Performance of urine samples compared to cervical samples for detection of precancer lesions among HPV-positive women attending colposcopy clinic in Mexico City.

BACKGROUND: High-risk human papillomavirus (hrHPV) detection in self-collected urine samples (SeCUS) may be a promising alternative for cervical cancer screening because of its greater acceptability, as long as it can offer comparable sensitivity to clinician-collected cervical samples (CCoS) for detecting precancer lesions. OBJECTIVE: To evaluate the performance of the SeCUS compared to that of the CCoS for cervical intraepithelial neoplasia grade 3 (CIN3) detection among hrHPV-positive women receiving colposcopy in Mexico City using different specific extended HPV typing procedures: HPV16/18, HPV16/18/35/39/68 or HPV16/18/35/39/68/31. METHODS: From March 2017 to August 2018, 4,158 female users of the cervical cancer screening program at Tlalpan Sanitary Jurisdiction in Mexico City were invited to participate in the FRIDA-Tlalpan study. All participants provided ≥ 30 mL of SeCUS, and then a CCoS was obtained with Cervex-Brush®, which was used for hrHPV typing. Participants who tested positive for hrHPV in CCoS were referred for colposcopy for diagnostic confirmation, and all SeCUS of these women were also tested for hrHPV typing. RESULTS: In total, 561 hrHPV-positive women were identified by CCoS via colposcopy, and 82.2% of the SeCUS of these women were also hrHPV positive. From both CCoS and SeCUS, 7 cases of CIN3 were detected. Considering HPV16/18 typing, CCoS and SeCUS detected 4 cases of CIN3, but after HPV16/18/35/39/68/31 extension typing, both CCoS and SeCUS detected all 7 of the CIN3 cases among the hrHPV-positive women. CONCLUSIONS: Using extended hrHPV typing based on HPV16/18/35/39/68/31, our results suggest that the performance of SeCUS may be equivalent to that of CCoS for detecting CIN3 lesions. Although our results are inconclusive, they support the hypothesis that SeCUS may be an attractive alternative worthy of further research.

Iridium(III) solvent complex-based electrogenerated chemiluminescence method for the detection of 3-methylhistidine in urine.

3-Methylhistidine (3-MeHis) is increasingly used as an indicator of muscle protein breakdown. The development of a sensitive, simple, and non-invasive method for 3-MeHis assay is important in clinical practice. Herein, a sensitive, simple, and non-invasive electrogenerated chemiluminescence (ECL) method was proposed for the quantitation of 3-MeHis in urine by using an iridium(III) solvent complex ([Ir(dfppy)2(DMSO)Cl], dfppy = 2-(2,4-difluorophenyl)pyridine, Ir-DMSO) as a signal reagent. The photoluminescence (PL) and ECL responses of Ir-DMSO to 3-MeHis were studied. The ECL intensity of Ir-DMSO was enhanced in the presence of 3-MeHis because of the coordination recognition between Ir-DMSO and the imidazole group of 3-MeHis. Based on the enhancement of ECL intensity, 3-MeHis can be sensitively detected in the range of 5 to 25 µM. The detection limit was 0.4 µM. This is the first report of an ECL method for the quantitation of 3-MeHis. Further, to investigate the feasibility of the Ir-DMSO-based ECL method in practical applications, the developed ECL method was applied for 3-MeHis assay in urine samples of 28 healthy volunteers and 2 patients. The urine samples from patients hospitalized with obesity and kidney disease and healthy individuals were distinguished by the ECL responses of Ir-DMSO. The proposed ECL method based on the coordination recognition between iridium(III) solvent complex and the imidazole group of 3-MeHis allows inexpensive, fast, non-invasive, and sensitive detection of 3-MeHis in urine, which is promising for assessing large volumes of patients for routine analysis in clinical practices.

Rapid Determination of Positive-Negative Bacterial Infection Based on Micro-Hyperspectral Technology.

To meet the demand for rapid bacterial detection in clinical practice, this study proposed a joint determination model based on spectral database matching combined with a deep learning model for the determination of positive-negative bacterial infection in directly smeared urine samples. Based on a dataset of 8124 urine samples, a standard hyperspectral database of common bacteria and impurities was established. This database, combined with an automated single-target extraction, was used to perform spectral matching for single bacterial targets in directly smeared data. To address the multi-scale features and the need for the rapid analysis of directly smeared data, a multi-scale buffered convolutional neural network, MBNet, was introduced, which included three convolutional combination units and four buffer units to extract the spectral features of directly smeared data from different dimensions. The focus was on studying the differences in spectral features between positive and negative bacterial infection, as well as the temporal correlation between positive-negative determination and short-term cultivation. The experimental results demonstrate that the joint determination model achieved an accuracy of 97.29%, a Positive Predictive Value (PPV) of 97.17%, and a Negative Predictive Value (NPV) of 97.60% in the directly smeared urine dataset. This result outperformed the single MBNet model, indicating the effectiveness of the multi-scale buffered architecture for global and large-scale features of directly smeared data, as well as the high sensitivity of spectral database matching for single bacterial targets. The rapid determination solution of the whole process, which combines directly smeared sample preparation, joint determination model, and software analysis integration, can provide a preliminary report of bacterial infection within 10 min, and it is expected to become a powerful supplement to the existing technologies of rapid bacterial detection.

A Selective Fluorescent Nanoprobe Based on Graphene Quantum Dots and Hg2+ for the Determination of Tetracycline in Biological Samples.

A simple, sensitive, and selective fluorometric method based on graphene quantum dots and Hg2+ is presented for the determination of tetracycline. The fluorescence emission of graphene quantum dots at 463 nm decreased in the presence of Hg2+ ions due to its electrostatic interaction with the negatively charged surface of quantum dots at pH = 8.0. The addition of tetracycline to this system resulted in the retrieval of the fluorescence emission of the graphene quantum dots proportional to the tetracycline concentration. This is because of the interaction between tetracycline and Hg2+ that results in the release of the quantum dots' surface. Under the optimized conditions, the calibration curve indicated good linearity in the range of 2.0-44.0 nmol L-1 with a detection limit of 0.52 nmol L-1 for tetracycline. The designed nanoprobe was capable of the determination of tetracycline in serum and urine samples.

Magnetic solid-phase extraction of warfarin and gemfibrozil in biological samples using polydopamine-coated magnetic nanoparticles via core-shell nanostructure.

Herein, polydopamine-coated Fe3 O4 spheres were synthesized using a very simple, easy, cost-effective, efficient, and fast method. First, magnetic nanoparticles (Fe3 O4 ) were synthesized and were followed by accommodating polydopamine on the surface of the prepared Fe3 O4 . The prepared polydopamine-coated Fe3 O4 spheres were utilized as a sorbent in magnetic solid phase extraction of gemfibrozil and warfarin (as the model analytes). The extracted model analytes were desorbed by a suitable organic solvent and were analyzed by high-performance liquid chromatography. Under optimized condition, the linearity of the method was in the range of 0.1-200.0 µg/L for the selected analytes in water. The limits of detection were calculated to be in the range of 0.026-0.055 µg/L for warfarin and gemfibrozil, respectively. The limits of quantification were calculated to be in the range of 0.089-0.185 µg/L. The inter-day and intra-day relative standard deviations were determined to be in the range of 1.4%-3.3% in three concentrations in order to calculate the method precision. Furthermore, the enrichment factors were found to be 78 and 81 for warfarin and gemfibrozil, respectively. Moreover, the calculated absolute recoveries were between 78% and 81%. The obtained recoveries indicated that the method was useful and applicable in complicated real samples.

Reference standard analysis of multiple new and old plasma clearance models and renal clearance with special attention to measurement of reduced glomerular filtration rate.

Nine models were evaluated as candidate glomerular filtration rate (GFR) reference standards in three datasets using [51Cr(EDTA)]- or [169Yb(DTPA)]2- anions in 98 studies. Noncompartmental methods formed an upper limit for estimating mass excreted and voluntary urine collection formed a lower limit. For current models and methods, reduced GFR in adults resulted in inflated clearance estimates. Two different logarithmic models with exponential tails were created and may have underestimated reduced clearance. The logarithmic formulae can be used with only two plasma samples, and fit 13 multiple time-samples from 5 min to 24 h with an 8% standard deviation of residuals compared to 20% error for monoexponentials. For shorter times (4 or 5 h) the fit errors decreased but the ratio of errors remained at circa 2.5 times lesser for the logarithmic versus monoexponential models. Adaptively regularised gamma variate, Tk-GV, models that are well documented, but not in common use, were largely contained within the reference extreme values, were unbiased for different levels of clearance and were the only models to be uncorrelated to volume of distribution from mean residence time divided by weight. Using Tk-GV as a candidate reference standard, potentially better methods for routine clinical usage were discussed. Prospective clinical testing, and metabolic scaling of decreased renal function is advised for potential changes to patient triage.

Efficient Optosensing of Hippuric Acid in the Undiluted Human Urine with Hydrophilic "Turn-On"-Type Fluorescent Hollow Molecularly Imprinted Polymer Microparticles.

The development of complex biological sample-compatible fluorescent molecularly imprinted polymers (MIPs) with improved performances is highly important for their real-world bioanalytical and biomedical applications. Herein, we report on the first hydrophilic "turn-on"-type fluorescent hollow MIP microparticles capable of directly, highly selectively, and rapidly optosensing hippuric acid (HA) in the undiluted human urine samples. These fluorescent hollow MIP microparticles were readily obtained through first the synthesis of core-shell-corona-structured nitrobenzoxadiazole (NBD)-labeled hydrophilic fluorescent MIP microspheres by performing one-pot surface-initiated atom transfer radical polymerization on the preformed "living" silica particles and subsequent removal of their silica core via hydrofluoric acid etching. They showed "turn-on" fluorescence and high optosensing selectivity and sensitivity toward HA in the artificial urine (the limit of detection = 0.097 µM) as well as outstanding photostability and reusability. Particularly, they exhibited much more stable aqueous dispersion ability, significantly faster optosensing kinetics, and higher optosensing sensitivity than their solid counterparts. They were also directly used for quantifying HA in the undiluted human urine with good recoveries (96.0%-102.0%) and high accuracy (RSD ≤ 4.0%), even in the presence of several analogues of HA. Such fluorescent hollow MIP microparticles hold much promise for rapid and accurate HA detection in the clinical diagnostic field.

Concurrent Infection With Multiple Human Papillomavirus Types Among Unvaccinated and Vaccinated 17-Year-Old Norwegian Girls.

BACKGROUND: Whether type-specific human papillomavirus (HPV) infection influences the risk of acquiring infections with other HPV types is unclear. We studied concurrent HPV infections in 17-year-old girls from 2 birth cohorts; the first vaccine-eligible cohort in Norway and a prevaccination cohort. METHODS: Urine samples were collected and tested for 37 HPV genotypes. This study was restricted to unvaccinated girls from the prevaccination cohort (n = 5245) and vaccinated girls from the vaccine-eligible cohort (n = 4904). Risk of HPV infection was modelled using mixed-effect logistic regression. Expected frequencies of concurrent infection with each pairwise combination of the vaccine types and high-risk types (6/11/16/18/31/33/35/39/45/51/52/56/58/59) were compared to observed frequencies. RESULTS: Infection with multiple HPV types was more common among unvaccinated girls than vaccinated girls (9.2% vs 3.7%). HPV33 and HPV51 was the only HPV pair that was detected together more often than expected among both unvaccinated (P = .002) and vaccinated girls (P < .001). No HPV pairs were observed significantly less often than expected. CONCLUSIONS: HPV33 and HPV51 tended to be involved in coinfection among both unvaccinated and vaccinated girls. The introduction of HPV vaccination does not seem to have had an effect on the tendency of specific HPV types to cluster together.

The Two-Steps Reaction Fluorescent Probe for the Selective Detection of Cysteine and Its Applications.

We reported the specific fluorescent probe (MC-BOD-XDS) with two-steps reaction based on monosulfanyl-coumarin-BODIPY for selective detection of cysteine, high activity sulfanyl-coumarin as the multiple reaction group instead of a group internal standard fluorophore. The reaction mechanism of MC-BOD-XDS for detecting cysteine was different from the reported probes about the nucleophilic aromatic substitution reaction (SNAr) of chlorinated BODIPY. The fluorescent color of MC-BOD-XDS changed from yellow to red, and then to orange. The linear calibration diagram showed that it can potentially be used for quantitatively detection of Cys. Its potential applications were demonstrated by employing it for detection of Cys in artificial urine and in fluorescent imaging in HeLa cells.

Diagnostic utility of protein to creatinine ratio (P/C ratio) in spot urine sample within routine clinical practice.

The spot (random) urine protein to creatinine ratio (P/C ratio) is an alternative, fast and simple method of detecting and estimating the quantitative assessment of proteinuria. The aim of the work was to review the literature concerning the usefulness of spot urine P/C ratio evaluation in the diagnosis of proteinuria in the course of kidney disease, hypertension, gestational hypertension, preeclampsia, immunological diseases, diabetes mellitus, and multiple myeloma, and in the diagnosis of proteinuria in children. We searched the PubMed and Google Scholar databases using the following keywords: proteinuria, spot urine protein to creatinine ratio, spot urine P/C ratio, protein creatinine index, PCR (protein to creatinine ratio), P/C ratio and methods, Jaffe versus enzymatic creatinine methods, urine protein methods, spot urine protein to creatinine ratio versus ACR (albumin to creatinine ratio), proteinuria versus albuminuria, limitations of the P/C ratio. More weight was given to the articles published in the last 10-20 years. A spot urine P/C ratio >20 mg/mmol (0.2 mg/mg) is the most commonly reported cutoff value for detecting proteinuria, while a P/C ratio value >350 mg/mmol (3.5 mg/mg) confirms nephrotic proteinuria. The International Society for the Study of Hypertension in Pregnancy recommends a P/C ratio of 30 mg/mmol (0.3 mg/mg) for the classification of proteinuria in pregnant women at risk of preeclampsia. A high degree of correlation was observed between P/C ratio values and the protein concentration in 24-h urine collections. The spot urine P/C ratio is a quick and reliable test that can eliminate the need for a daily 24-h urine collection. However, in doubtful situations, it is still recommended to assess proteinuria in a 24-h urine collection. The literature review indicates the usefulness of the spot P/C ratio in various disease states; therefore, this test should be available in every laboratory. However, the challenge for the primary care physician is to know the limitations of the methods used to determine the protein and creatinine concentrations that are used to calculate the P/C ratio. Moreover, the P/C ratio cutoff used should be determined in individual laboratories because it depends on the patient population and the laboratory methodologies.

Spot urine samples to estimate 24-hour urinary calcium excretion in school-age children.

Urinary calcium/creatinine ratio (UCa/Cr) on a single spot urine sample is frequently used in children to evaluate calciuria, but its accuracy to estimate 24-h urinary calcium excretion (24hUCa) has not been properly assessed. We analyzed the correlation between UCa/Cr in various spot samples and 24hUCa among healthy children. A 24-h urine specimen and three spot urine samples (evening, first, and second morning) were collected in a convenience sample of children aged 6 to 16 years (n = 101). Measured 24hUCa was compared with UCa/Cr in each of the three spot samples. The ability of UCa/Cr to discriminate between children with and without hypercalciuria (calciuria > 4 mg/kg/24 h, 1 mmol/kg/24 h) and optimal timing of the spot sample were determined. Eighty-five children completed an adequate 24-h urine collection. Pearson correlation coefficients between the UCa/Cr on the spot sample and 24hUCa were 0.64, 0.71, and 0.52 for the evening, first, and second morning spot samples, respectively. Areas under the ROC curve were 0.90, 0.82, and 0.75, respectively, for the corresponding spot samples.Conclusion: The relatively strong correlation between 24hUCa and UCa/Cr in evening and first morning spot urine samples suggests that these spots could be preferred in clinical practice.Trial registration: ClinicalTrials.gov , NCT02900261, date of trial registration 14 September 2016. What is Known: •Urinary calcium/creatinine ratio on a single spot urine sample is frequently used as a proxy for 24-h urinary calcium excretion. •Correlation of these indicators, including the best timing for spot urine sampling, has not been properly assessed. What is New: •Relatively strong correlations were found between the calcium/creatinine ratio on a single spot urine sample and 24-h urinary calcium excretion in healthy children. •Evening and first morning spot samples had the highest correlation.

High daily salt intake had a negative impact on how well nocturnal enuresis treatment worked on children aged 7-10 years.

AIM: We investigated whether the daily salt intake of children with nocturnal enuresis influenced their response to 1-desamino-8-D-arginine vasopressin therapy. METHODS: This study comprised 129 children (67.4% boys) with a median age of 9.2 years (range 7.2-10.4) with monosymptomatic nocturnal enuresis who were seen at Kansai Medical University Hospital, Osaka, Japan, from 2013 to 2017. Urinary sodium concentrations were determined using a spot urine test, and the children were divided into appropriate (n = 55) and excessive salt intake (n = 74) groups based on Japanese Government guidelines. After a month of therapy, the treatment responses were compared for 39 and 50 children, respectively. RESULTS: There were no significant differences in the urea nitrogen-to-creatinine or calcium-to-creatinine ratios in the two groups. However, the excessive salt intake group showed a significantly reduced treatment response to the appropriate salt intake group. In addition, the excessive and appropriate salt intake groups showed median efficacy ratios of 8.2% and 21.8%, respectively, based on intention-to-treat analysis (P = 0.029) and 12.0% and 30.8% based on per-protocol analysis (P = 0.029). CONCLUSION: High daily salt intake significantly reduced the efficacy of ddavp therapy for nocturnal enuresis and consumption should be controlled during treatment.

A needle trap device packed with MIL-100(Fe) metal organic frameworks for efficient headspace sampling and analysis of urinary BTEXs.

The aim of this study was to develop a new method for the determination of benzene, toluene, ethylbenzene and xylene isomers (BTEXs) in urine samples. In this method, MIL-100(Fe)@Fe3 O4 @SiO2 metal-organic framework was synthesized, characterized and packed inside a needle trap device (NTD) as a sorbent for headspace extraction of unmetabolized BTEXs from urine samples followed by gas chromatography (GC) analysis. The GC device was equipped with a flame ionization detector (FID). The results showed that the optimal extraction time, extraction temperature and salt content were 60 min, 30°C and 5%, respectively. Also, the optimal desorption time and temperature were determined to be 1 min and 250°C, respectively. The limits of detection and quantification of the analytes of interest were in the ranges 0.0001-0.0005 and 0.0003-0.0014 µg ml-1 , respectively. The intra- and inter-day repeatability were <7.6%. The accuracy of the measurements in urine samples was in the range 7.1-11.4%. The results also demonstrated that the proposed NTD offered various advantages such as having high sensitivity and being inexpensive, reusable, user friendly, environmentally friendly and compatible for use with the GC device. Therefore, it can be efficiently used as a MIL-NTD for the extraction and analysis of unmetabolized BTEXs from urine samples.

Determination of urinary methylhippuric acids using MIL-53-NH2 (Al) metal-organic framework in microextraction by packed sorbent followed by HPLC-UV analysis.

For the analysis of methylhippuric acids (MHAs) in human urine samples, in this study, a new method based on the metal-organic framework (MOF) of MIL-53-NH2 (Al) in microextraction by packed sorbent (MEPS) was developed. The synthesis of MIL-53-NH2 (Al) was characterized by Fourier transform infrared spectra, field emission-scanning electron microscopy and X-ray diffraction. Response surface methodology was used to investigate the influences of several parameters including type and volume of elution, type of conditional solvent, sample volume and extraction cycle on MEPS efficiency. The results showed good recoveries (>94%) and excellent extraction efficiencies (>96%) at three different concentrations of 50, 500 and 1500 µg ml-1 (as low, mid and high concentrations, respectively) of MHA isomers. Calibration curves of MHAs were linear over the concentration range of 1-1500 µg ml-1 , with high correlation coefficients (r ≥ 0.998). The reproducibility of the proposed MIL-53-MEPS for determination of three isomers of MHA was found to be in the range of 3.5-11.1%. After optimization of the proposed technique, it was used to analyze MHAs in urine samples of workers exposed to xylenes in a petrochemical plant in Asalouyah, Iran. The results indicated that the MOF-MEPS method was selective, sensitive, rapid and efficient for the extraction of urinary MHAs. The technique is also environmentally friendly and inexpensive, and the MOF sorbent is reusable.

Boronic acid-modified polyhedral oligomeric silsesquioxanes on polydopamine-coated magnetized graphene oxide for selective and high-capacity extraction of the catecholamines epinephrine, dopamine and isoprenaline.

Amino-functionalized polyhedral oligomeric silsesquioxanes (POSS-8NH2) were covalently bound to the surface of polydopamine-coated magnetized graphene oxide. It was then reacted with 4-formylphenylboronic acid to prepare a "cubic boronic acid"-bonded magnetic graphene oxide adsorbent. The new adsorbent exhibits better selectivity and much higher adsorption capacity for ortho-phenols over adsorbents where small boronic ligands are directly bound to the surface of the material. It is shown to enable selective and faster enrichment of the catecholamines epinephrine (EP), dopamine (DA) and isoprenaline (IP) with high selectivity over many potential interferents that can occur in urine. The analytes were then quantified by HPLC with fluorometric detection. Under optimal conditions, response is linear (R2 ≥ 0.9907), limits of detection are low (0.54-2.3 ng·mL-1), and reproducibility is acceptable (inter- and intra-day assay RSDs of≤10.9%). The method was successfully applied to the determination of endogenous EP and DA and exogenous IP in urine samples. Graphical abstractSchematic of boronic acid (BA)-modified polyhedral oligomeric silsesquioxanes (POSS) on polydopamine-coated magnetized graphene oxide (magGO). The material (magGO@POSS-BA) has good selectivity and higher adsorption capacity to ortho-phenols and can be applied to enrich the catecholamines in urine.

Correlation between urinary fractionated metanephrines in 24-hour and spot urine samples for evaluating the therapeutic effect of metyrosine: a subanalysis of a multicenter, open-label phase I/II study.

We recently conducted an open-label phase I/II study to evaluate the efficacy and safety of preoperative and chronic treatment with metyrosine (an inhibitor of catecholamine synthesis) in pheochromocytoma/paraganglioma (PPGL) in Japan. We compared creatinine-corrected metanephrine fractions in spot urine and 24-hour urine samples (the current standard for the screening and diagnosis of PPGLs) from 16 patients to assess the therapeutic effect of metyrosine. Percent changes from baseline in urinary metanephrine (uMN) or normetanephrine (uNMN) were compared between spot and 24-hour urine samples. Mean percent changes in uMN or uNMN in spot and 24-hour urine were -26.36% and -29.27%, respectively. The difference in the percent change from baseline between uMN or uNMN in spot and 24-hour urine was small (-2.90%). The correlation coefficient was 0.87 for percent changes from baseline between uMN or uNMN measured in spot and 24-hour urine. The area under the receiver operator characteristic (ROC) curve of uMN or uNMN measured in spot urine vs. 24-hour urine (reference standard) to assess the efficacy of metyrosine treatment was 0.93. Correlations and ROCs between 24-hour urinary vanillylmandelic acid, adrenaline, and noradrenaline and 24-hour uMN or uNMN were similar to those between spot uMN or uNMN and 24-hour uMN or uNMN. No large difference was observed between spot and 24-hour urine for the assessment of metyrosine treatment by quantifying uMN or uNMN in Japanese patients with PPGLs. These results suggest that spot urine samples may be useful in assessing the therapeutic effect of metyrosine.

Application of simultaneous separation and derivatization for the determination of α-lipoic acid in urine samples by high-performance liquid chromatography with spectrofluorimetric detection.

To help to clarify therapeutic functions of lipoic acid (LA) in biochemical and clinical practice we have elaborated a fast, simple and accurate HPLC method enabling determination of LA in human urine. The proposed analytical approach includes reduction of LA with tris(2-carboxyethyl)phosphine and simultaneous separation and derivatization of the analyte with butylamine and o-phthaldialdehyde followed by spectrofluorimetric detection at λex = 340 nm and λem = 440 nm. The assay was performed using gradient elution and the mobile phase containing 0.0025 mol L-1 o-phthaldialdehyde in 0.0025 mol L-1 NaOH and acetonitrile. Linearity of the detector response for LA was observed in the range of 0.3-8 µmol L-1 . Limits of detection and quantification for LA in urine samples were 0.02 and 0.03 µmol L-1 , respectively. The total analysis time, including sample work-up, was <20 min. The analytical procedure was successfully applied to analysis of real urine samples delivered from six healthy volunteers who received a single 100 mg dose of LA.

Boronate affinity magnetic nanoparticles with hyperbranched polymer brushes for the adsorption of cis-diol biomolecules.

A boronate-modified magnetic affinity sorbent was prepared by adopting hyperbranched polyethyleneimine as the scaffold to amplify initiator sites. 3-Acrylamidophenylboronic acid was employed as monomer to proceed in situ free-radical polymerization on magnetite (Fe3O4) nanoparticles. Due to the improved density of boronic acid polymers, the adsorbent exhibited high adsorption capacity, typically (134 ± 8) µg mg-1 for dopamine, (92 ± 7) µg mg-1 for catechol, (363 ± 14) µg mg-1 for ovalbumin and (464 ± 22) µg mg-1 for horseradish peroxidase. These capacities are much higher than those of other adsorbents. The sorbent was applied to the enrichment of catecholamines from spiked human urine. Owing to the high adsorption capacity, only 1.0 mg of adsorbent was sufficient to eliminate the interferences and enrich the targets (dopamine, norepinephrine and epinephrine) within 5 min. They were quantified by HPLC. The recoveries from spiked samples range between 83.5% ~106%, with relative standard deviations of 3.2 ~ 9.4% (n = 5). The separation of glycoproteins from egg white was also accomplished prior to their analysis by PAGE. In the authors' perception, this approach is promising in that the density of functional groups on the adsorbent is strongly increased. Graphical abstract The preparation routine of boronate affinity magnetic adsorbent (Fe3O4@HpAAPBA). The adsorbent is used for the magnetic solid phase extraction of cis-dol compounds from real sample.

Superlattice stacking by hybridizing layered double hydroxide nanosheets with layers of reduced graphene oxide for electrochemical simultaneous determination of dopamine, uric acid and ascorbic acid.

A self-assembled periodic superlattice material was obtained by integrating positively charged semiconductive sheets of a Zn-NiAl layered double hydroxide (LDH) and negatively charged layers of reduced graphene oxide (rGO). The material was used to modify a glassy carbon electrode which then is shown to be a viable sensor for the diagnostic parameters dopamine (DA), uric acid (UA) and ascorbic acid (AA). The modified GCE displays excellent electrocatalytic activity towards these biomolecules. This is assumed to be due to the synergistic effects of (a) excellent interfacial electrical conductivity that is imparted by direct neighboring of conductive rGO to semiconductive channels of LDHs, (b) the superb intercalation feature of LDHs, and (c) the enlarged surface with an enormous number of active sites. The biosensor revealed outstanding electrochemical performances in terms of selectivity, sensitivity, and wide linear ranges. Typically operated at working potentials of -0.10, +0.13 and + 0.27 V vs. saturated calomel electrode, the lower detection limits for AA, DA and UA are 13.5 nM, 0.1 nM, and 0.9 nM, respectively, at a signal-to-noise ratio of 3. The sensor was applied to real-time tracking of dopamine efflux from live human nerve cells. Graphical abstract Schematic of the preparation of a superlattice self-assembled material by integrating positively charged semiconductive sheets of Zn-NiAl layered double hydroxide (LDH) with negatively charged reduced graphene oxide (rGO) layers. It was applied to simultaneous electrochemical detection of dopamine (DA), uric acid and ascorbic acid.

Rapid and sensitive determination of nine bisphenol analogues, three amphenicol antibiotics, and six phthalate metabolites in human urine samples using UHPLC-MS/MS.

Bisphenol analogues, amphenicol antibiotics, and phthalate have widely aroused public concerns due to their adverse effects on human health. In this study, a rapid and sensitive method for determination of nine bisphenol analogues, three amphenicol antibiotics, and six phthalate metabolites in the urine based on ultra-high-performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry was developed and validated. The sample pretreatment condition on the base of mixed-mode anion-exchange (Oasis MAX) SPE was optimized to separate bisphenol analogues and amphenicol antibiotics from phthalate metabolites: the former were detected with a mobile phase of 0.1% ammonium water solution/methanol containing 0.1% ammonium water solution in negative mode, whereas the latter were determined with a mobile phase of 0.1% acetic acid solution/acetonitrile containing 0.1% acetic acid in negative mode. The limits of detection were less than 0.26 ng/mL for bisphenol analogues, 0.12 ng/mL for amphenicol antibiotics, and 0.14 ng/mL for phathalate metabolites. The recoveries of all target analytes in three fortification levels ranged from 72.02 to 117.64% with the relative standard deviations of no larger than 14.51%. The matrix effect was adjusted by isotopically labeled internal standards. This proposed method was successfully applied to analyze 40 actual urines and 13 out of 18 studied compounds were detected. Graphical abstract Simultaneous determination of nine bisphenol analogues, three amphenicol antibiotics, and six phthalate metabolites in human urine samples.