THE COLOUR REACTION OF CADMIUM WITH 1-(2-BENZOTIIIAZOLYL)-3-(4-PHENYLAZOPHENYL)-TRIAZENE AND ITS APPLICATION

Abstract: A new triazene reagent 1-(2-benzothiazolyl)-3-(4-phenylazoghecyl )-triazece (BTPAPT) has been synthesized.The clour reaction of STPAPT with Cd (Ⅱ) has been studied. At pH=9～11,in the presence of Triton X-100,the reagent with Cd (Ⅱ) forms a complex with high sensitivity, the molar ratio of Cd (Ⅱ) to BTPAPT is 1: 2. The molar absarptlvity is 1. 4 × 10-5 L. mol-1. cm-1. Beer's law is obeyed for Cd (Ⅱ) in the range of 0-14 μg/25ml.

Synthesis of 1-(4-Antipyrinyl)-3-(3-Chlorophenyl)-Triazene and Its Colour Reaction with Mercury

A uew diazoamino reagent 1-(4-antipyrinyl)-3-(3-Chlorophenyl)-triarene(APCPT)was synthesized. The colour reaction of APCPT with Hg(II) was studied. At pH=10,5~12.2, in the presence of Tween-80,APCPT reacts with Hg(II) to form a red complex witk higb sensitivity.The molar ratio of Hg(II) to APCPT is 1:2. The molar absorptivity is 1.87 × 105L . mor． cm-1.Beer's law is obeyed for Hg in the range of0-16μg/25ml

Molecular and Crystal Structure of 1-(4-Chlorophenyl)-3-(2-nitrophenyl)-1-triazene

The title compound, 1 (4 chlorophenyl) 3 (2 nitrophenyl) 1 triazene (C 12 \|H 9ClN 4O 2, M r =276.68) crystallized in the orthorhombic system,space group Pbca (#15), with a=7.040(1), b=13.520(2), c=26.253(3), V=2498.8(6) 3, D c =1.471g/cm 3, Z=8, μ (Mo Kα )=0.309mm -1 , F (000)=1136. The final R and wR are 0.0345 and 0\^0608 for 2428 observed reflections ( I>2σ(I) ), respectively. The title molecule has trans geometry about the central triazenyl linkage. The dihedral angle between the two phenyl rings is 5.5(2)° and the twist angle for the nitro group is 6.9(2)°. The whole molecule is almost coplanar, which results mainly from the intramolecular hydrogen bonds and the resonance effect in the middle of the skeleton. In the crystal structure, the inversion centre related molecules are packed anti parallely into mixed stacks through π…π interactions along [100] direction, and the interstack forces are mainly the hydrogen bonds and van der Waals interactions.

1-(4-ANTIPYRINYL)-3-(2, 4-DINITROPHENYL)-TRIAZENE AND ITS COLOUR REACTION WITH CADMIUM

A new reagent,1(4 antipyriny1) 3(2,4-dinitropheny1)triazene(APDNBT), was synthesized in this lab and its analytical properties and its colour reaction with cadmium were studied.

Spectroscopic Electrochemical Properties and DFT Calculation of 1-Aryltriazenes

Electrochromic materials are of great interest for their potential in eyewear protection and data storage devices, as they change colors in response to electrochemical switching. While many of the systems currently used are based on inorganic materials, organic materials such as triazenes have emerged as viable alternatives due to their unique properties, including optical properties. Triazenes are a class of organic compounds with three consecutive nitrogen atoms in an acyclic arrangement, and they have been used for a variety of applications in medicinal and synthetic chemistry. However, the effects of solvents on the UV-visible absorption spectrum of triazenes have not been fully investigated. The neutral molecules of 3,3-diisopropyl-1-phenyltriazene and 1-(4-chlorophenyl)-3-cyclopentyltriazene in acetonitrile, the UV-visible spectra corresponded respectively to HOMO → LUMO transitions with a large maximum absorption at 299.74 nm (4.1364 eV) and 299.57 nm (4.1387 eV) and the most intense oscillator strength (f = 0.6988) and (f = 0.7372). These results suggest that the electronic transitions of the compounds are highly influenced by the nature of the substituents on the triazene unit, as well as the solvent used in the experiment. The redox couple 0.92 and -0.44 V/Ag/AgCl is attributed to the phenyl group. Compound III showed an oxidation and reduction peak respectively -0.27 and -0.8 V/Ag/AgCl attributed to the phenyl molecule. The study concluded that all three compounds were electroactive and exhibited reversible characteristics with oxidizing/reducing couples. This study aims to contribute to research on the optical properties of triazenes compounds and the application of quantum chemical calculation methods for understanding their molecular structures. By investigating the solute-solvent interactions occurring in the solvation shell of the solutes, we aim to gain insights into the effects of solvents on the UV-visible absorption spectrum of triazenes. Our findings may have implications for the development of functionalized triazenes as potential electrochromic materials.

The Colour Reaction of Mercury with 1-(6-Ethoxyl-2-benzothiazolyl)-3-(4-Nitrophenyl)-Triazene and its Application

A new triazene reagent 1-(6-ethoxyl-2-benzothiazolyl)-3-(4-nitrophenyl)-triazene (EtOBThTPT) has been synthesized. The colour reaction of EtOBTNPT with Hg(II) has been studied. At pH = 10.1-10.7, in the presence of Triton X-100, the reagent with Hg(II) forms an orange-yellow complex with high sensitivity. The molar absorptivity is 2.38 X 10(5) L.mol(-1).cm(-1). Beer's law is obeyed for Hg(II) in the range of 0-7 mu g/25 ml.

Synthesis of A New Reagent 1-(6-Nitro-2-Benzothiazolyl)-3-(4-Nitrophenyl)-Triazene and Study on Its Color Reaction with Cadmium

This paper introduces the synthesis of a new color reagent 1-(6-nitro-2-benzothiazolyl)3-(4-nitrophenyl)-triazene (NBTNPT) and the color reaction of NBTNPT with Cd (II) has been studied. In the presence of Triton X-100, the reagent with Cd (II) forms an orange-yellow complex (1:1) at pH=11.5-12.3, the molar absorptivity is 2.81x10(5)L . mol(-1)m(-1) by dual-wavelength spectrophotometry, Beers law is obeyed in the range of 0-280 mu g/L for Cd (II).

Synthesis of 1-(5-nitro-3-benzopseudothiazolyl)-3-(4-phenylazophenyl)-triazene and Its Color Reaction with Cobalt

A new chromogenic reagent, 1 -（5 - nitro- 3 - benzopsendothiazde）- 3 -（4 - phenylazophenyl） - triazene （NBPTPAPT） has been synthesized and used as a sensitive reagent for the spectrophotometric determination of cobalt. In the presence of Tween - 80, the reagent with Co （ Ⅱ ） forms a yellow complex （1 ： 2） in the buffer solution of Na2B4O7 - NaOH at pH 10.54. The apparent molar absorptivity is 1.220× 10^5 L· mol^- 1· cm^- 1 with the linear range of 0 - 240μg/ L for Co （Ⅱ） by dual-wavelength spectrophotometry. Trace cobalt in vitamin B12 and tea samples has been determined with satisfactory results.

Determination of Mecruy at Trace Level in Natural Water Samples by Hydride Generation Atomic Absorption Spectrophotometry after Cloud Point Extraction Preconcentration

A method for the determination of trace mercury in water samples by hydride generation atomic absorption spectrophotometry after cloud point extraction was proposed in the present work. The effects of pH, concentration of surfactant, and equilibration time on cloud point extraction were discussed. The enhancement factor of 20 and the detection limit of 0.039 μg/L were obtained for mercury with relative standard deviation of 4.8% （n = 11）.

Synthesis and characterization of functionalized 1,3-bis(2-alkyltetrazol-5-yl)triazenes

A series of 1,3-bis（2-alkyltetrazol-5-yl）triazenes have been synthesized in high yields by treatment of sodium nitrite and hydrochloric acid with substituted-5-aminotetrazoles. All compounds were fully characterized using IR spectroscopy,~1H NMR and^（13） C NMR spectroscopy and high resolution mass spectrometer（HRMS）. Most of these triazenes exhibit good detonation performance comparable with TNT and low melting points ranging from 81°C to 106°C, which are suitable for melt-cast explosives.Among these compounds, 1,3-bis（2-azidoethyltetrazol-5-yl）triazene（2g） displays a low melting point（106°C）, moderate onset decomposition temperature（183°C） and good detonation performance（D：7087 m/s; P： 17.6 GPa）.

Determination of Total Flavones Content in Ceratocarpus arenarius L. by Spectrophotometry

[Objective] The aim was to establish the method for determining total flavoens content in Ceratocarpus arenarius L.[Method ] Flavonoids were extracted from C. arenarius by heating refluxing, and determined with rutin as the standard.[Result] In the range of 0.019-0.102 mg/ml, linear relationship was good （r=0.999 1）. This method had higher precision and accuracy with RSD of 0.226% and recoveries of 99.36%. The total flavones content from C. arenarius was 10.12 mg/g. [Conclusion] The method is simple and reliable, which could be used to control the quality of C. arenariu.

Preparation of pyrido[1,2-c][1,2,4]triazole-based π-conjugated triazene as a Fe3+ ion fluorescent sensor

A highly efficient coupling reaction of N-heterocyclic carbene precursors with sulfonyl azides has been developed, affording a variety of pyrido[1,2-c][1,2,4]triazole-based π-conjugated triazenes. The present reaction proceeds under very mild conditions with good functional group tolerance. The resulting triazenes exhibit selective and sensitive fluorescent response toward Fe3+ion.

New Approach to Detecting Phenoxyl Free Radicals Generated in Enzyme Reaction by Stopped-flow Spectrophotometry

A highly sensitive stopped-flow spectrophotometry kinetic method was proposed for quantification phenoxyl radicals based on their accelerating effect on the oxidation of nicotinamide adenine dinucleotide （NADH）. Phenoxyl radicals generated from as low as 1×10^-8 mol/L 2,4-DCP can be readily detected with the proposed method and the detecting limit was 2.5×10^-9 mol/L.

Quantitative Determination of Benoxinate Hydrochloride by Three Wavelength Spectrophotometry

hree wavelength spectrophotometry was used to determine the content ofbenoxinate hydrochloride.Using this method could effectively eliminate the devia-tion of background absorption caused by the change of concentration and the errorof quantitative anaiysis caused by asymmetric peaks, and at the same time the lean-ing degree of base line was corrected.This method was simple, the recovery was98. 62% 101. 86% and the coefficient of variation was 0. 551%.

Rapid measurement of indocyanine green retention by pulse spectrophotometry: a validation study in 70 patients with Child-Pugh A cirrhosis before hepatectomy for hepatocellular carcinoma

BACKGROUND: The indocyanine green (ICG) retention test is the most popular liver function test for selecting patients for major hepatectomy. Traditionally, it is done using spectrophotometry with serial blood sampling. The newly- developed pulse spectrophotometry is a faster alternative, but its accuracy on Child-Pugh A cirrhotic patients undergoing hepatectomy for hepatocellular carcinoma has not been well documented. This study aimed to assess the accuracy of the LiMON , one of the pulse spectrophotometry systems, in measuring preoperative ICG retention in these patients and to devise an easy formula for conversion of the results so that they can be compared with classical literature records where ICG retention was measured by the traditional method. METHODS: We measured the liver function of 70 Child-Pugh A cirrhotic patients before hepatectomy for hepatocellular carcinoma from September 2008 to January 2009. ICG retention at 15 minutes measured by traditional spectrophotometry (ICGR15) was compared with ICG retention at 15 minutes measured by the LiMON (ICGR15(L)). RESULTS: The median ICGR15 was 14.7% (5.6%-32%) and the median ICGR15(L) was 10.4% (1.2%-28%). The mean difference between them was -4.3606. There was a strong correlation between ICGR15 and ICGR15(L) (correlation coefficient, 0.844; 95% confidence interval, 0.762-0.899). The following formula was devised: ICGR15=1.16×ICGR15(L)+2.73.CONCLUSIONS: The LiMON provides a fast and repeatable way to measure ICG retention at 15 minutes, but with constant underestimation of the real value. Therefore, when comparing results obtained by traditional spectrophotometry and the LiMON, adjustment of results from the latter is necessary, and this can be done with a simple mathematical calculation using the above formula.

Serum paraquat concentration detected by spectrophotometry in patients with paraquat poisoning

BACKGROUND：Paraquat （PQ） is a world-wide used herbicide and also a type of common poison for suicide and accidental poisoning. Numerous studies have proved that the concentration of serum PQ plays an important role in prognosis. Spectrophotometry, including common spectrophotometry and second-derivative spectrophotometry, is commonly used for PQ detection in primary hospitals. So far, lack of systematic research on the reliability of the method and the correlation between clinical features of patients with PQ poisoning and the test results has restricted the clinical use of spectrophotometry. This study aimed to evaluate the reliability and value of spectrophotometry in detecting the concentration of serum PQ. METHODS：The wavelengths for detecting the concentration of serum PQ by common and second-derivative spectrophotometry were determined. Second-derivative spectrophotometry was applied to detect the concentration of serum PQ. The linear range and precision for detection of PQ concentration by this method were confirmed. The concentration of serum PQ shown by second- derivative spectrophotometry and HPLC were compared in 8 patients with PQ poisoning. Altogether 21 patients with acute poisoning 4 hours after PQ ingestion treated in the period of October 2008 to September 2010 were retrospectively reviewed. The patients were divided into higher and lower than 1.8 μg/mL groups based on their concentrations of serum PQ measured by second-derivative spectrophotometry on admission. The severity of clinical manifestations between the two groups were analyzed with Student＇s t test or Fisher＇s exact test. RESULTS：The absorption peak of 257 nm could not be found when common spectrophotometry was used to detect the PQ concentration in serum. The calibration curve in the 0.4-8.0 μg/mL range for PQ concentration shown by second-derivative spectrophotometry obeyed Beer＇s law with r=0.996. The average recovery rates of PQ were within a range of 95.0% to 99.5%, relative standard deviation （RSD） was within 1.35% to 5.41% （n=6）, and the lower detection limit was 0.05 μg/mL. The PQ concentrations in serum of 8 patients with PQ poisoning shown by second-derivative spectrophotometry were consistent with the quantitative determinations by HPLC （r=0.995, P〈0.0001）. The survival rate was 22.2% in patients whose PQ concentration in serum was more than 1.8 μg/mL, and the incidences of acidosis, oliguria and pneumomediastinum in these patients were 55.6%, 55.6% and 77.8%, respectively. These clinical manifestations were different significantly from those of the patients whose PQ concentration in serum was less than 1.8 pg/mL （P〈0.05）. CONCLUSIONS： For common spectrophotometry, the wavelength at 257 nm was not suitable for detecting serum PQ as no absorbance was shown. Second-derivative spectrophotometry was reliable for detecting serum paraquat concentration. Serum PQ concentration detected by second- derivative spectrophotometry could be used to predict the severity of clinical manifestations of patients with PQ poisoning, and PQ content higher than 1.8 tJg/mL 4 hours after ingestion could be an important predictive factor for poor prognosis.

Quantitative analysis of cefixime via complexation with palladium(Ⅱ) in pharmaceutical formulations by spectrophotometry

An optimized and validated spectrophotometric method has been developed for the determination of cefixime in pharmaceutical formulations. The method is based on the complexa- tion reaction between cefixime and palladium ion in the presence of acidic buffer solution （pH 3） in ethanol-distilled water medium at room temperature. The complex absorbed maximally at 352 nm. Beer＇s law is obeyed in the working concentration range of 2.5-35 μg/mL with apparent molar absorptivity of 1.015×104 L/mol cm and Sandell＇s sensitivity of 0.001 μg/cm2/0.001 absorbance unit. The limits of detection and quantitation for the proposed method are 0.175 and 0.583μg/mL, respectively. The effect of common excipients used as additives has been studied in the determination of cefixime. The proposed method has been successfully applied for the determina- tion of cefixime in pharmaceutical formulations. The results obtained by the proposed method were statistically compared with the reference method using t and F values and found no significant difference between the two methods.

Application of derivative ratio spectrophotometry for determination of β-carotene and astaxanthin from Phaffia rhodozyma extract

A derivative ratio spectrophotometric method was used for the simultaneous determination of β-carotene and astaxanthin produced from Phaffia rhodozyma. Absorbencies of a series of the standard carotenoids in the range of 441 nm to 490 nm demonstrated that their absorptive spectra accorded with Beer’s law and that the additivity when the concentrations of β-carotene and astaxanthin and their mixture were within the range of 0 to 5 μg/ml, 0 to 6 μg/ml, and 0 to 6 μg/ml, respectively. When the wavelength interval (?λ) at 2 nm was selected to calculate the first derivative ratio spectra values, the first derivative amplitudes at 461 nm and 466 nm were suitable for quantitatively determining β-carotene and astaxanthin, respectively. Effect of divisor on derivative ratio spectra could be neglected; any concentration used as divisor in range of 1.0 to 4.0 μg/ml is ideal for calculating the derivative ratio spectra values of the two carotenoids. Calibration graphs were established for β-carotene within 0?6.0 μg/ml and for astaxanthin within 0?5.0 μg/ml with their corresponding regressive equations in: y=?0.0082x?0.0002 and y=0.0146x?0.0006, respectively. R-square values in excess of 0.999 indicated the good linearity of the calibration graphs. Sample recovery rates were found satisfactory (>99%) with relative standard deviations (RSD) of less than 5%. This method was suc- cessfully applied to simultaneous determination of β-carotene and astaxanthin in the laboratory-prepared mixtures and the extract from the Phaffia rhodozyma culture.

Catalytic Spectrophotometry for Vanadium Determination Based on Oxidation of Arsenazo Ⅲ by Bichromate

A catalytic spectrophotometry for the determination of trace amount of vanadium was developed based on its catalytic effect on the oxidation of arsenazo by potassium bichromate in weak acidic medium. The optimized conditions for determinations are: cK2Cr2O7=3.010-5 molL-1, carsenazo =3.010-5 molL-1, pH=4.0, t=90. The calibration graph is linear for 0.020.2 gml-1, and the detection limit is 0.02 gml-1 V. The apparent active energy of this catalytic reaction is 21.72 kJmol-1. Most foreign ions do not interfere with the determination of vadadium, except for Fe() and Co(), and their interferences could be eliminated by ion exchange. The present method has been used to make the determination of vanadium in human hair, tea, potato and wastewater, and the results were satisfactory.

Analysis of Peanut Oil Adulterated with Other Edible Oils by Spectrophotometry

Since peanut oil（PO） is more expensive than other seed oils, some PO is adulterated with other cheap seed oils, such as soybean oil, palm olein, cottonseed oil, corn oil and rapeseed oil. The conventional method for deter mining whether PO was adulterated is to detect the freezing point of oils. The proposed method for the determination of adulterants in PO was based on monitoring the change of absorbance when the sample was refrigerated. A special spectrophotometer was developed. A total of 10 kinds of POs from different suppliers were chosen and adulterated with other seed oils at the volume fraction levels ranging from 5% to 30%. A total of 150 samples were analyzed by the proposed method and the results were satisfactory.