Poly(phenylene oxide)(PPO)exhibits excellent dielectric properties,making it an ideal substrate for high-frequency,high-speed copper-clad laminates.The phenolic hydroxyl group at the end of PPO plays a key role in its...Poly(phenylene oxide)(PPO)exhibits excellent dielectric properties,making it an ideal substrate for high-frequency,high-speed copper-clad laminates.The phenolic hydroxyl group at the end of PPO plays a key role in its reactivity.Accurately quantifying the phenolic hydroxyl content in PPO is essential but challenging.In this study,we proposed a method for measuring the phenolic hydroxyl content of PPO using differential UV absorption spectroscopy.In alkaline solutions,the phenolic hydroxyl in PPO completely ionizes to form phenoxide ions,leading to a significant increase in UV absorbance at approximately 250 and 300 nm.Notably,the differential UV absorbance at approximately 300 nm was directly proportional to the phenolic hydroxyl concentration.Using 2,6-dimethylphenol as a standard,a calibration curve was established to relate the phenolic hydroxyl concentration to differential UV absorbance at approximately 300 nm,providing a precise and straightforward method for phenolic hydroxyl quantification in PPO with distinct advantages over conventional techniques.展开更多
[Objectives]Based on spectrophotometry,a method for determining the total flavonoid content in milk powder was established by optimizing sample pretreatment conditions,and method validation was performed.[Methods]Tota...[Objectives]Based on spectrophotometry,a method for determining the total flavonoid content in milk powder was established by optimizing sample pretreatment conditions,and method validation was performed.[Methods]Total flavonoids in milk powder were extracted with ethanol using 45℃ water bath ultrasonication for 60 min.Flavonoids contain a benzopyran ring structure and react with aluminum nitrate in a potassium acetate environment to form a yellow complex.The absorbance of this complex was measured at 420 nm for quantitative determination.[Results]The method exhibited a good linear relationship within the range of 0.2-1.0 mg.The limit of detection(LOD)was 0.05 g/100 g,and the limit of quantification(LOQ)was 0.3 g/100 g.When the spiked amount of total flavonoids was in the range of 0.3% to 1.0%,the spike recovery rates were 99.3% to 103.4%,and the relative standard deviations(RSD s)were less than 3.0%.[Conclusions]This method offers advantages such as rapidness,accuracy,good stability,and high sensitivity,and can be used for the detection of total flavonoid content in milk powder.展开更多
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...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.展开更多
[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 ...[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.展开更多
Two simple, rapid, accurate, precise, reliable and economical spectrophotometric methods have been proposed for the determination of galanthamine hydrobromide (GH) in bulk and pharmaceutical formulation. First method ...Two simple, rapid, accurate, precise, reliable and economical spectrophotometric methods have been proposed for the determination of galanthamine hydrobromide (GH) in bulk and pharmaceutical formulation. First method is zero order UV spectrophotometry and second is 1st derivative zero crossing spectrophotometry. The developed methods have shown best results in terms of linearity, accuracy, precision, LOD and LOQ for bulk drugs and marketed formulations. Absorbance was measured at 287 nm for zero order and 277.4 nm for first derivative. It obeyed Lambert-Beer’s law in the range of 30-80 μg mL-1. Both methods have good linearity (r2 = 0.9997) and accuracy found to be 100.5% and 101.2% for both methods respectively.展开更多
The combined derivative spectrophotometry developed in this paper is a new method, which can be used to determine multicomporent mixture simultaneously and may improve the sensitivity and accuracy of the measurement r...The combined derivative spectrophotometry developed in this paper is a new method, which can be used to determine multicomporent mixture simultaneously and may improve the sensitivity and accuracy of the measurement remarkably. Two practical tests were carried out to verify the correctness of the theory, and the results are satisfactory.展开更多
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...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.展开更多
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 concentratio...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%.展开更多
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 rang...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.展开更多
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 palladi...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.展开更多
DNA analysis is the core of biotechnology applied in petroleum resources and engineering. Traditionally accurate determination of DNA purity and concentration by spectrometer is the first and critical step for downstr...DNA analysis is the core of biotechnology applied in petroleum resources and engineering. Traditionally accurate determination of DNA purity and concentration by spectrometer is the first and critical step for downstream molecular biology research. In this study, three different spectrophotometry methods, BPM, NDTT and NPMTTZ were compared for their performance in determining DNA concentration and purity in 32 oil samples, and molecule methods like quantitative real-time PCR (qPCR) and high-throughput sequence were also performed to help assess the accuracy of the three methods in determining DNA concentration and purity. For ordinary heavy oil (OHO), extra heavy oil (EHO) and super heavy oil (SHO), the characteristics of high viscosity (η), density (ρ) and resin plus asphaltene content will affect the DNA extraction and UV determination. The DNA concentration was decreased as density increased: OHO (11.46 ± 18.34 ng/μL), EHO (6.68 ± 9.67 ng/μL) and SHO (6.20 ± 7.83 ng/μL), and the DNA purity was on the reverse: OHO (1.31 ± 0.27), EHO (1.54 ± 0.20), and SHO (1.83 ± 0.32). The results suggest that spectrophotometry such as BPM and NPMTTZ are qualitatively favorite methods as the quick non-consumable methods in determining DNA concentration and purity of medium oil and heavy oil.展开更多
A kind of sensitive, rapid, and simple spectrophotometry based on a Ytterbium(Yb3+) functionalized gold nanoparticle(Au NPs-Yb) was developed for detection of organophosphorus pesticides(OPs). Prepared AuNPs possess o...A kind of sensitive, rapid, and simple spectrophotometry based on a Ytterbium(Yb3+) functionalized gold nanoparticle(Au NPs-Yb) was developed for detection of organophosphorus pesticides(OPs). Prepared AuNPs possess oxygen-containing functional groups and strong complexation reaction with Yb3+. While oxygen-containing thiophosphate in the OPs molecule can combine with Yb3+as a cross-linking molecule to produce insoluble yetterbium phosphate, resulting in the aggregation of AuNPs and great decrease in ultraviolet absorbance strength at 520 nm by ultraviolet visible(UV-vis) spectrophotometer. Under the optimized conditions, a linear relationship between the absorbance of AuNPs and OPs concentration ranged from 0.05 μg/L to 6.0 μg/L with limit of detection for 0.03 μg/L(S/N = 3), which is far lower than the maximum residue limit(0.01 ppm) in the European Union pesticides database. Therefore, this assay has potential application in the determination of OPs in the field of environmental and food monitoring.展开更多
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, concentratio...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）.展开更多
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 co...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.展开更多
A new dual-wavelength dual-indicator catalytic kinetic spectrophotometric method for the determination of trace Ru(III)was studied.This method was based on Ru(III)-catalyzing oxidation of Arsenazo I and indigo carmine...A new dual-wavelength dual-indicator catalytic kinetic spectrophotometric method for the determination of trace Ru(III)was studied.This method was based on Ru(III)-catalyzing oxidation of Arsenazo I and indigo carmine by potassium bromate in sulfuric acid.The absorbances of the catalytic and noncatalytic systems were measured at 510 and610 nm,respectively.Under the optimum conditions,the linear range of determination is 0–0.12 lgáml-1and the detection limit is 1.21 9 10-4lgáml-1.The method was applied for the determination of trace Ru(III)in ore samples with satisfactory results.展开更多
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 mi...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.展开更多
CeO_(2)-based catalysts are widely investigated for selective catalytic reduction(SCR)of NO with NH3.Interaction of NO/O_(2) with CeO_(2) generally produces two surface species,i.e.,nitrates and nitrites.However,the e...CeO_(2)-based catalysts are widely investigated for selective catalytic reduction(SCR)of NO with NH3.Interaction of NO/O_(2) with CeO_(2) generally produces two surface species,i.e.,nitrates and nitrites.However,the explicit quantification of these two species is still unresolved.Herein,we reported that spectrophotometry characterization was effective in determining surface adsorbed NOx species on CeO_(2) by measuring the corresponding ions(NO_(2)-and NO_(3)^(-))dissolved in aqueous solution.Experimental results show that both nitrate(-NO_(3))and nitrite(-NO_(2))species can be quantitatively evaluated and the accuracy is verified by calibrating with NOx-TPD result.Exclusive transfer of adsorbed NOx from catalyst surface to aqueous solution is confirmed and the dissolution process can be accelerated by ultrasonic treatment.Moreover,useful information related to evolution of surface NOx species under various conditions(O_(2) treatment,different adsorption temperature and duration)and over different catalysts(Fe_(2)O_(3),MnO_(2) and MnOx—CeO_(2))are provided.The result of present study demonstrates the potential of spectrophotometry for quantitative discrimination of surface NOx species on CeO_(2) and other oxide-based materials,which is conducive to mechanism analysis of SCR reaction.展开更多
While engineered nanoparticles are widely used and maybe eventually released into the environment,natural nanoparticles are also commonly found in the Earth system.Nanoparticles may critically affect the geochemical m...While engineered nanoparticles are widely used and maybe eventually released into the environment,natural nanoparticles are also commonly found in the Earth system.Nanoparticles may critically affect the geochemical migration of associated elements and pose potential threats to the ecological environment.It is necessary to establish an accurate and reliable method for measuring the concentration of nanoparticles.AAS is one of the most commonly used methods for the concentration determination of nanoparticles.However,till now,there has been no systematic report on how experimental variables affect AAS measurements.In this study,we used gold nanoparticles(AuNPs) as an example and studied the influences of a list of factors on the concentration determination of AuNPs by AAS,including digestion method,ionization interference,acidic medium,background correction method,and organic matter.We demonstrate that all these factors may have varying degrees of influence on the measured gold concentrations.When the gold colloid is digested at room temperature for more than 8 h or at 60℃ for more than 2 h,and the system contains a low concentration of organic matter,AAS can accurately measure the AuNP concentration at ppm-level.The deuterium lamp background deduction method is not recommended to use for samples with lower gold concentrations.展开更多
A rapid, reliable and accurate method for the determination of hexavalent chromium in Portland cement is developed. The proposed method includes direct spectrophotometric determination of Cr (VI) in Portland cement wi...A rapid, reliable and accurate method for the determination of hexavalent chromium in Portland cement is developed. The proposed method includes direct spectrophotometric determination of Cr (VI) in Portland cement with 1, 2, 5, 8 Tetrahydroxyanthraquinone, (Quinalizarin, QINZ) at pH 1.5. The European Directive (2003/53/EC) limits the use of cements so that it contains no more than 2 mg.Kg-1 of water-soluble Cr (VI). The absorbance at 565 nm due to Cr (VI)-QINZ complex is recommended for the determination of water-soluble Cr (VI) in Portland cement. The quantification of Cr (VI) released from cement when mixed with water is performed according to TRGS 613 (Technical Rules of Hazardous Substances). The validity of the method is thoroughly examined and the proposed method gives satisfactory results. A derivative spectrophotometric method has been developed for the determination of total Cr (VI) in Portland cement in the presence of Fe (III) and Ti (IV). The hexavalent chromium complex formed at pH 1.5 allows precise and accurate determination of chromium (VI) over the concentration range 0.05 to 3.0 mg.L-1of chromium (VI). The validity of the method was examined by analyzing several Standard Reference Material (SRM) Portland cement samples. The MDL (at 95% confidence level) was found to be 25 ng/mL for chromium (VI) in National Institute of Standards and Technology (NIST) cement samples using the proposed method.展开更多
Ridge regression spectrophotometry(LHG)is used for thesimultaneous determination of five components(acetaminophen,p-aminophenol, caffeine, chlorphenamine maleate and guaifenesin)incough syr- up. The computer program o...Ridge regression spectrophotometry(LHG)is used for thesimultaneous determination of five components(acetaminophen,p-aminophenol, caffeine, chlorphenamine maleate and guaifenesin)incough syr- up. The computer program of LHG is based on VB language.The difficulties in overlapping of absorption spectrums of fivecompounds are overcome by this procedure. The experimental resultsshow that the recovery of each component is in the range from97.9/100 to 103.3/100 and each component obtains satisfactory resultswithout any pre-separation.展开更多
基金the“Pioneer”and“Leading Goose”R&D Program of Zhejiang(No.2023C01072)the Institute of Zhejiang University-Quzhou for their financial support。
文摘Poly(phenylene oxide)(PPO)exhibits excellent dielectric properties,making it an ideal substrate for high-frequency,high-speed copper-clad laminates.The phenolic hydroxyl group at the end of PPO plays a key role in its reactivity.Accurately quantifying the phenolic hydroxyl content in PPO is essential but challenging.In this study,we proposed a method for measuring the phenolic hydroxyl content of PPO using differential UV absorption spectroscopy.In alkaline solutions,the phenolic hydroxyl in PPO completely ionizes to form phenoxide ions,leading to a significant increase in UV absorbance at approximately 250 and 300 nm.Notably,the differential UV absorbance at approximately 300 nm was directly proportional to the phenolic hydroxyl concentration.Using 2,6-dimethylphenol as a standard,a calibration curve was established to relate the phenolic hydroxyl concentration to differential UV absorbance at approximately 300 nm,providing a precise and straightforward method for phenolic hydroxyl quantification in PPO with distinct advantages over conventional techniques.
基金Supported by Key Research and Development and Achievement Transformation Plan Project of Inner Mongolia Autonomous Region(2023YFHH0093).
文摘[Objectives]Based on spectrophotometry,a method for determining the total flavonoid content in milk powder was established by optimizing sample pretreatment conditions,and method validation was performed.[Methods]Total flavonoids in milk powder were extracted with ethanol using 45℃ water bath ultrasonication for 60 min.Flavonoids contain a benzopyran ring structure and react with aluminum nitrate in a potassium acetate environment to form a yellow complex.The absorbance of this complex was measured at 420 nm for quantitative determination.[Results]The method exhibited a good linear relationship within the range of 0.2-1.0 mg.The limit of detection(LOD)was 0.05 g/100 g,and the limit of quantification(LOQ)was 0.3 g/100 g.When the spiked amount of total flavonoids was in the range of 0.3% to 1.0%,the spike recovery rates were 99.3% to 103.4%,and the relative standard deviations(RSD s)were less than 3.0%.[Conclusions]This method offers advantages such as rapidness,accuracy,good stability,and high sensitivity,and can be used for the detection of total flavonoid content in milk powder.
基金This study was supported by a grant from the National Natural Science Foundation of China（No.30871202）.
文摘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.
基金Supported by International Science and Technology Cooperation Programme of Xinjiang Crops(2011BC003)~~
文摘[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.
文摘Two simple, rapid, accurate, precise, reliable and economical spectrophotometric methods have been proposed for the determination of galanthamine hydrobromide (GH) in bulk and pharmaceutical formulation. First method is zero order UV spectrophotometry and second is 1st derivative zero crossing spectrophotometry. The developed methods have shown best results in terms of linearity, accuracy, precision, LOD and LOQ for bulk drugs and marketed formulations. Absorbance was measured at 287 nm for zero order and 277.4 nm for first derivative. It obeyed Lambert-Beer’s law in the range of 30-80 μg mL-1. Both methods have good linearity (r2 = 0.9997) and accuracy found to be 100.5% and 101.2% for both methods respectively.
文摘The combined derivative spectrophotometry developed in this paper is a new method, which can be used to determine multicomporent mixture simultaneously and may improve the sensitivity and accuracy of the measurement remarkably. Two practical tests were carried out to verify the correctness of the theory, and the results are satisfactory.
文摘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.
文摘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%.
基金Project (No. 20276064) supported by the National Natural Science Foundation of China
文摘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.
文摘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.
基金supported by grants from the PetroChina-CUP Major Strategic Cooperation Projects(ZLZX2020010805,ZLZX2020020405)National Natural Science Foundation of China(41373086)+3 种基金National Science and Technology Major Project(No.2016ZX05050011,2016ZX05040002)Beijing Nova Program and Leading Talent Culturing Cooperative Projects(No.Z161100004916033)Beijing Higher Education Young Elite Teacher Project(No.YETP0670)Outstanding Young Excellent Teachers Foundation of China University of Petroleum(Beijing)(KYJJ2012-01-10).
文摘DNA analysis is the core of biotechnology applied in petroleum resources and engineering. Traditionally accurate determination of DNA purity and concentration by spectrometer is the first and critical step for downstream molecular biology research. In this study, three different spectrophotometry methods, BPM, NDTT and NPMTTZ were compared for their performance in determining DNA concentration and purity in 32 oil samples, and molecule methods like quantitative real-time PCR (qPCR) and high-throughput sequence were also performed to help assess the accuracy of the three methods in determining DNA concentration and purity. For ordinary heavy oil (OHO), extra heavy oil (EHO) and super heavy oil (SHO), the characteristics of high viscosity (η), density (ρ) and resin plus asphaltene content will affect the DNA extraction and UV determination. The DNA concentration was decreased as density increased: OHO (11.46 ± 18.34 ng/μL), EHO (6.68 ± 9.67 ng/μL) and SHO (6.20 ± 7.83 ng/μL), and the DNA purity was on the reverse: OHO (1.31 ± 0.27), EHO (1.54 ± 0.20), and SHO (1.83 ± 0.32). The results suggest that spectrophotometry such as BPM and NPMTTZ are qualitatively favorite methods as the quick non-consumable methods in determining DNA concentration and purity of medium oil and heavy oil.
基金financially supported by the National Natural Science Foundation of China(Nos.21765015,21808099,21765018)the Jiangxi Province Food and Drug Administration Science Foundation,China(No.2016SP04)
文摘A kind of sensitive, rapid, and simple spectrophotometry based on a Ytterbium(Yb3+) functionalized gold nanoparticle(Au NPs-Yb) was developed for detection of organophosphorus pesticides(OPs). Prepared AuNPs possess oxygen-containing functional groups and strong complexation reaction with Yb3+. While oxygen-containing thiophosphate in the OPs molecule can combine with Yb3+as a cross-linking molecule to produce insoluble yetterbium phosphate, resulting in the aggregation of AuNPs and great decrease in ultraviolet absorbance strength at 520 nm by ultraviolet visible(UV-vis) spectrophotometer. Under the optimized conditions, a linear relationship between the absorbance of AuNPs and OPs concentration ranged from 0.05 μg/L to 6.0 μg/L with limit of detection for 0.03 μg/L(S/N = 3), which is far lower than the maximum residue limit(0.01 ppm) in the European Union pesticides database. Therefore, this assay has potential application in the determination of OPs in the field of environmental and food monitoring.
文摘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）.
文摘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.
基金supported by the National Natural Science Foundation of China (No. 51273172)
文摘A new dual-wavelength dual-indicator catalytic kinetic spectrophotometric method for the determination of trace Ru(III)was studied.This method was based on Ru(III)-catalyzing oxidation of Arsenazo I and indigo carmine by potassium bromate in sulfuric acid.The absorbances of the catalytic and noncatalytic systems were measured at 510 and610 nm,respectively.Under the optimum conditions,the linear range of determination is 0–0.12 lgáml-1and the detection limit is 1.21 9 10-4lgáml-1.The method was applied for the determination of trace Ru(III)in ore samples with satisfactory results.
基金Supported by the Fund of Changchun Jilin University Little Swan Instrument Co.,Ltd.,China(No.GDYQ 2009-201SP)
文摘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.
基金Project supported by the National Natural Science Foundation of China(22276097,21976081)the Major Scientificand Technological Project of Bingtuan(2018AA002)。
文摘CeO_(2)-based catalysts are widely investigated for selective catalytic reduction(SCR)of NO with NH3.Interaction of NO/O_(2) with CeO_(2) generally produces two surface species,i.e.,nitrates and nitrites.However,the explicit quantification of these two species is still unresolved.Herein,we reported that spectrophotometry characterization was effective in determining surface adsorbed NOx species on CeO_(2) by measuring the corresponding ions(NO_(2)-and NO_(3)^(-))dissolved in aqueous solution.Experimental results show that both nitrate(-NO_(3))and nitrite(-NO_(2))species can be quantitatively evaluated and the accuracy is verified by calibrating with NOx-TPD result.Exclusive transfer of adsorbed NOx from catalyst surface to aqueous solution is confirmed and the dissolution process can be accelerated by ultrasonic treatment.Moreover,useful information related to evolution of surface NOx species under various conditions(O_(2) treatment,different adsorption temperature and duration)and over different catalysts(Fe_(2)O_(3),MnO_(2) and MnOx—CeO_(2))are provided.The result of present study demonstrates the potential of spectrophotometry for quantitative discrimination of surface NOx species on CeO_(2) and other oxide-based materials,which is conducive to mechanism analysis of SCR reaction.
基金supported by Guizhou Provincial Science and Technology Foundation (Qian Sci.Co.ZK[2021] No.198)Doctoral Research Startup Project in 2017 of Guizhou Normal University in China+1 种基金the B-type Strategic Priority Program of the Chinese Academy of Sciences (Grant No.XDB41000000)the National Natural Science Foundation of China (41872046,41173074 and 42063008)。
文摘While engineered nanoparticles are widely used and maybe eventually released into the environment,natural nanoparticles are also commonly found in the Earth system.Nanoparticles may critically affect the geochemical migration of associated elements and pose potential threats to the ecological environment.It is necessary to establish an accurate and reliable method for measuring the concentration of nanoparticles.AAS is one of the most commonly used methods for the concentration determination of nanoparticles.However,till now,there has been no systematic report on how experimental variables affect AAS measurements.In this study,we used gold nanoparticles(AuNPs) as an example and studied the influences of a list of factors on the concentration determination of AuNPs by AAS,including digestion method,ionization interference,acidic medium,background correction method,and organic matter.We demonstrate that all these factors may have varying degrees of influence on the measured gold concentrations.When the gold colloid is digested at room temperature for more than 8 h or at 60℃ for more than 2 h,and the system contains a low concentration of organic matter,AAS can accurately measure the AuNP concentration at ppm-level.The deuterium lamp background deduction method is not recommended to use for samples with lower gold concentrations.
文摘A rapid, reliable and accurate method for the determination of hexavalent chromium in Portland cement is developed. The proposed method includes direct spectrophotometric determination of Cr (VI) in Portland cement with 1, 2, 5, 8 Tetrahydroxyanthraquinone, (Quinalizarin, QINZ) at pH 1.5. The European Directive (2003/53/EC) limits the use of cements so that it contains no more than 2 mg.Kg-1 of water-soluble Cr (VI). The absorbance at 565 nm due to Cr (VI)-QINZ complex is recommended for the determination of water-soluble Cr (VI) in Portland cement. The quantification of Cr (VI) released from cement when mixed with water is performed according to TRGS 613 (Technical Rules of Hazardous Substances). The validity of the method is thoroughly examined and the proposed method gives satisfactory results. A derivative spectrophotometric method has been developed for the determination of total Cr (VI) in Portland cement in the presence of Fe (III) and Ti (IV). The hexavalent chromium complex formed at pH 1.5 allows precise and accurate determination of chromium (VI) over the concentration range 0.05 to 3.0 mg.L-1of chromium (VI). The validity of the method was examined by analyzing several Standard Reference Material (SRM) Portland cement samples. The MDL (at 95% confidence level) was found to be 25 ng/mL for chromium (VI) in National Institute of Standards and Technology (NIST) cement samples using the proposed method.
基金This work was supported by the Science Foundation of the Education Department of Zhejiang Province( 20000064).
文摘Ridge regression spectrophotometry(LHG)is used for thesimultaneous determination of five components(acetaminophen,p-aminophenol, caffeine, chlorphenamine maleate and guaifenesin)incough syr- up. The computer program of LHG is based on VB language.The difficulties in overlapping of absorption spectrums of fivecompounds are overcome by this procedure. The experimental resultsshow that the recovery of each component is in the range from97.9/100 to 103.3/100 and each component obtains satisfactory resultswithout any pre-separation.
