[The method of determination for 2, 3-Butanedione in the air of workplace by high performance liquid chromatography with derivatization].

Objective: To establish a method for the determination of 2, 3-Butanedione (BUT) in the air of workplace, which including the process of collection by absorption in phosphoric acid aqueous solution and the process of analysis and detection by high performance liquid chromatography with derivatization. Methods: In October 2022, a porous glass plate absorption tube containing 10 ml of 0.01% phosphoric acid solution was used to collect BUT in the air of the workplace at a flow rate of 0.2 L/min. The absorption solution was derived by 2, 4-dinitrophenylhydrazine for 75 min and separated on a SB-C18 column (250 mm×4.6 mm, 5 µm) . At the column temperature of 30 ℃, the mixture of acetonitrile-water (V∶V, 1∶1) was eluted at the flow rate of 1.0 ml/min. It was detected by UV detector (λ=365 nm) , qualitatived by retention time and quantitatived by external standard. Results: It showed that BUT in phosphoric acid aqueous solution could be stored for at least 7 d at 4 ℃. There was a linear relationship within the determination range of 0.05-6.00 µg/ml, the linear regression equation was y=89.610x+0.133, r=0.9999. The sampling absorption efficiencies were 98.33%-100.00%, the detection limit of the method was 0.005 µg/ml, the minimum detection concentration was 0.016 mg/m(3) (based on V(0)=3.0 L) . The recovery rates were 95.96%-102.44%, the intra batch precision were 4.36%-7.78%, and the inter batch precision were 4.96%-6.06%. Conclusion: The method has the advantages of simple operation, high sensitivity and good accuracy. It can prevent the loss and degradation of BUT. It can be used for the determination of BUT in the air of workplace.

Formulating an altered dentin substrate to improve dentin bonding.

STATEMENT OF PROBLEM: Secondary caries is a major factor in the failure of dental restorations. However, studies on the fabrication of acid-resistant and antibacterial dentin to improve dentin bonding are sparse. PURPOSE: The purpose of this in vitro study was to compare the effects of 2 types of fluoride-containing etchants on dentin bonding and explore the feasibility of formulating an altered dentin substrate to improve dentin bonding. MATERIAL AND METHODS: NaF-containing and SnF2-containing etchants were developed by adding sodium fluoride and stannous fluoride to a 35% phosphoric acid aqueous solution. Two groups (N1 and N2) containing NaF, 10 and 30 mg/mL respectively, and 2 groups (S1 and S2) containing SnF2, 18.6 and 55.8 mg/mL respectively, were formulated. The etchant of the control group (C) was 35% phosphoric acid gel. Scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), Fourier transform infrared spectroscopy (FTIR), microhardness, antierosion, and antibacterial tests were performed on the treated dentin. Moreover, the microtensile bond strength (µTBS) of each group was tested, and the fracture mode was determined after testing. Statistical analysis was performed with the 2-way ANOVA test (α=.05). RESULTS: The exposed collagen fiber was observed in group C, and minerals were formed on the dentin in the experimental groups. SEM, FTIR, and the microhardness test indicated more remineralization in the SnF2-containing etchant groups. The µTBS of S1 (77.5 ±10.36 MPa) was the highest in all groups, and group C (38.5 ±9.01 MPa) was the lowest. Moreover, the antierosion and antibacterial properties of the S2 group were the best among all groups (P<.05). CONCLUSIONS: Compared with NaF-containing etchant, SnF2-containing etchant could improve the dentin substrate, increase remineralization, improve bonding strength, and enhance antibacterial ability, especially by increasing resistance to acid erosion.

Exploration of highly selective fluorogenic 'on-off' chemosensor for H2 PO4 - ions: ICT-based sensing and ATPase activity profiling.

In this study, the recognition contour of Chemosensor 1 was investigated using semiaqueous methanol (XH , mole fraction = 0.31) for a range of anions and bioactive species. Host-receptor signalling based on the internal charge transfer mechanism for Chemosensor 1 was explored and reported. Structure of Chemosensor 1 and its plausible anion coordination based on hydrogen bonding is complemented with density functional theory. Consequently, we investigated the applicability of the synthesized probe in blood plasma, urine, tap water samples, and for monitoring of ATP in lysosomes by apyrase enzyme.

Sequencing of Phosphoramidate Oligonucleotides by Acid Hydrolysis and Mass Spectrometry.

Hydrolysis of N3'-P5' phosphoramidate and thiophosphoramidate oligonucleotides with 0.1% formic acid leads to the cleavage of the 3' N-P bond and generates two products, one of which contains a 5'-phosphate. Analysis of the hydrolytic products by liquid chromatography, coupled with mass spectrometry, reveals the mass ladder from both termini, which is used to determine the sequence. While acid hydrolysis does not result in depurination, internal fragments especially in the low mass range are detected. The method is applied to DNA and RNA analogues with and without modifications at the 2'-position. This approach enables rapid sequence confirmation of synthetic phosphoramidate oligonucleotides for quality control as well as denovo sequencing.

Phosphoric acid and phosphorylation levels are potential biomarkers indicating developmental competence of matured oocytes.

Here, we aimed to identify biomarkers for mice oocyte maturation in metaphase II in vivo and in situ using Raman spectroscopy. Principal component analysis of 324 Raman data points of oocytes at Phase I, II, III, and IV showed that the phosphoric acid concentration uniformly increased in oocytes with higher developmental competence than in oocytes at other maturation stages, and proteins were more phosphorylated. The maturation phases were successfully predicted by linear discriminant analysis with high accuracy (90.7%) using phosphoric molecular information mentioned above. Furthermore, detections of higher concentration of unsaturated fatty acids in overmatured oocytes indicated that a decline in metabolic activity due to overmaturation induced a surplus of these lipid components. Upon assessing invasiveness by laser irradiation, about 50% irradiated oocytes progressed to morula and blastocyst stages in good conditions. Thus, Raman spectroscopy holds promise in evaluating oocyte maturation and quality based on molecular information in infertility treatment.

Quantitative imaging of 33P in plant materials using 14C polymer references.

Phosphorus (P) research still lacks techniques for rapid imaging of P use and allocation in different soil, sediment, and biological systems in a quantitative manner. In this study, we describe a time-saving and cost-efficient digital autoradiographic method for in situ quantitative imaging of 33P radioisotopes in plant materials. Our method combines autoradiography of the radiotracer applications with additions of commercially available 14C polymer references to obtain 33P activities in a quantitative manner up to 2000 Bq cm-2. Our data show that linear standard regressions for both radioisotopes are obtained, allowing the establishment of photostimulated luminescence equivalence between both radioisotopes with a factor of 9.73. Validating experiments revealed a good agreement between the calculated and applied 33P activity (R2 = 0.96). This finding was also valid for the co-exposure of 14C polymer references and 33P radioisotope specific activities in excised plant leaves for both maize (R2 = 0.99) and wheat (R2 = 0.99). The outlined autoradiographic quantification procedure retrieved 100% ± 12% of the 33P activity in the plant leaves, irrespective of plant tissue density. The simplicity of this methodology opens up new perspectives for fast quantitative imaging of 33P in biological systems and likely, thus, also for other environmental compartments.

Nutrient enrichment during shrimp cultivation alters bacterioplankton assemblies and destroys community stability.

Intensive shrimp farming is generally accompanied by nutrient enrichment and gradual eutrophication, which impose major threats to shrimp culture ecosystems. However, little is known about how the bacterioplankton community in a rearing environment responds to increased eutrophication during shrimp culture processes. In this study, we used the MiSeq sequencing technique to explore the impacts of nutrient enrichment on the assembly and stability of the bacterioplankton community. Our results showed that magnitudes of the changes in the bacterioplankton community compositions (BCCs) and diversity were closely associated with eutrophication level. Moreover, a phylogenetic-based mean nearest taxon distance (MNTD) analysis revealed that increased eutrophication significantly (P < 0.01) changed the bacterioplankton ecological processes from deterministic to stochastic. A structural equation model showed that eutrophication indicators affected the BCCs either directly by controlling resources or indirectly by modifying other environmental variables of the shrimp ponds in complex pathways. Furthermore, association network comparisons revealed that nutrient enrichment increased the complexity of interspecies interactions and the proportion of cooperative interactions and decreased the proportion of generalists, which suggest that nutrient enrichment destroyed the community stability. These findings suggest that minimizing nutrient pollution, especially at the end of cultivation, could be an important management tool for establishing a microbially mature water system.

Determination of nucleoside triphosphatase activities from measurement of true inorganic phosphate in the presence of labile phosphate compounds.

One of the most common assays for nucleoside triphosphatase (NTPase) activity entails the quantification of inorganic phosphate (Pi) as a colored phosphomolybdate complex at low pH. While this assay is very sensitive, it is not selective for Pi in the presence of labile organic phosphate compounds (OPCs). Since NTPase activity assays typically require a large excess of OPCs, such as nucleotides, selectivity for Pi in the presence of OPCs is often critical in evaluating enzyme activity. Here we present an improved method for the measurement of enzymatic nucleotide hydrolysis as Pi released, which achieves selectivity for Pi in the presence of OPCs while also avoiding the costs and hazards inherent in other methods for measuring nucleotide hydrolysis. We apply this method to the measurement of ATP hydrolysis by nitrogenase and GTP hydrolysis by elongation factor G (EF-G) in order to demonstrate the broad applicability of our method for the determination of nucleotide hydrolysis in the presence of interfering OPCs.

[Mineral composition of mixed saliva in patients with dental fluorosis]. / Mineral'nyi sostav smeshannoi sliuny u patsientov s fliuorozom zubov.

The aim of the study was to assess the mineral composition of mixed saliva in dental fluorosis patients undergoing treatment with microabrasion and bleaching. The study included 60 patients aged 18-35 years with various forms of dental fluorosis. Group 1 included 40 patients in which enamel microabrasion was performed, group 2 - 20 patients with microabrasion and bleaching. Mixed saliva composition was analyzed with Olimpus automatic analyzing device. Dental fluorosis treatment in both groups resulted in saliva mineral composition changed associated with enamel demineralization which proves the necessity for calcium and phosphate containing compositions in these treatment groups.

[An unusual bodily injury]. / Eine ungewöhnliche Körperverletzung.

In most cases, bodily harm results from the use of sharp objects or blunt force. This paper deals with a 42-year-old pharmacist who was known to the police and the courts because of several previous convictions for bodily injury. The man had visited a pub just before it closed and was therefore not served any drinks. He got angry about this and returned to his pharmacy (within walking distance) to fetch three disposable syringes which he filled with phosphoric acid (85%). Through the open pub window, he splattered the acid from the syringes on two guests and the host, who were hit on the upper part of their bodies and the arms. All the victims developed dermal alterations such as focal erythema and small blisters (pemphigus-like efflorescences, as already described by Weyrich). At first, the pharmacist denied the use of phosphoric acid and claimed to have used a mixture of urine and water. Examinations of spots on the still unwashed clothes revealed very low pH-values (ca. 2.0; pH-Indicator-Stripes, Merck; Medi-Test, Machery & Nagel). Tests for substances typical of urine produced completely negative results. However, very high phosphate concentrations were found on the spots in question. Thus, the probability that the pharmacist had used phosphoric acid to commit the offence was very high. The pharmacist was sentenced to one year and two months' imprisonment for dangerous bodily harm according to Section 224 German Criminal Code. In accordance with the law, phosphoric acid was classified as "poison", for which application on the skin is sufficient.

Isotopic Fingerprint for Phosphorus in Drinking Water Supplies.

Phosphate dosing of drinking water supplies, coupled with leakage from distribution networks, represents a significant input of phosphorus to the environment. The oxygen isotope composition of phosphate (δ(18)OPO4), a novel stable isotope tracer for phosphorus, offers new opportunities to understand the importance of phosphorus derived from sources such as drinking water. We report the first assessment of δ(18)OPO4 within drinking water supplies. A total of 40 samples from phosphate-dosed distribution networks were analyzed from across England and Wales. In addition, samples of the source orthophosphoric acid used for dosing were also analyzed. Two distinct isotopic signatures for drinking water were identified (average = +13.2 or +19.7‰), primarily determined by δ(18)OPO4 of the source acid (average = +12.4 or +19.7‰). Dependent upon the source acid used, drinking water δ(18)OPO4 appears isotopically distinct from a number of other phosphorus sources. Isotopic offsets from the source acid ranging from -0.9 to +2.8‰ were observed. There was little evidence that equilibrium isotope fractionation dominated within the networks, with offsets from temperature-dependent equilibrium ranging from -4.8 to +4.2‰. While partial equilibrium fractionation may have occurred, kinetic effects associated with microbial uptake of phosphorus or abiotic sorption and dissolution reactions may also contribute to δ(18)OPO4 within drinking water supplies.

High-performance organic nanomembrane based sensors for rapid in situ acid detection.

Here, we demonstrate the fabrication, characterization, and tailoring of porous organic nanomembranes and their direct integration on inorganic substrates for sensing applications. The chemically prepared nanomembranes can be integrated on both conducting and insulating substrates by either transfer or direct synthesis. We also successfully demonstrate their use for the detection of commonly used acids including HCl, H(2)SO(4), or H(3)PO(4) and their respective counterions, chlorides, sulfates, and phosphates. Impressively, the in situ acid detection is achieved down to 5 nmol·L(-1), while the quantification is feasible between 5 µmol·L(-1) and 10 mmol·L(-1). These values are among the lowest values reported so far in literature. Furthermore, the organic nanomembrane based sensor covers a wide concentration range of almost 8 orders of magnitude including the environmental limits currently adopted.

Radionuclide concentrations in raw and purified phosphoric acids from Brazil and their processing wastes: implications for radiation exposures.

Radionuclides from the U and Th natural series are present in alkaline rocks, which are used as feedstock in Brazil for the production of raw phosphoric acid, which can be considered as a NORM (naturally occurring radioactive material). As a result of the purification of raw phosphoric acid to food-grade phosphoric acid, two by-products are generated, i.e., solid and liquid wastes. Taking this into account, the main aim of this study was to evaluate the fluxes of natural radionuclide in the production of food-grade phosphoric acids in Brazil, to determine the radiological impact caused by ingestion of food-grade phosphoric acid, and to evaluate the solid waste environmental hazards caused by its application in crop soils. Radiological characterization of raw phosphoric acid, food-grade phosphoric acid, solid waste, and liquid waste was performed by alpha and gamma spectrometry. The (238)U, (234)U, (226)Ra, and (232)Th activity concentrations varied depending on the source of raw phosphoric acid. Decreasing radionuclides activity concentrations in raw phosphoric acids used by the producer of the purified phosphoric acid were observed as follows: Tapira (raw phosphoric acid D) > Catalão (raw phosphoric acids B and C) > Cajati (raw phosphoric acid A). The industrial purification process produces a reduction in radionuclide activity concentrations in food-grade phosphoric acid in relation to raw phosphoric acid produced in plant D and single raw phosphoric acid used in recent years. The most common use of food-grade phosphoric acid is in cola soft drinks, with an average consumption in Brazil of 72 l per person per year. Each liter of cola soft drink contains 0.5 ml of food-grade phosphoric acid, which gives an annual average intake of 36 ml of food-grade phosphoric acid per person. Under these conditions, radionuclide intake through consumption of food-grade phosphoric acid per year per person via cola soft drinks is not hazardous to human health in Brazil. Considering these annual additions of (238)U, (226)Ra, (232)Th and (40)K, and since these radionuclide should be homogeneously distributed in the upper 10 cm of soils with an assumed apparent density of 1.5 g/cm(3), a maximum increase of 0.19 ± 0.03 Bq kg(-1) of soil is expected for (238)U and (234)U. Thus, the addition of solid waste as phosphate fertilizers to Brazilian agricultural soils does not represent a hazard to the ecosystem or to human health.

Ratiometric fluorescent receptors for both Zn2+ and H2PO4(-) ions based on a pyrenyl-linked triazole-modified homooxacalix[3]arene: a potential molecular traffic signal with an R-S latch logic circuit.

A ratiometric fluorescent receptor with a C(3) symmetric structure based on a pyrene-linked triazole-modified homooxacalix[3]arene (L) was synthesized and characterized. This system exhibited an interesting ratiometric detection signal output for targeting cations and anions through switching the excimer emission of pyrene from the "on-off" to the "off-on" type in neutral solution. (1)H NMR titration results suggested that the Zn(2+) center of receptor L·Zn(2+) provided an excellent pathway of organizing anion binding groups for optimal host-guest interactions. It is thus believed that this receptor has potential application in sensing, detection, and recognition of both Zn(2+) and H(2)PO(4)(-) ions with different optical signals. In addition, the fluorescence emission changes by the inputs of Zn(2+) and H(2)PO(4)(-) ions can be viewed as a combinational R-S latch logic circuit at the molecular level.

A simple and neutral receptor acting as a sensitive and switch-on fluorescent chemosensor for H2PO4(-).

A novel artificial anion chemosensor 1 based on 2,2'-di(4-nitrophenylurea-ß-N-yl)-1, 1'-binaphthyl is designed and synthesized for sensing anions including halide ions and oxoanions. The fluorescent emission of the binaphthyl of receptor 1, forming the hydrogen bonding with anions as the sensing mechanism, is monitored in DMSO for detecting anions. In brief, while most of the anion chemosensors are switch-off fluorescent chemosensor, or non-fluorescent sensor, receptor 1 exhibits obviously the switch-on emission during the complexation with H(2)PO(4)(-).

[Determination of phosphoric acid in the air of workplace by ion chromatography].

OBJECTIVE: To develop a method to determine phosphoric acid in the air of workplace by ion chromatography. METHODS: Phosphoric acid was collected by millipore filter and washed by deionized water then detected by ion chromatography. RESULTS: Linearity range of test was 0 ∼ 20 µg/ml, relative standard deviation (RSD) was 1.95% ∼ 3.31%, the elution efficiency was 103.0% ∼ 109.6%, determination limit was 0.1 µg/ml (when sample size was 20.01) concentration limit was 0.01 mg/m(3) (when the collected air was 75 L). CONCLUSION: This method is convenient for air collection, simple, with high sensitivity and good precision, is a good method for determination of phosphoric acid in the air of workplace.

Chromametric and spectroscopic determinations of natural organic matter in water and caffeine/phosphoric acid-containing soft drink using grape (V. vinifera) extract.

Natural anthocyanin dyes are safe for human and the environment due to their biocompatibility and rapid biodegradability. In this paper, an aqueous anthocyanin extract from grapes was used as a colouring reagent for the determination of humic acid (a cancer-promoting agent) in water and caffeine/phosphoric acid-containing caramelized soft drink. Three techniques, viz: chromametry, ultraviolet-visible spectrophotometry (UV-Vis) and Fourier transform infrared spectroscopy (FTIR) were employed for comparative quantifications. The results showed that the chromametry technique exhibited better sensing performance than the spectroscopic techniques in terms of the limit of detection (LOD) and % recovery. However, both chromametry and UV-Vis techniques agreed that the presence of HA could easily be detected in the soft drink at a spiked concentration of 6.4 ppm where less interference occurred.

Azobenzene-based system for fluorimetric sensing of H(2)PO(4)(-) (Pi) that works as a molecular keypad lock.

A 'novel' and cost-effective 'on-off'-type monophosphate H(2)PO(4)(-) (Pi) chemosensor based on the mononuclear 2,2'-dihydroxyazobenzene (DHAB)-Zn(ii) complex was developed and a molecular keypad lock can be realized in the DHAB-based system by using Zn(ii) cations and Pi anions as inputs.

Rapid analysis of alkylphosphonate drugs by capillary zone electrophoresis using indirect ultraviolet detection.

A rapid capillary electrophoretic method for the analysis of three alkylphosphonate drugs (i.e. fosfomycin disodium (FOS), clodronate disodium (CLO) and alendronate sodium (ALN)) was developed by using multiple probe BGE and indirect UV detection. BGE containing 30 mM benzoic acid, 5 mM salicylic acid and 0.5 mM CTAB (pH 3.8), temperature of 30 degrees C, applied voltage of -30 kV and detection at 220 nm provided baseline separation of all analytes (resolution (R)>2.2) in 3.2 min. EOF reversal by addition of CTAB and negative voltage polarity leading to the co-EOF flow and short analysis time. Two probe BGE greatly improved peak symmetry. The method showed good linearity (r(2)>0.999 in ranges of 20-1000 microg/mL for FOS, 100-1000 microg/mL for CLO and 100-750 microg/mL for ALN) repeatablitiy (RSD<2.15%), recovery (99.3-101.1%) and sensitivity (LOD<50 microg/mL). Freshly prepared BGE and sample solutions are essential for the method precision and accuracy. This new method can be utilized for routine analysis of FOS, CLO and ALN in dosage forms because of its efficiency, reliability, speed and simplicity.

Environmental benefits of using magnesium carbonate minerals as new wildfire retardants instead of commercially available, phosphate-based compounds.

A serial batch leaching experiment has been carried out to evaluate the release of elements from the ash of Pinus halepensis needles burned under two test conditions-with and without treatment of the forest species with the carbonate minerals (huntite and hydromagnesite) in aqueous solution (pH 6). The ash (before and after leaching) and leachates were analyzed using atomic absorption spectroscopy and X-ray diffraction. Compared with data from samples treated with the commercially available, phosphate-based fire retardant diammonium phosphate (DAP), we found that use of huntite or hydromagnesite was much more successful in obstructing the release of the toxic elements present in the ash, probably because of the alkaline conditions resulting from decomposition of the minerals during burning. In contrast, DAP tended to be more able to facilitate the extraction of some toxic metals (e.g., Zn, Cu, Mn), probably because of the acidic conditions resulting from its decomposition to phosphoric acid. Data from this study thus lend strong support to the use of magnesium carbonate minerals as new wildfire retardants, because they were shown to be more friendly to the environment (e.g., soil, ground, and underground water streams) than those currently in use (e.g., phosphate or sulfate salt type).