Naphthalenedisulfonic Acid Research Articles

Preparation of a class of cucurbit[6]uril-light rare-earth-based supramolecular assemblies and its efficient detection of chloramphenicol

By introducing 4,4′-naphthalenedisulfonic acid (4,4′-H2BPs) as a structure-induced agent, four novel cucurbit[6]uril-based supramolecular assemblies have been successfully prepared in the cucurbit[6]uril (Q[6]) system with light rare-earth elements (La3+, Ce3+, Pr3+, Nd3+) under hydrothermal conditions. Crystal structure analysis shows that the assemblies 1 (La3+), 2 (Ce3+), 3 (Pr3+) are isomorphism 3D frameworks, where Q[6] can directly coordinate with light rare-earth metal ions to form 1D −Ln(III)- Q[6]-Ln(III)- chains, while the 4 (Nd3+) presents 3D structures stacking by the unit of Q[6]@Nd3+@Q[6]@Nd3+@Q[6], respectively. In these structures, 4,4′-H2BPs ligands all can act as an organic counter anion and bridging via the outer-surface interaction of cucurbit[n]uril (OSIQ) in the system, which is the main driving force from low-dimensional to high-dimensional. Meanwhile, the fluorescence sensing performance of the two assemblies for antibiotics was investigated, and the results showed that assembly 1 could be used as a promising fluorescent sensor material to detect chloramphenicol (CAP).

UiO-66 membranes with confined naphthalene disulfonic acid for selective monovalent ion separation

The selective separation of monovalent ions remains a challenge because of the similar sub-nanometer sizes. Metal-organic frameworks (MOFs) are promising candidate membranes for ion selective separation based on the angstrom sized windows for size sieving. Here, to further enhance the monovalent ion selectivity, 1, 5-naphthalenedisulfonic acid tetrahydrate (NTDS) molecules with sulfonate groups are incorporated to offer a binding affinity, generating a UiO-66@NTDS membrane via the window-cavity structure confinement. In addition to the size sieving effect, the charge and affinity interaction can compensate the energy loss induced by the ion dehydration. Thus, the UiO-66@NTDS membranes exhibit elevated separation performance compared to the original UiO-66 membranes under the concentration gradient driven, accompanied by high monovalent cation permeation rates (i.e., 0.3–0.7 mol m−2 h−1) and mono-/divalent cation selectivities (i.e., ∼73 for K+/Mg2+, ∼57 for Na+/Mg2+, and ∼46 for Li+/Mg2+). This work provides guidelines for the development of efficient ion-selective MOF membranes via the combination of size sieving and interaction attraction.

Optimasi Adsorpsi Ion Tembaga (II) Menggunakan Silika Gel-GPTMS Termodifikasi Sulfonat

Adsorption is a process of sorption onto a specific substance that occurs at the surface of a solid material due to intermolecular forces or the penetration of a substance into the solid material surface. Adsorption involves an adsorbent as the sorbent material and an adsorbate as the component being sorbed. Silica gel is a commonly employed adsorbent for the sorption of Cu2+ ions. It is utilized as an adsorbent due to the presence of silanol and siloxane groups, which serve as active sites that can be modified. The modification aims to enhance the adsorption capacity of silica gel for Cu2+ metal ions. In aquatic environments, Cu metal ions are highly toxic to living organisms, posing significant hazards. The modifying compound employed in this study is monosodium salt of 4 – amino – 5 – hydorxy – 2,7 – naphthalenedisulfonic acid. However, prior to the sulfonate compound modification, a linking compound, γ-glycidoxypropyltrimethoxysilane (GPTMS), is required. The purpose of this study was to determine the effect of variations in pH and contact time on the adsorption of Cu2+ metal ions on sulfonate modified silica gel – GPTMS. The modified silica gel was characterized using Fourier-transform infrared (FTIR). The adsorption of Cu2+ ions was characterized by specific surface area (SSA), and the optimal adsorption conditions were determined as pH 4 and contact time of 60 minutes.

CORROSION RESISTANCE OF ZINC GALVANIC DEPOSITS OBTAINED BY THE ELECTROCHEMICAL 3D PRINTING METHOD

The article is devoted to the implementation of the process of electrochemical 3D printing of zinc products and the determination of the effect of the methodof their production on corrosion resistance. The possibility of electrochemical 3D printing of zinc objects with a fine-crystalline compact structure using high-speed sulfate plating electrolyte has been shown. The most resilient and elastic zinc depositswere obtained in the electrolyte without the addition of organic additives and when gelatin was added to the electrolyte. The use of naphthalene disulfonic acid of 1,5-disodium salt made it possible to obtain the most finely crystalline and semi-glossy zinc deposits, but the fragility of the deposits increased somewhat. Conducted studies of the corrosion resistance of printed zinc objects showed that the use of electrochemical 3D printing as a method of obtaining and introducing organic additives into the electrolyte does not lead to a decrease in the corrosion resistance of the metal

The Effect of Organic Acid Dopants on the Specific Capacitance of Electrodeposited Polypyrrole-Carbon Nanotube/Polyimide Composite Electrodes

Energy storage materials are constantly being improved and developed to cope with the ever-increasing demand of the electronic devices industry. Various synthetic approaches have been used to manufacture electrode materials. This paper is focused on the use of intrinsically conductive polymers such as polypyrrole (PPy) in the development of single-walled carbon nanotube-polyimide, SWCNT-PI, supercapacitor electrode materials. The polypyrrole used in the study is doped with different organic acid dopants of various sizes, including styrene sulfonic acid, SSA, toluene sulfonic acid, TSA, dodecylbenzene sulfonic acid, DBSA, naphthalene disulfonic acid, NDSA, and naphthalene trisulfonic acid, NTSA. The number of sulfonic acid functional group per dopant molecule varied from one to three, while the number of benzene rings in the aromatic unit varied from one to two. It is believed that, as the sulfonic acid to the dopant molecule ratio changes, the morphology and electrochemical properties of the doped PPy-coated electrode material will change accordingly. The change in the morphology of the doped PPy, due to the respective dopant, is correlated with the change in the electrochemical properties of the modified composite electrode. The naphthalene trisulfonic acid (NTSA) dopant was found to produce the highest specific capacitance of about 119 F/g at 5 mV/s. Furthermore, the NTSA-doped PPy electrode system showed the highest porosity and highest tan delta damping peak height for the a-transition. The styrene sulfonic acid-doped PPy/SWCNT-PI electrode material showed an impressive storage modulus of more than 2 GPa, but lower porosity. Styrene polymerization is believed to have occurred. The results obtained indicate that the porosity and electrochemical properties of the electrode materials are correlated.

Hetero-Aggregation-Induced Tunable Emission in Multicomponent Crystals

Crystal engineering is a green and convenient approach to designing desirable materials through rational manipulation of intermolecular interactions. We have reported the lesser reported sulfonate–pyridinium intermolecular interaction for the design and synthesis of organic co-crystals with improved features. Here in we report the utilization of the interaction to tune the solid-state luminescence of organic precursor naphthalene disulfonic acid (NDSA-2H). Organic salts of NDSA-2H are synthesized and characterized with three isostructural bipyridyl co-formers: 4-phenylpyridine (4-PhPy), 2-phenylpyridine (2-PhPy) and 2,2′-bipyridine (2,2-bpy). Structural investigation validates aggregation of organic acid and base co-formers through sulfonate–pyridinium synthon and proton transfer between them. Compared to NDSA-2H, the molecular salts [(4-PhPy-H)2+(NDSA)2–·2H2O] (1) and [(2,2-BPY-2H)2+(NDSA)2–] (3) undergo a blue and red shift, respectively, while solid-state emission of [(2-PhPy-H)2+(NDSA)2–] (2) remains unaltered. This solid-state emission tuning is attributed to the different modes of crystal packing and arises from monomer emissions in 1 and 2 and excimer emission in 3. 3 also exhibits a relatively longer lifetime of 20.7 ns while 2 exhibits better quantum yields (ϕ = 22.7). Solution-phase photophysical behavior has been investigated for representative co-crystal system 3, after validation of its solution-phase integrity. 3 undergoes a hetero-aggregation-induced tunable emission (HAITE) phenomenon in the water–acetone system to exhibit maximum emission intensity at 90% volume fraction of acetone, which is further validated by the diffuse light scattering (DLS) and scanning electron microscopy (SEM) studies. 3 also exhibits solvatochromism in terms of emission intensity change with the nature of the solvent, being brightest in methanol (ϕ = 29.3) and very dim in water (ϕ = 10.1).

Decoupling electrochemical parameters of molecular-level-controlled polypyrrole and graphene oxide nanocomposite

A molecular-level-controlled polypyrrole from a predoped two-monomer-connected precursor (TMCP) and graphene oxide (GO) nanocomposite is synthesized for an active electrode. TMCP (Py:NDSA:Py) consists of two pyrrole monomer, in which bifunctional naphthalene disulfonic acid (NDSA) acts as a protonic dopant and connector. Four molecular-level-controlled P(Py:NDSA:Py)/GO-based nanocomposites are formed when Py:NDSA:Py is polymerized on the hydrophilic GO surface with 100, 75, 50, and 25 mol % of NDSA. The resulting P(Py:NDSA100:Py)/GO nanocomposite exhibits excellent electrochemical performance and cycling stability. A systematic investigations of molecular-level-controlled P(Py:NDSA100:Py)/GO nanocomposite shows that various parameters such as relatively high crystallinity (47.2 %), crystalline domain size (24.2 nm), high doping level (35 %), and electrical conductivity (23.6 S/cm) could be well controlled using a 100 mol % of NDSA connector. An optimized P(Py:NDSA100:Py)/GO nanocomposite with 20 wt% GO significantly improves the specific capacitance of 306 F g−1 at a current density of 1 A g−1 and excellent cycling stability of 75 % up to 2000 cycles without using carbon supplement (carbon black). This systematic decoupling of electrochemical parameters of molecular-level-controlled polypyrrole nanocomposites can serve as an approach for rational design with tailored properties of other polymeric nanocomposites for electrochemical applications.

Rapid adsorption of acid dyes using Cu(II) thiourea modified cellulose complex.

In the present work, the acid dyes namely, eriochrome cyanine R (ECR) and 2-(4-Sulfo phenyl azo)-1,8 dihydroxy-3,6 naphthalene disulfonic acid, trisodium salt (SPADNS) were effectively adsorbed by Cu(II)-thiourea modified cotton fibers (Cu(II)/Tu-MC) complex. FTIR, SEM, XPS analysis, thermogravimetric analysis, and potentiometric titration were utilized for characterization. The impact of the fundamental adsorption parameters was systematically investigated. The results reveal that the adsorption of ECR and SPADNS acid dyes occurs via a metal-coordination mechanism. Furthermore, the adsorption process follows the 2nd order kinetic model and Langmuir model adsorption isotherm. The Cu(II)/Tu-MC shows high adsorption capacities of 0.27 and 0.22mmol/g for ECR and SPADNS, respectively. These findings indicate that the cationization of cellulose fibers with metal ions is a promising and efficient strategy toward enhancing the adsorption of acid dyes.

High Proton Conductivity of 3D Graphene Oxide Intercalated with Aromatic Sulfonic Acids.

The development of efficient proton conductors that are capable of high power density, sufficient mechanical strength, and reduced gas permeability is challenging. Herein, we report the development of a series of aromatic sulfonic acid/graphene oxide hybrid membranes incorporating benzene sulfonic acid (BS), naphthalene sulfonic acid (NS), naphthalene disulfonic acid (DS) or pyrene sulfonic acid (PS) using a facile freeze dried method. For out-of-plane proton conductivity, the 3DGO-BS and 3DGO-NS yielded proton conductivities of 4.4×10-2 S cm-1 and 3.1×10-2 S cm-1 , respectively; this represents a two-times higher value than that which occurs for three dimensional graphene oxide (3DGO). Additionally, the respective prepared films as membranes in a proton exchange membrane fuel cell (PEMFC) show maximum power density of 98.76 mW cm-2 for 3DGO-NS while it is 92.75 mW cm-2 for 3DGO-BS which are close to double that obtained for 3DGO (50 mW cm-2 ).

Structure determination of liquid molecules by encapsulation in an aromatic cavity with hydrogen bonding and enhanced C–H⋯π interactions

Guanidinium–naphthalenedisulfonic acid was used as a molecular catcher because (i) it contains a cavity and channel in the network; (ii) has both hydrogen bond donor and acceptor; and (iii) can form aromatic interactions with guest molecules.

Coupling regeneration strategy of lithium-ion electrode materials turned with naphthalenedisulfonic acid.

The resource exhaustion and environmental assessment driven by sustainable development make recycle of spent LIBs urgent to be achieved. However, the conventional recycling processes are quite complicated in terms of the tedious steps and secondary contamination. In this paper, hydrosoluble naphthalenedisulfonic acid is firstly proposed to selectively extract valuable metals (Co and Li) for the regeneration of battery materials. Lithium is selectively recovered as lithium enriched solution with a high yield of 99%, while 96.6% cobalt remains in a complex-precipitate benefited from the high acidity and coordination role of naphthalenedisulfonic acid. The leaching of Li fits well with the logarithmic rate law model with an activation energy of 32.42kJ/mol. Additionally, the regenerated lithium-ion battery active materials (Co3O4 anode and LiCoO2 cathode) prepared from the cobalt complex-precipitate and lithium-enriched solution exhibit excellent discharged-charged performances and rate capability. This feasible strategy assisted by multifunctional naphthalenedisulfonic acid may offer an alternative option for the simultaneous recovery of Li and Co and the rational resource utilization of spent lithium-ion batteries.

Hybrid Nafion Membranes of Ionic Hydrogen-Bonded Organic Framework Materials for Proton Conduction and PEMFC Applications.

As the high-power density and environmentally friendly energy resources, proton exchange membrane fuel cells (PEMFCs) have a promising future in portable power generation. Herein, the hybrid Nafion membranes of ionic hydrogen-bonded organic frameworks (iHOFs) for PEMFC applications are demonstrated. By adjusting the position of sulfonic groups on naphthalene disulfonic acid compounds, four iHOFs with different types of hydrogen bonds were synthesized successfully based on 1,1'-diamino-4,4'-bipyridylium and naphthalene disulfonic acid. The formation of hydrogen bond interactions between amino and sulfonate groups provides a rich hydrogen bond network, which makes such iHOFs have high conductivity, and the maximum value is 2.76 × 10-3 S·cm-1 at 100 °C and 98% RH. Besides, composite membrane materials were obtained by mixing Nafion and iHOFs, and the maximum proton conductivity values can achieve 1.13 × 10-2 S·cm-1 for 6%-iHOF-3/Nafion and 2.87 × 10-3 S·cm-1 for 6%-iHOF-4/Nafion membranes at 100 °C under 98% RH. Through the H2/O2 fuel cell performance test by using iHOF/Nafion as the solid electrolyte, the maximum power and current density values of hybrid membranes are 0.36 W·cm-2 and 1.10 A·cm-2 for 6%-iHOF-3/Nafion and 0.42 W·cm-2 and 1.20 A·cm-2 for 6%-iHOF-4/Nafion at 80 °C and 100% RH. This work provides a practicable approach for establishing high-performance proton exchange hybrid membranes by doping high proton-conducting iHOFs into the Nafion matrix.

Semi-Crystalline Polyaniline with an Enhanced Conductivity Synthesized with a Novel Binary Dopant Sulfonic Acid-Surfactant: Mechanical, Electrical and Shielding Performances of Nylon/PANI Conductive Fabrics at 9.45 GHz

Aniline was doped by a novel binary dopant agent, sulfonic acid-surfactant. Naphthalene disulfonic acid (NDSA) and an anionic surfactant (sodium dodecyl sulfate, SDS) were used to form the binary dopant agent; synthesis of the doped PANI was accomplished by using ammonium peroxydisulfate (APS) as the oxidant via a hybrid microemulsion polymerization at various temperatures (–10, 0, 20, and 40 °C). The synthesized polyaniline (PANI-NDSA-SDS) salts were characterized by Fourier transform infrared, UV-visible and Raman spectroscopy, X-ray diffraction, scanning electron microscopy (SEM), the electrical properties were determined using a four-point probe method, and the mechanical properties of the fabric samples were also studied. The PANI-NDSA-SDS salts showed a semi-crystalline structure with nanostructure morphology. Among the four polyaniline salts, the PANI-NDSA-SDS prepared at 20 °C showed higher values of conductivity and polymerization yield. In this study, this polyaniline salt was used as coating materials for preparation of conductive Nylon fabrics. As a result, the tensile strength increased by 15%, from 27.21 to 31.42 MPa. Higher electrical performance was obtained for the Nylon/polyaniline composites, 128–724 ohm/square; thus, for electromagnetic shielding applications, the conducting polyaniline coated Nylon fabrics can be used as a shield material for the control of electromagnetic interference at 9.45 GHz, the frequency of the instrument used for the measurements. The conducting fabrics showed an electromagnetic interference value between 20.09 and 34.44 dB.

Identification of LC-HRMS nontarget signals in groundwater after source related prioritization

Groundwater is a major drinking water resource but its quality with regard to organic micropollutants (MPs) is insufficiently assessed. Therefore, we aimed to investigate Swiss groundwater more comprehensively using liquid chromatography high-resolution tandem mass spectrometry (LC-HRMS/MS). First, samples from 60 sites were classified as having high or low urban or agricultural influence based on 498 target compounds associated with either urban or agricultural sources. Second, all LC-HRMS signals were related to their potential origin (urban, urban and agricultural, agricultural, or not classifiable) based on their occurrence and intensity in the classified samples. A considerable fraction of estimated concentrations associated with urban and/or agricultural sources could not be explained by the 139 detected targets. The most intense nontarget signals were automatically annotated with structure proposals using MetFrag and SIRIUS4/CSI:FingerID with a list of >988,000 compounds. Additionally, suspect screening was performed for 1162 compounds with predicted high groundwater mobility from primarily urban sources. Finally, 12 nontargets and 11 suspects were identified unequivocally (Level 1), while 17 further compounds were tentatively identified (Level 2a/3). amongst these were 13 pollutants thus far not reported in groundwater, such as: the industrial chemicals 2,5-dichlorobenzenesulfonic acid (19 detections, up to 100 ng L−1), phenylphosponic acid (10 detections, up to 50 ng L−1), triisopropanolamine borate (2 detections, up to 40 ng L−1), O-des[2-aminoethyl]-O-carboxymethyl dehydroamlodipine, a transformation product (TP) of the blood pressure regulator amlodipine (17 detections), and the TP SYN542490 of the herbicide metolachlor (Level 3, 33 detections, estimated concentrations up to 100–500 ng L−1). One monitoring site was far more contaminated than other sites based on estimated total concentrations of potential MPs, which was supported by the elucidation of site-specific nontarget signals such as the carcinogen chlorendic acid, and various naphthalenedisulfonic acids. Many compounds remained unknown, but overall, source related prioritisation proved an effective approach to support identification of compounds in groundwater.

Effect of a temperature threshold on the electrorheological performance of ionic liquid crystal polyanilines

A series of ionic liquid crystal polyanilines (ILCPs) electrorheological (ER) compounds were synthesized by use of polyaniline, naphthalene disulfonic acid and pyridinyl-containing mesogen. The chemical structure, thermal property, morphology, liquid-crystalline behavior, dielectric property and ER effect of the ILCPs-based ER fluids were characterized by use of various experimental techniques. The synthesized ILCPs displayed nematic liquid-crystalline phase, and the different mesogens played a determinant role in the liquid crystal behavior. The experimental results about dielectric property of the ILCPs suggested that both dielectric constant and dielectric loss increase with raising the temperature, showing a sudden change around glass-transition temperature. The ILCPs-based ER fluids contained an integrated character of liquid crystal, poly(ionic liquid) and polyaniline-base ER suspensions. These characteristics had strong dependence on operating temperature, and a temperature threshold was observed on the ER performance. The shear stress of the ER fluids increased abnormally near glass-transition temperature, which was due to the synergetic effect between the mesogenic orientation and the stretched polyaniline droplets induced by the electric field.

Kinetic Study of the Effect of the Micellar Concentration of Sodium Dodecyl Sulfate on the Spectroscopic, Morphological and Electrical Characteristics of a Polyaniline Prepared by a Hybrid Micro-Nanoemulsion Bi-Micellar Polymerization Technique

In the present work a study of the micro-nanoemulsion polymerization of aniline (ANI) was undertaken by employing two kinds of micelles as binary dopants, one type based on one of three sulfonic acids, dodecyl benzene sulfonic acid (DBSA), naphthalene-disulfonic acid (NDSA) or para-toluene sulfonic acid (TSA)), and the other based on an added surfactant (sodium dodecyl sulfate (SDS)). The effects of the important parameters, SDS concentration, sulfonic acid nature and temperature, were studied. The resulting polyaniline salts were characterized by attenuated total reflectance-Fourier transform infrared (ATR-FTIR), Raman and X-ray fluorescence (XRF) spectroscopy, scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and by a standard electrical resistance four-probe method. The SDS concentration had the predominant role in the doping level, thereby affecting the resultant conductivity. The present investigation revealed that the key parameters, SDS concentration, temperature and sulfur content, in the final product were influential in determining the PANI properties. The oxidation degree increased with a decrease in temperature of polymerization. It was found that the polymerization yield and electrical conductivity of the polyaniline salts PANI-NDSA-SDS and PANI-DBSA-SDS prepared with the critical micelle concentration (CMC) had the highest values and the polymer became thermally more stable. The highest electrical conductivity value obtained was 92.25 S/cm for PANI-NDSA-SDS prepared at 20 °C with the CMC of the SDS.

In situ chemical deposition of PPy/NDSA and PPy/DBSA layers on QCM electrodes: synthesis, structural, morphological and ammonia sensing performances study

Aiming to detect ammonia vapor, polypyrrole (PPy) thin layers were in situ coated on AT-cut 10 MHz quartz crystal microbalance QCM electrode by a facile chemical polymerization process using two organic acids as dopants, i.e. dodecylbenzene sulfonic acid (BDSA) and 1–5 naphthalene disulfonic acid (NDSA). Then after, polymers structural and morphological features were determined by FTIR, Raman spectroscopy and Scanning Electron Microscopy (SEM) techniques. Ammonia vapor sensing tests were related to QCM frequency changes recorded upon vapor adsorption and desorption on PPy films, it was found that frequency shifts varied linearly with both vapor concentration expressed in part per million (ppm) and polymer’s thin layer thickness given in nanometer (nm). This fact has been assumed to be mainly related to the electrostatic interactions established between ammonia vapor molecules and the polymer dopant agents. Tests have shown that films based PPy/NDSA exhibit high sensitivity around 3 ppm and detection limit of 4 ppm over films based PPy/DBSA. Interestingly, an excellent recovery time less than 3 min has been also recorded with PPy/NDSA thin layers. Moreover, when applying Fick’s second law, they have also shown a high diffusion constant.

Hybrids from the π−π Stacking of Graphene Oxide and Aromatic Sulfonic Compounds for Improved Proton Conductivity

Abstractπ‐π stacking between GO and benzene sulfonic acid (BS), naphthalene sulfonic acid (NS), pyrene sulfonic acid (PS), and naphthalene disulfonic acid (ND) results in the formation of respective GO‐BS, GO‐NS, GO‐PS and GO‐ND hybrid materials. The proton conductivities of these materials follow the trend as GO‐NS>GO‐BS>GO‐PS>GO>GO‐ND. GO‐NS, possessing the highest interlayer distance, exhibits the optimum proton conductivity. Evidently, GO‐sulfonic acid hybrids reveal excellent superionic conductivity.

Abstract 5744: The role of atypical protein kinase C in colorectal cancer cell growth and proliferation

Abstract Colorectal cancer (CRC) is the second most common cancer in the world and death from colorectal cancer accounts for 8% of all cancer deaths both in men and women in the United States. CRC is life threatening disease due to therapy resistant cancerous cells. The exact mechanisms of cell growth, survival, metastasis and inter & intracellular signaling pathways involved in colon cancer are still a major challenge for scientists. Hence, investigating the signaling pathways that lead to colon carcinogenesis may give insight into the therapeutic target. In this study, the role of atypical Protein kinase C (aPKC) on colon cancer was identified by using four inhibitors of that particular protein class: 1) ACPD (2-acetyl-1,3-cyclopentanedione and 2) DNDA (3,4-diamino-2,7 naphthalenedisulfonic acid) are non-specific inhibitors of aPKCs; 3) ζ-Stat (8-hydroxy-1, 3, 6-naphthalenetrisulfonic acid) is a specific inhibitor of PKC-ζ; and 4) ICA-I (4, 5-amino-4-carbamoylimidazol-1-yl-2, 3-dihydroxycyclopentyl) methyl dihydrogen phosphate) is a specific inhibitor of PKC-ι. The cell lines tested were HT-29 colon cancer and CCD18CO normal colon epithelial. Although PKC-ι is an oncogene in many cancers, we found that the PKC-ζ was responsible for the abnormal growth and proliferation in HT-29 colon cancer cells. Additionally, the inhibition of aPKCs did not bring any significant toxicity on CCD18CO normal colon cell line. These results suggest the potentiality of utilizing aPKC-ζ inhibitors to block colon cancer cell growth and proliferation. Citation Format: S M Anisul Islam, Mildred Acevedo Duncan. The role of atypical protein kinase C in colorectal cancer cell growth and proliferation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5744. doi:10.1158/1538-7445.AM2017-5744

Simple and sensitive determination of trace nitrite in water by zero-crossing first-derivative synchronous fluorescence spectrometry using 6-amino-1,3- naphthalenedisulfonic acid as a new fluorescent probe.

A new fluorescent probe, 6-amino-1,3-naphthalenedisulfonic acid (ANDSA), has been developed for the determination of trace nitrite in different waters. This probe is based on the selective reaction of nitrite with ANDSA in hydrochloric acid solution to form the corresponding diazonium acid in sodium hydroxide solution at room temperature. The diazonium acid produced has high fluorescence intensity at 488 nm (excitation at 367 nm), whereas ANDSA has high fluorescence intensity at 465 nm (excitation at 354 nm). The synchronous fluorescence (Δλ = 121 nm) spectrum and the first-derivative synchronous fluorescence spectrum of diazonium acid greatly overlapped with those of ANDSA. The zero-crossing method was used to measure the first-derivative value (dF/dλ) of the first-derivative spectra, in which physical separation of excess ANDSA was unnecessary. The zero-crossing point was located at 351.2 nm for ANDSA, at which dF/dλ of diazonium acid was proportional to the nitrite concentration. Therefore, dF/dλ at 351.2 nm was selected as the analytical signal. Under the optimized experimental conditions, the signal intensity was linear over a nitrite concentration range of 0.006-0.075 mg L-1, with a correlation coefficient better than 0.9994. The limit of detection was 2.1 μg L-1 for the determination of nitrite by the proposed method. The relative standard deviation of the method for the determination of nitrite in real water samples was below 2.45%, and the corresponding recoveries were between 95.7% and 104.1%. The validity of the proposed method was further confirmed by comparison with the reference method with use of the t test. Graphical abstract ANDSA reacts with nitrite to form diazonium acid with higher fluorescence intensity. For ANDSA, dF/dλ was zero at 351.2 nm, whereas dF/dλ of diazonium acid at 351.2 nm was close to the maximum value.