling were plausible adsorption mechanisms. Scanning electron microscopy revealed a diminishing adsorbents porosity after adsorption proving the filling of pores by the adsorbates. KOH-WTP and NH4OH-WTP removed 77% and 61% of methylene blue and tetracycline respectively in the fourth reuse. The adsorption data of methylene blue and tetracycline fitted the Freundlich isotherm model. The maximum adsorption capacities of KOH-WTP and NH4OH-WTP for methylene blue and tetracycline were 59 mg/g and 43 mg/g respectively. The prepared adsorbents were also compared with other adsorbents to assess their performance. The transformation of waste toner powder into magnetically separable oxygen-functionalized WTP with outstanding recyclability and adsorption capacity showcases a significant advancement in sustainable wastewater treatment. This further aligns with the principles of the circular economy through the utilization of toxic e-waste in value-added applications. Additionally, magnetic separation of surface-modified WTP post-treatment can curtail filtration and centrifugation expenses and adsorbent loss during wastewater treatment.

An electrochemical aptasensor for methylamphetamine rapid detection by single-on mode based on competition with complementary DNA.

A simple and rapid electrochemical sensing method with high sensitivity and specificity of aptamers was developed for the detection of methylamphetamine (MAMP). A short anti-MAMP thiolated aptamer (Apt) with a methylene blue (MB) probe at 3'-end was immobilized on the surface of a gold electrode (MB-Apt-S/GE). The electrochemical signal appeared when MAMP presenting in the sample solution competed with cDNA for binding with MB-Apt-S. Under optimized conditions, the liner range of this signal-on electrochemical aptasensor for the detection of MAMP achieved from 1.0 to 10.0 nmol/L and 10.0-400 nmol/L. LOD 0.88 nmol/L were obtained. Satisfactory spiked recoveries of saliva and urine were also obtained. In this method, only 5 min were needed to incubate before the square wave voltammetry (SWV) analysis, which was much more rapid than other electrochemical sensors, leading to a bright and broad prospect for the detection of MAMP in biological sample. This method can be used for on-site rapid detection on special occasions, such as drug driving scenes, entertainment venues suspected of drug use, etc.

Comparison of conventional unstained lymph nodal harvesting vs methylene blue-stained lymph nodal harvesting in colorectal specimen in staging left-sided colorectal carcinoma: a randomized controlled trial.

BACKGROUND: The management and prognosis of colorectal carcinomas (CRCs) are related to the stage of the disease, which, in turn, relies on the lymph node harvest from the surgical specimen. The guidelines recommend that at least 12 lymph nodes are required, which is not achieved in most resections. In this study, we propose a method to improve the lymph node yield in such cases. This study aimed to determine whether ex vivo injection of methylene blue into the inferior mesenteric artery or its branches improves lymph node retrieval in left-sided CRCs. METHODS: This study was conducted as a single-center, double-blinded, superiority randomized controlled trial. Patients who underwent elective surgery for left-sided CRCs with curative intent were randomized into 2 groups: stained and unstained. The sample size was calculated as 66. In all patients, details of disease stage, history of neoadjuvant therapy, and number of isolated lymph nodes were recorded. RESULTS: The mean number of lymph nodes extracted from the stained group was significantly higher than that from the unstained group (15.9 ± 5.2 vs 9.1 ± 5.7, respectively; P < .001). Among the patients who had received neoadjuvant therapy, the yield was higher in the stained group (P < .001). The yield was found to be greater in patients who had undergone upfront surgery than in those who had undergone neoadjuvant therapy, even in the stained group (100% vs 66.7%, respectively). CONCLUSION: The use of methylene blue injection into resected specimens of left-sided CRCs significantly improved the lymph node yield.

Dynamic monitoring of oxygen partial pressure in photodynamic therapy using pump-probe-based photoacoustic tomography.

Pump-probe-based photoacoustic tomography (PP-PAT) is an innovative and promising molecular imaging technique. In this study, we utilized PP-PAT for the first time, to the best of our knowledge, to monitor the dynamics of oxygen partial pressure (pO2) within murine tumors during photodynamic therapy (PDT) with methylene blue (MB). We developed, to our knowledge, a novel two-step fitting method to simultaneously map both the pO2 and the MB concentrations and implemented it with mexCuda to accelerate the pixel-wise-based calculation. The results demonstrated a penetration depth of up to 5 mm and revealed a significant decrease in pO2 during the PDT process, consistent with existing research findings. This study suggests that PP-PAT has the potential to become a valuable tool for intraoperative monitoring of PDT, thereby enhancing therapeutic efficacy.

A novel ZnCo2O4/BiOBr p-n/Z-scheme heterojunction photocatalyst for enhancing photocatalytic activity.

In this study, we developed a novel p-n/Z-scheme heterojunction photocatalyst, ZnCo2O4/BiOBr (ZCo/BB), through a straightforward and safe hydrothermal-calcination-solvent thermal method. The composite photocatalyst demonstrated exceptional photocatalytic efficacy, particularly when the mass ratio of ZnCo2O4 was 25% (referred to as 25% ZCo/BB). Structural characterization and electrochemical analysis revealed that 25% ZCo/BB exhibited a larger specific surface area and a faster electron transfer rate. Under visible light exposure for 30 min, methylene blue (MB) degradation reached 92%, and the reaction rate constants were 8.2 and 3.7 times higher than those observed for individual ZnCo2O4 and BiOBr, respectively. Furthermore, the 25% ZCo/BB demonstrated exceptional photocatalytic stability over four cycles, maintaining over 80% MB degradation after each cycle. The outstanding photocatalytic activity was attributed to the p-n/Z-scheme heterojunction construction, which promoted charge separation and inhibited carrier recombination. In addition, ·OH and h+ were the major active species in photocatalysis, and · O 2 - was identified as a secondary active species. This work presents an efficient heterojunction photocatalyst for the degradation of organic wastewater.

Use of hydroxocobalamin to treat intraoperative vasoplegic syndrome refractory to vasopressors and methylene blue during liver transplantation.

INTRODUCTION: For patients with catecholamine-resistant vasoplegic syndrome (VS) during liver transplantation (LT), treatment with methylene blue (MB) and/or hydroxocobalamin (B12) has been an acceptable therapy. However, data on the effectiveness of B12 is limited to case reports and case series. METHODS: We retrospectively reviewed records of patients undergoing LT from January 2016 through March 2022. We identified patients with VS treated with vasopressors and MB, and abstracted hemodynamic parameters, vasopressor requirements, and B12 administration from the records. The primary aim was to describe the treatment efficacy of B12 for VS refractory to vasopressors and MB, measured as no vasopressor requirement at the conclusion of the surgery. RESULTS: One hundred one patients received intraoperative VS treatment. For the 35 (34.7%) patients with successful VS treatment, 14 received MB only and 21 received both MB and B12. Of the 21 patients with VS resolution after receiving both MB and B12, 17 (89.5%) showed immediate, but transient, hemodynamic improvements at the time of MB administration and later showed sustained response to B12. CONCLUSION: Immediate but transient hemodynamic response to MB in VS patients during LT supports the diagnosis of VS and should prompt B12 administration for sustained treatment response.

In-situ synthesis of ZIF-8 on magnetic pineapple leaf biochar as an efficient and reusable adsorbent for methylene blue removal from wastewater.

The presence of organic dyes in aquatic systems poses a significant threat to ecosystems and human well-being. Due to recycling challenges, traditional commercial activated carbon is not cost-effective. To address this, an imidazolate acid zeolite framework-8 (ZIF-8)-modified magnetic adsorbent (ZMPLB-800) was synthesized through the in-situ formation of ZIF-8 and subsequent carbonization at 800 °C, using magnetic pineapple leaf biochar (MPLB) as a carrier. The porous structure of ZMPLB-800 facilitates the rapid passage of dye molecules, enhancing adsorption performance. ZMPLB-800 exhibited remarkable adsorption capacity for methylene blue (MB) across a pH range of 3-13, with a maximum adsorption capacity of 455.98 mg g-1. Adsorption kinetics and thermodynamics followed the pseudo-second-order kinetic model and Langmuir isotherm model. Mechanisms of MB adsorption included pore filling, hydrogen bonding, electrostatic interactions, π-π interactions, and complexation through surface functional groups. Additionally, ZMPLB-800 demonstrated excellent regeneration performance, recording a removal efficiency exceeding 87% even after five adsorption/desorption cycles. This study provides a novel strategy for treating dye wastewater with MOF composites, laying the foundation for waste biomass utilization.

Waste treats waste: Facile fabrication of porous adsorbents from recycled PET and sodium alginate for efficient dye removal.

Dye-contaminated water and waste plastic both pose enormous threats to human health and the ecological environment, and simultaneously solving these two issues in a sustainable and resource-saving way is highly important. In this work, a sodium alginate-polyethylene terephthalate-sodium alginate (SA@PET) composite adsorbent for efficient dye removal is fabricated using wasted PET bottle and marine plant-based SA via simple and energy-efficient nonsolvent-induced phase separation (NIPS) method. Benefiting from its porous structure and the abundant binding sites, SA@PET shows an excellent methylene blue (MB) adsorption capacity of 1081 mg g-1. The Redlich-Peterson model more accurately describes the adsorption behavior, suggesting multiple adsorption mechanisms. In addition to the electrostatic attractions of SA to MB, polar interactions between the PET matrix and MB are also identified as adsorption mechanisms. It is worth mentioning that SA@PET could be recycled 7 times without a serious decrease in performance, and the trifluoroacetic acid-dichloromethane solvent involved in the NIPS process has the possibility of reuse and stepwise recovery. Finally, the discarded adsorbent could be completely degraded under mild conditions. This work provides not only a composite adsorbent with excellent cationic dye removal performance for wastewater treatment, but also an upcycling strategy for waste PET.

Prediction and optimizing of methylene blue sequestration to activated charcoal/magnetic nanocomposites using artificial neutral network and response surface methodology.

Green synthesized magnetic nanoparticles (MNPs) linked with activated charcoal (AC) (AC/Fe3O4 NCs) were exploited for methylene blue (MB) confiscation in this study. The AC/Fe3O4 NCs produced were characterized using TEM, FTIR, UV/Vis and XRD spectrometry. The Response-Surface-Methodology (RSM) was utilized to improve the experimental data for the MB sorption to AC/Fe3O4 NCs, with 20 experimental runs implemented through a central composite design (CCD) to assess the effect of sorption factors-initial MB concentration, pH and sorbent dosage effects on the response (removal-effectiveness). The quadratic model was discovered to ideally describe the sorption process, with an R2 value of 0.9857. The theoretical prediction of the experimental data using the Artificial-Neural-Network (ANN) model showed that the Levenberg-Marquardt (LM) had a better performance criterion. Comparison between the modelled experimental and predicted data showed also that the LM algorithm had a high R2 of 0.9922, which showed NN model applicability for defining the sorption of MB to AC/Fe3O4 NCs with practical precision. The results of the non-linear fitting (NLF) of both isotherm and kinetic models, showed that the sorption of MB to AC/Fe3O4 NCs was perfectly described using the pseudo-second-order (PSOM) and Freundlich (FRHM) models. The estimated optimum sorption capacity was 455 mg g-1. Thermodynamically, the sorption of MB to AC/Fe3O4 NCs was shown to be non-spontaneous and endothermic.

Development of a magnetic nanocomposite sorbent (NiCoMn/Fe3O4@C) for efficient extraction of methylene blue and Auramine O.

A rapid and efficient method for the simultaneous monitoring and recovery of Auramine O (AO) and Methylene Blue (MB) dyes from water samples is presented. This method, named ultrasound-assisted dispersive-magnetic nanocomposites-solid-phase microextraction (UA-DMN-µSPE), utilizes NiCoMn/Fe3O4@C composite sorbents. Response surface methodology (RSM) combined with artificial neural networks (ANN) and generalized regression artificial neural network (GRNN) under central composite design (CCD) was employed to optimize various parameters for efficient extraction, followed by further refinement using desirability function analysis (DFA) and genetic algorithms (GA). Under optimized conditions, the method achieved exceptional recovery rates (99.5 ± 1.2% for AO and 99.8 ± 1.1% for MB) with acetone as the eluent. Additionally, a high preconcentration factor of 45.50 and 47.30 for AO and MB, respectively, was obtained. Low detection limits of 0.45 ng mL⁻1 (AO) and 1.80 ng mL⁻1 (MB) were achieved with wide linear response ranges (5-1000 and 5-2000 ng mL⁻1 for AO and MB, respectively). The method exhibited good stability with RSDs below 3% for five recycling runs, and minimal interference from various ions was observed. This UA-DMN-µSPE-UV/Vis method offers significant advantages in terms of efficiency, preconcentration, and detection limits, making it a valuable tool for the analysis of AO and MB in water samples.