Ultraviolet Detection Research Articles

Convenient determination of polystyrene microplastics in soils by gel permeation chromatography-ultraviolet detection analysis

Microplastics (MPs), especially polystyrene microplastics (PS-MPs), have emerged a new worldwide pollutant, prompting significant public concern regarding their detection in environmental media. Analysis of PS-MPs in soil remains as a challenging task for analysts due to the highly intricate matrices. This work presents a practical approach for detecting PS-MPs in soil, which involves dilute HCl-assisted extraction and gel permeation chromatography- ultraviolet detection (GPC-UV) analysis. The presence of MPs in soil was confirmed through the use of a scanning electron microscope in conjunction with energy dispersive spectroscopy investigation. PS-MPs was isolated from soil, by agitating it with a diluted HCl solution, filtering the resulting liquid, and dissolving the residue on the filter with THF. The extractant was subsequently determined by GPC-UV. The introduction of a small amount of HCl into the extraction system was found to greatly expedite the settling of soil in water and enhance the efficacy of extracting PS-MPs in about 30 min. The linear range of PS-MPs was from 1.0 to 100 μg/mL with R2 > 0.999. Good reproducibility was obtained with the intra-day relative standard deviation (RSD, n = 3) of 1.36 % and the inter-day RSD (n = 3) of 4.78 %. The concentration of PS-MPs in soil samples were N.D. - 2.33 μg/g, and the good recoveries were 76.7–100.3 %. The corresponding AFGEEprer score was calculated to be 0.59, indicating the concept of green analytical chemistry for the pretreatment method. These results indicated that this method has a powerful potential for the accurate and rapid determination of PS-MPs in soil.

Quantification of the Plasma Concentration of Vadadustat by High-Performance Liquid Chromatography with Ultraviolet Detection and Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry.

An inexpensive, simple, and accurate plasma concentration measurement system is needed to actively conduct pharmacokinetic and pharmacodynamic analyses of vadadustat, hypoxia-inducible factor-prolyl hydroxylase inhibitor, in clinical settings. In this study, the authors aimed to develop a method for measuring vadadustat in human plasma that could be applied for therapeutic drug monitoring using high-performance liquid chromatography with ultraviolet detection (HPLC-UV) in a clinical setting. Plasma samples (100 μL) were pretreated with acetonitrile using butyl paraoxybenzoate as an internal standard. Chromatographic separation was performed on a SunShell PFP C18 column (2.6 μm, 4.6 mm × 150 mm). The mobile phase consisted of (A) 20 mM of phosphate buffer (pH 2.4) and (B) acetonitrile (60:40, v/v), delivered isocratically at a flow rate of 1 mL/min. The analytes were detected by UV absorbance at a wavelength of 220 nm, and the column temperature was 40°C. To evaluate the applicability of HPLC-UV in a clinical setting, blood samples were collected at 19 time points from 7 patients who had been taking vadadustat. The calibration curve was linear over the concentration range of 0.2-150 mcg/mL (R2 > 0.99). Intra-assay and interassay accuracy, precision, and stability met the Food and Drug Administration recommendations. The vadadustat plasma concentrations of patients analyzed using the current HPLC-UV method were almost equal to those measured using ultra-performance liquid chromatography-tandem mass spectrometry (mean difference: 0.13 mcg/mL). Large variability in the dose-adjusted plasma concentrations of vadadustat at 12 hours after administration was observed between patients (coefficient of variation = 57.6%). This HPLC-UV method is a simple, accurate quantification method for evaluating plasma concentrations in patients taking vadadustat in a clinical setting.

Validation of a bioanalytical HPLC-UV method to quantify Α-Bisabolol in rat plasma applied to pharmacokinetic pilot study with the drug nanoemulsion.

α-Bisabolol (α-BIS) is a sesquiterpene alcohol present in chamomile essential oil [Chamomilla recutita (L.) Rauschert]. Despite its numerous pharmacological effects, its pharmacokinetics remain understudied. An analytical method capable of quantifying α-BIS in plasma is crucial to enable pharmacokinetic analysis. Presently, only one study has quantified it using mass spectrometry. Administering α-BIS requires a nanoemulsion for intravenous injection. This study aimed to develop and validate a bioanalytical method using high-performance liquid chromatography with an ultraviolet detector to quantify α-BIS in rat plasma. The method employed acetonitrile and ultrapure water (80:20, v/v) as the mobile phase, with a flow rate of 1ml/min and concentrations ranging from 465 to 29.625 μg/ml. All US Food and Drug Administration-designated assays were successful, indicating the method's precision, accuracy, sensitivity and linearity in determining α-BIS in rat plasma. The developed nanoemulsion, assessed through dynamic light scattering analysis, the ensemble collection of particles and polydispersity index evaluation, proved safe and effective for intravenous administration. The pharmacokinetic parameters such as volume of distribution, clearance and half-life indicated that α-BIS tends to persist in the body. This study provides a foundation for further research to explore α-BIS's potential pharmaceutical applications in the future.

Preparation of Sn-Doped Ga2O3 Thin Films and MSM Ultraviolet Detectors Using Magnetron Co-Sputtering.

Sn-doped Ga2O3 thin films and metal-semiconductor-metal (MSM) ultraviolet detectors were prepared using the co-sputtering method to enhance their photoelectric performance. The results revealed that Sn doping can effectively change the optical and electrical properties of thin films, greatly improving the photoelectric responsiveness of the devices. Through microstructure testing results, all of the thin film structures were determined to be monoclinic beta phase gallium oxide. At a DC power of 30 W, the thickness of the Sn-doped thin film was 430 nm, the surface roughness of the thin film was 4.94 nm, and the carrier concentration, resistivity, and mobility reached 9.72 × 1018 cm-3, 1.60 × 10-4 Ω·cm, and 45.05 cm3/Vs, respectively. The optical results show that Sn doping clearly decreases the transmission of thin films and that the bandgap can decrease to 3.91 eV. Under 30 W DC power, the photo dark current ratio of the detector can reach 101, time responses of tr = 31 s and tf = 22.83 s were obtained, and the spectral responsivity reached 19.25 A/W.

Luminescent fiber UV detection.

Herein, a luminescent fiber device for detecting ultraviolet (UV) intensity, which comprises a UV probe and a photoelectric converter, is proposed. The UV probe consists of a glass tube filled with luminescent material, which can be used for the efficient radiation conversion of UV radiation to the visible spectral region. The luminescent material, Y2O2S:Eu3+, is mixed with polydimethylsiloxane (PDMS) to form the core of the UV probe. Subsequently, the UV radiation response of the luminescent fiber device is investigated; the experimental results demonstrate that the direction-independent UV detection can be realized by using this luminescent fiber UV detection device while UV light is radiated radially along the UV probe. In addition, since partial discharge (PD) is accompanied by UV radiation, we hope to develop a spectral PD detection scheme based on optical fiber technology, which can broaden the role of optical technology and optical fiber technology in the field of PD detection.

Quantification of amino acids secreted by yeast cells by hydrophilic interaction liquid chromatography-tandem mass spectrometry.

Monitoring the levels of amino acids (AAs) in biological cell cultures provides key information to understand the regulation of cell growth and metabolism. Saccharomyces cerevisiae can naturally excrete AAs, making accurate detection and determination of amino acid levels within the cultivation medium pivotal for gaining insights into this still poorly known process. Given that most AAs lack ultraviolet (UV) chromophores or fluorophores necessary for UV and fluorescence detection, derivatization is commonly utilized to enhance amino acid detectability via UV absorption. Unfortunately, this can lead to drawbacks such as derivative instability, labor intensiveness, and poor reproducibility. Hence, this study aimed to develop an accurate and stable hydrophilic interaction liquid chromatography-tandem mass spectrometry analytical method for the separation of all 20 AAs within a short 17-min run time. The method provides satisfactory linearity and sensitivity for all analytes. The method has been validated for intra- and inter-day precision, accuracy, recovery, matrix effect, and stability. It has been successfully applied to quantify 20 AAs in samples of yeast cultivation medium. This endeavor seeks to enhance our comprehension of amino acid profiles in the context of cell growth and metabolism within yeast cultivation media.

High-performance transparent AZO UV photodetectors

In this work, the fabrication of undoped ZnO (ZO) and 3 at.% aluminum (Al) doped ZnO (AZO) thin films (TFs) based transparent photodetectors (PDs) was reported. Both films were spin-coated on fluorine-doped tin oxide (FTO) substrates to investigate the influence of Al doping on the ultraviolet (UV) detection performance of the devices. The systematic characterizations reveal that Al doping positively affects the characteristics of ZO-TFs. The Al doping leads to slight shift in crystalline peaks and induces an enhancement in grain size. In addition, the surface roughness of ZO-TFs gets lower on Al doping. Further, the Al doping improved the transparency and widening of band gap of TFs. The PDs having metal–semiconductor-metal (MSM) configuration were achieved by screen-printing of Ag paste onto ZO and AZO-TFs. The current–voltage (I-V) profiles of the fabricated PDs were measured in the dark and under UV excitation of 365 nm. The AZO-TFs based MSM PD exhibits a spectral responsivity of 326.82 mA/W and an external quantum efficiency of 111.03%. The reproducibility of the fabricated PDs was tested by performing time-dependent photo-response measurements.

Fabrication and high photoresponse performance of a La-doped HfO2 thin film-based UV photodiode

The ability to detect ultraviolet light is crucial for various applications such as energy harvesting, environmental monitoring, sensing, and ultraviolet astronomy. In this paper, we determined the photoelectric properties of a photodiode based on an interfacial layer of a La-doped HfO2 (HfLaO) thin film. We carried out several tests to analyze the electrical behavior and photoresponse of the Au/HLO/p-Si photodiode under ultraviolet (UV) and white light illumination and in the dark. The chemical composition, surface morphology, cross-sectional thickness, optical properties, and crystalline structure of the HfLaO (HLO) film prepared by the sol-gel method were characterized. We found that the prepared photodiode exhibited excellent repeatability and stability. Moreover, the photocurrent increased with increasing UV light intensity. When the UV light intensity was 23.5 mW/cm2, the photocurrent reached 700 μA and remained unsaturated at a 7 V bias voltage. Moreover, we systematically analyzed the changes in the energy bands and carriers under dark and ultraviolet light conditions to further understand the working mechanism of the photodiode. Overall, the Au/HLO/p-Si photodiode had excellent ultraviolet detector performance and could be a strong candidate for optoelectronic applications.

Occurrence and risk estimation of zearalenone and deoxynivalenol in oats, wheat flour, and cereals consumed in Chile during 2016–2022

Mycotoxin contamination in agricultural products is a significant food safety and public health concern globally. However, little is known about the occurrence and levels of deoxynivalenol (DON) and zearalenone (ZEN) in agri-food product in Chile. In this study, high-performance liquid chromatography coupled with fluorescence detection (HPLC-FLD) and ultraviolet detector (HPLC-UV) were employed to analyze the levels of ZEN and DON in oats, wheat flour, and cereals marketed in Chile and assess the exposure of Chilean individuals through the consumption. The presence of ZEN and DON during 2016–2022 was not considerable. Nonetheless, a higher prevalence of DON was observed in wheat flour (6.1 %) than in cereals (1.2 %) in different regions of Chile, without concentrations exceeding national regulations (750 ngg−1). The only positive sample for ZEN exceeded the international regulations (75 ngg−1) for cereals by 30-fold (2302 ngg−1). The Estimated daily intake (EDI) and Hazard quotient (HQ) for DON indicated no risk to human health. Meanwhile, the EDI for ZEN exceeded the Tolerable daily intake (TDI: 250 ngkg−1 day). Consequently, the HQ for ZEN was 7.7 (2–5 years) and 4.3 (6–13years), indicating a risk to children and adolescents, which are vulnerable age groups. We recommended increasing the frequency of mycotoxin monitoring for highly consumed agri-food products, considering that Chile is highly susceptible to the effects of climate change that promote the natural proliferation of mycotoxins.

A UPLC Method for Simultaneous Estimation of Trastuzumab and Hyaluronidase in Bulk and Pharmaceutical Dosage Form

Objective: The proposed research aimed at establishing a quick, accurate, and exact ultra-performance liquid chromatography (UPLC) methodology for contemporaneously analyzing trastuzumab and hyaluronidas in bulk and pharmaceutical formulation, with a focus on the stability-indicating properties of the assay. Method: Using a Water X-Bridge C18 column (50 mm x 4.6 mm x 2.5 μ) and a mobile phase of ACN: Buffer (pH 2.5) [50% v/v], pushed at 0.5 mL/min, compounds were separated chromatographically. An ultraviolet (UV) detector fixed at 260 nm was employed to identify the isolated compounds. Results: The findings showed that 1.3529 and 2.404 minutes were optimal for separating Trastuzumab and Hyaluronidase, correspondingly. The current procedure has been verified in accordance with ICH standards Q2 R1, and stability-indicating tests have been performed in accordance with ICH standards Q1A R2. Both the intra- and inter-day precisions were determined to be satisfactory. The suggested approach showed linearity between 30 to 180 μg/mL of trastuzumab and between 12.50-75μg/ mL of hyaluronidase. It was determined that the limit of detection (LoD) and limit of quantitation (LoQ) for trastuzumab were 0.36 and 1.2 μg/mL, correspondingly, whereas those for hyaluronidase were 0.15 and 0.5 μg/mL. The approach was shown to have a recovery rate around 98.6 to 99.7%. Conclusion: The suggested approach successfully separated the chemical compounds from their by-products. Therefore, trastuzumab and hyaluronidase routine evaluation and stability-indicating tests were both effectively implemented using the approach.

Estimation of Imeglimin in Pharmaceutical Tablets by RP-HPLC

Objective: This study’s primary goal is to create a novel, sensitive and comprehensive reverse phase-high performance liquid chromatography (RP-HPLC) procedure. The computation of Imeglimin’s dose and dosage is the primary goal. Method: Chemicals and impurities were separated chromatographically using a C18 (AGILENT) chromatographic column. Methanol and 0.1% OPA are present in the mobile phase in a 40:60 v/v ratio. A 240 nm ultraviolet light detector was employed for the purpose of detection. With a retention time of 4.718 minutes, the results demonstrated the effectiveness of meglimin. After adjusting the flow rate to 0.7 mL/min, there was good separation. There are several imeglimin doses planned, ranging from 10 to 50 μg/mL. 101.46 to 101.12% in yield. Results: This method’s validation has good accuracy, sensitivity, precision, linearity, specificity, and robustness, and it satisfies the requirements of the International Conference on Harmonization. Conclusion: In conclusion, imeglimin was predicted and the construction method was isolated. In conclusion, it’s feasible for daily use.

Analysis of cassine and spectaline in the Senna spectabilis ethanolic extracts by capillary zone electrophoresis with indirect UV detection.

2,6-Disubstituted piperidin-3-ols are an important group of piperidine alkaloids found in species such as Senna spectabilis, whose main constituents include cassine and spectaline, compounds with relevant pharmacological activity. The analysis of these compounds is challenging due to the complexity of plant extracts and the absence of chromophores capable of absorbing ultraviolet (UV) radiation. This paper presents a new analytical method to separate and quantify the non-UV-absorbing alkaloids present in ethanol extracts from S. spectabilis flowers using capillary zone electrophoresis (CZE) with indirect UV detection. The optimized CZE method employs a background electrolyte containing 60 mM histidine (His), 15 mM α-cyclodextrin, 20% acetonitrile (ACN), and pH-adjusted to 4.7 with acetic acid (AcOH). The limit of detection (LOD) values was 10.2 and 13.9mg L-1 for cassine and spectaline, respectively. For both analytes, the precision data were better than 2% of relative standard deviation (RSD) for migration times and peak areas. To evaluate the applicability of the developed method, ethanolic extracts from S. spectabilis flowers were prepared and analyzed. Thereby, the method proved to be efficient and complementary to conventional techniques, offering a cost-effective alternative in the quantification of the non-UV-absorbing piperidine alkaloids present in plant extracts.

Development and Validation of a High-Performance Liquid Chromatography Coupled With Ultraviolet Detection Method for Quantification of Bictegravir in Human Plasma.

To establish a method for determining the bictegravir (BIC) concentration in human plasma using high-performance liquid chromatography coupled with ultraviolet detection. The analysis was performed on a CLC-octadecylsilane column (150 × 6.0 mm, 5 μm) using a mixture of phosphate buffer and acetonitrile (62:38, v/v) as the mobile phase at the flow rate of 1.4 mL/min. The column temperature was maintained at 40°C. Using triamcinolone acetonide as the internal standard, 100 μL of plasma sample was extracted by methyl tert-butyl ether, followed by evaporating under nitrogen stream, redissolving with 100 μL mobile phase, and injection of 20-40 μL of supernatant into the chromatographic system. Ultraviolet detection was performed at 260 nm, and the total run time for each sample was 14 minutes. The method exhibited good linearity within the range from 0.10 to 10.0 mcg/mL (r = 0.9995, n = 5). The intraday and interday relative standard deviations for low-, medium-, and high-concentration quality control samples (0.20, 4.00, 8.00 mcg/mL) and the lower limit of quantification (0.10 mcg/mL) were 1.31%-6.20% (n = 10) and 1.18%-2.87% (n = 5), respectively. The intraday and interday accuracies were 100.53%-102.32% and 97.96%-103.84%, respectively. The extraction recovery rates ranged from 80.00% to 88.09% (n = 3). The stability tests showed that the BIC concentration changed by <15%. This study successfully established a high-performance liquid chromatography coupled with ultraviolet detection method for determining plasma BIC concentrations. This method is simple, selective, sensitive, and accurate, making it suitable for clinical monitoring and pharmacokinetic studies of BIC.

Simultaneous Determination of Ethyleneamines by Reversed-Phase Ion-Pair Chromatography with Ultraviolet Detection Using on-Line Complexation with Copper(II) Ion

Simultaneous Determination of Ethyleneamines by Reversed-Phase Ion-Pair Chromatography with Ultraviolet Detection Using on-Line Complexation with Copper(II) Ion

A new method for quantification of tomatine-enriched extracts.

Green tomato extracts, an agro-food industry waste, are rich in the glycoalkaloid tomatine, which presents activity against several diseases. High-performance liquid chromatography (HPLC) with ultraviolet (UV) detection is one of the most used techniques for quantification of bioactive compounds. The aim of this study was to optimize and validate a selective HPLC method with diode array detector (DAD) for the quantitative analysis of tomatine extracted from green tomatoes by subcritical water. Chromatographic runs were performed on a InertSustain Phenyl (250 mm × 4.6 mm, 5 μm) analytical column, at a wavelength of 205 nm. A concentration range of 50-580 μg mL-1 was used. The validation process was performed considering the linearity, precision, trueness, limit of detection (LOD) and limit of quantitation (LOQ) of the method. The selected mobile phase composed of acetonitrile and a solution of 20 mmol L-1 potassium dihydrogen phosphate (KH2PO4) pH 3, resulted in suitable retention times and a standard calibration curve with adequate linearity (R2 = 0.9999). The method trueness was evaluated by the recovery assay, obtaining a mean recovery of 105% and the precisions were 1.4% and 0.9% (percentage relative standard deviation, RSD%) for the tomatine standard and extract samples, respectively. The inter-day variability was 2.7-9.0% (RSD%) for the standards and 6.9% (RSD%) for extract. The LOD and the LOQ of the method were determined at 8.0 and 24.1 μg mL-1, respectively. The herein described method was successfully used for the quantification of tomatine in a tomato-derived extract. Furthermore, the method constitutes a simple and rapid analytical approach able to be used as a routine protocol. © 2024 Society of Chemical Industry.

Exploring the Efficacy of Using Geotrichum fermentans, Rhodotorula rubra, Kluyveromyce marxiamus, Clay Minerals, and Walnut Nutshells for Mycotoxin Remediation.

The aim of this study was to evaluate the effectiveness of nine different biological compounds to reduce mycotoxins concentrations. The hypothesis of this study was that a static in vitro gastrointestinal tract model, as an initial screening tool, can be used to simulate the efficacy of Geotrichum fermentans, Rhodotorula rubra, Kluyveromyce marxiamus yeast cell walls and their polysaccharides, red and white clay minerals, and walnuts nutshells claiming to detoxify AFB1, ZEA, DON, and T-2 toxin mycotoxins. Mycotoxin concentrations were analyzed using high-performance liquid chromatography (HPLC) with fluorescent (FLD) and ultraviolet detectors (UV). The greatest effects on reducing mycotoxin concentrations were determined as follows: for AFB1, inserted G. fermentans cell wall polysaccharides and walnut nutshells; for ZEA, inserted R. rubra and G. fermentans cell walls and red clay minerals; for DON, R. rubra cell wall polysaccharides and red clay minerals; and for T-2 toxin, R. rubra cell walls, K. marxianus, and G. fermentans cell wall polysaccharides and walnut nutshells. The present study indicated that selected mycotoxin-detoxifying biological compounds can be used to decrease mycotoxin concentrations.

An ultra-wide-angle metasurface absorber operating in the ultraviolet to visible range

Here, we propose an ultra-wide-angle metasurface absorber. It consists of a one-dimensional titanium grating periodic array with dislocation distribution. The average absorptivity of the absorber exceeds 94% in the ultraviolet to visible light band (200–760 nm) under normal TM-polarized incident wave. This benefits from the coupling of propagating surface plasmon resonance, local surface plasmon resonance, and hybrid mode resonance. For normal TE-polarized incident wave, the absorber achieves perfect narrowband absorption (>99.22%) in the ultraviolet light region because of the excitation of cavity-mode resonance. The absorber exhibits broadband absorption with an average absorptivity exceeding 85% in the visible light band because of the excitation of slot mode. These excellent absorption properties are well retained at 70° oblique incidence. The structural symmetry of the absorber dramatically expands the flexibility of device applications. It can achieve great absorption performance in an ultra-wide-angle range of 280° along the incident light direction. In addition, the absorber is sensitive to the polarization angle and incident angle of ultraviolet light, which can be used for ultraviolet detection and sensing. The proposed ultra-wide-angle metasurface absorber has potential application in the field of optical communication, photoelectric detection, and solar energy harvesting.

Development and Validation of a High-Performance Liquid Chromatography With Ultraviolet Detection Method to Facilitate Therapeutic Monitoring of Teicoplanin Using Dried Blood Spots.

In neonatal and pediatric intensive care units, Gram -positive infections are a significant cause of morbidity and mortality. The increase in infections caused by methicillin-resistant Staphylococcus aureus and methicillin-resistant coagulase-negative Staphylococci have led to the increased use of glycopeptides, which treat invasive infections caused by Gram -positive organisms, particularly those resistant to beta-lactam antibiotics. Teicoplanin has bacteriostatic activity against Gram -positive bacteria, but its pharmacokinetics in children is highly variable, with most children failing to reach target levels at the recommended dose. This study aimed to develop a cost-effective method for determining concentrations using dried blood spot (DBS). A method to determine the concentrations of teicoplanin in 20 µL blood or plasma using the Whatman 903 Protein Saver filter was evaluated. High-performance liquid chromatography with ultraviolet detection high-performance liquid chromatography with ultraviolet/vis was used, with internal standard ketoconazole. In addition, a method to quantify teicoplanin using 50 µL of liquid plasma was established to compare the results with the values obtained by DBS and dried plasma methods. The method was successfully developed and validated for 20 µL DBS. Furthermore, 50 µL of plasma was used to quantify teicoplanin with a lower limit of quantification of 10 mg/L. Precision and accuracy ranged from 2.3% to 10.7% and 95%-114.2%, respectively. A consistent factor (1.15) was used to calculate teicoplanin plasma concentrations from whole blood, indicating the reliability of the DBS method for therapeutic drug monitoring of teicoplanin. A simple, reliable, and cost-effective method using high-performance liquid chromatography with ultraviolet/vis was established to determine pediatric teicoplanin concentrations in both small plasma sample volumes and whole blood using DBS, and an accurate correlation factor for estimating teicoplanin plasma concentrations from DBS was identified. This method is suitable for the use in pediatrics.

Ultraviolet spectrum-based molecular precision detection

Ultraviolet spectrum-based molecular precision detection

Configuration design of 2D graphene/3D AlGaN van der Waals junction for high-sensitive and self-powered ultraviolet detection and imaging

Configuration design of 2D graphene/3D AlGaN van der Waals junction for high-sensitive and self-powered ultraviolet detection and imaging