Copper-based azide(Cu(N_(3))2 or CuN_(3),CA)chips synthesized by in-situ azide reaction and utilized in miniaturized explosive systems has become a hot research topic in recent years.However,the advantages of in-situ ...Copper-based azide(Cu(N_(3))2 or CuN_(3),CA)chips synthesized by in-situ azide reaction and utilized in miniaturized explosive systems has become a hot research topic in recent years.However,the advantages of in-situ synthesis method,including small size and low dosage,bring about difficulties in quantitative analysis and differences in ignition capabilities of CA chips.The aim of present work is to develop a simplified quantitative analysis method for accurate and safe analysis of components in CA chips to evaluate and investigate the corresponding ignition ability.In this work,Cu(N_(3))2 and CuN_(3)components in CA chips were separated through dissolution and distillation by utilizing the difference in solubility and corresponding content was obtained by measuring N_(3)-concentration through spectrophotometry.The spectrophotometry method was optimized by studying influencing factors and the recovery rate of different separation methods was studied,ensuring the accuracy and reproducibility of test results.The optimized method is linear in range from 1.0-25.0 mg/L,with a correlation coefficient R^(2)=0.9998,which meets the requirements of CA chips with a milligram-level content test.Compared with the existing ICP method,component analysis results of CA chips obtained by spectrophotometry are closer to real component content in samples and have satisfactory accuracy.Moreover,as its application in miniaturized explosive systems,the ignition ability of CA chips with different component contents for direct ink writing CL-20 and the corresponding mechanism was studied.This study provided a basis and idea for the design and performance evaluation of CA chips in miniaturized explosive systems.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
[Objectives] To establish a determination method for the content of total lignanoids in Tangjiangshenkang granules. [Methods] Two-wavelength ultraviolet spectrophotometry (TWBS) was used to scan arctiin control soluti...[Objectives] To establish a determination method for the content of total lignanoids in Tangjiangshenkang granules. [Methods] Two-wavelength ultraviolet spectrophotometry (TWBS) was used to scan arctiin control solution, chlorogenic acid control solution and Tangjiangshenkang granule test solution in the range of 200-400 nm. In the ultraviolet scanning diagram of arctiin reference solution, the maximum absorption wavelength of 280 nm was determined as the determination wavelength λ 1, the detection wavelength in the ultraviolet scanning diagram of chlorogenic acid reference solution ( λ 1=280 nm) was determined, and 350 nm was the reference wavelength λ 2;the content of total lignosides in Tangjiangshenkang granules was determined with arctiin as the reference substance. [Results] The precision, accuracy, and durability of this method were fine. The concentration of arctiin was linearly correlated with the absorbance difference in the range of 0.007 95-0.071 55 mg/mL ( r =0. 999 9). The average recovery of arctiin was 100.8%, and the RSD value was 1.04% ( n =6). Calculated as arctiin, three batches of Tangjiangshenkang granules contain no less than 20% of total lignosides. [Conclusions] The method has the advantages of simple operation, good accuracy, precision and reliable stability. It can be used as the content determination and quality control method of total lignosides in Tangjiangshenkang granules.展开更多
The current work imitates the trivial method which intricates the abstraction along with classification of caffeine accessible in variability of decoction shrubberies which are expended in two different states of Indi...The current work imitates the trivial method which intricates the abstraction along with classification of caffeine accessible in variability of decoction shrubberies which are expended in two different states of India (Telengana & Uttar Pradesh). As per observation individuals of both the states are identical tender of consumption of tea. Abstraction progression tangled variability of stages which are discoursed in the work. In addition, the outcome of drinking of caffeine or the permitted ingestion of caffeine over tea has also been conferred through the work and linked the data with the literature data. In this study, we used a UV-visible spectrophotometer as well as liquid-liquid extraction method to determine the caffeine content in various tea samples. The significance of this study lies in the fact that accurate determination of caffeine content is essential for quality control and labeling of tea products. The UV-visible spectrophotometer method was found to be simple, reliable, and sensitive for the detection of caffeine in tea samples.展开更多
A highly sensitive spectrophotometric method for the determination of siliconwas developed.In the presence of aliphatic alcohol ethoxyehther(AEO-9),theoptimum condition for quantitative formation of the ion-associat...A highly sensitive spectrophotometric method for the determination of siliconwas developed.In the presence of aliphatic alcohol ethoxyehther(AEO-9),theoptimum condition for quantitative formation of the ion-association complexof siliconvanadomolybdate blue-Rhodamine 6G in aqueous phase was investigated,The maximum absorption wavelength of the complex was 556 nm.The apparentmolar absorptivity was 2.07×10<sup>5</sup> 1 mol<sup>-1</sup> cm<sup>-1</sup> at 556 nm and Beer’s law wasobeyed in the solution of silicon with concentrations from O to 2.0μg/25ml,This method has been applied to the determination of the amounts of trace siliconin different water samples with satisfactory results.展开更多
BACKGROUND: The indocyanine green (ICG) clearance test (clearance rate (K) and retention rate at 15 minutes (R(15))) is a sensitive indicator to evaluate liver function. The model for end-stage liver disease (MELD) sc...BACKGROUND: The indocyanine green (ICG) clearance test (clearance rate (K) and retention rate at 15 minutes (R(15))) is a sensitive indicator to evaluate liver function. The model for end-stage liver disease (MELD) score has emerged as a useful tool for estimating the mortality of patients awaiting liver transplantation and has recently been validated on patients with liver diseases of various etiologies and severity. In this study, we investigated the correlation between the ICG clearance test and MELD score of patients with liver cirrhosis. METHODS: From June 2007 to March 2008, 52 patients with liver cirrhosis admitted to our center were classified into Child-Pugh class A (8 patients), B (14) and C (30). The ICG clearance test (K value and R(15)) was performed by ICG pulse spectrophotometry (DDG-3300K), and the MELD scores of patients were calculated. RESULTS: As the Child-Pugh classification of liver function gradually deteriorated, the K value decreased, while R(15) and MELD score increased. There were significant statistical differences in K value, R(15) and MELD score in patients with different Child-Pugh classifications. Significant correlations were found between the parameters of the ICG clearance test (K value and R(15)) and MELD score. A negative correlation was observed between K value and MELD score (r=-0.892, P < 0.05), while a positive correlation was observed between R(15) and MELD score (r=0.804, P < 0.05). CONCLUSIONS: The ICG clearance test and MELD score are good parameters for evaluating liver function. Moreover, K value and R(15) have significant correlations with MELD score, especially the K value, which may be a convenient and appropriate indicator to evaluate liver function of patients with liver cirrhosis.展开更多
Arsenazo M could bind with bovine serum albumin to form a complex in Clark-Lube buffer at pH 2.3 and room temperature, which gives a maximum absorption peak at 625 nm with a red shift of 75 nm compared with that of Ar...Arsenazo M could bind with bovine serum albumin to form a complex in Clark-Lube buffer at pH 2.3 and room temperature, which gives a maximum absorption peak at 625 nm with a red shift of 75 nm compared with that of Arsenazo M itself. The apparent molar absorptivity of the BSA-Arsenazo M complex is 3.21105 Lmol-1cm-1. The linear ranges for protein determination are wide (at least 0-100 mg/mL).展开更多
Dynamic microwave-assisted extraction(DMAE) of flavonoids from Radix Scutellarie was described in this article. A TM010 microwave resonant cavity was used as the energy coupler. Several parameters of DMAE, including...Dynamic microwave-assisted extraction(DMAE) of flavonoids from Radix Scutellarie was described in this article. A TM010 microwave resonant cavity was used as the energy coupler. Several parameters of DMAE, including concentration, flow rate, volume of the extraction solvent, and irradiation power, were optimized. The extraction was performed under the optimum conditions for the extraction of total flavonoids. The total flavonoids were determined by UV-Vis spectrophotometry. The main bioactive components, including baicalin, baicalein, and wogonin, were determined by HPLC. The extraction yields of the tlavonoids obtained by DMAE were compared with those obtained by pressurized microwave assisted extraction ( PMAE), ultrasonic extraction ( UE ), soxhlet extraction ( SE ), and reflux extraction( RE), and these results indicate that DMAE is a good alternative method for the extraction of flavonoids from Radix Scutellade.展开更多
In the medium of 0.18~1.08 mol·L^(-1) sulfuric acid, cerium(Ⅳ) has the color-fading effect on DBC-arsenazo. The apparent molar absorptivity of the color-fading reaction is ε _(530 nm)=1.03×10~4 L·mo...In the medium of 0.18~1.08 mol·L^(-1) sulfuric acid, cerium(Ⅳ) has the color-fading effect on DBC-arsenazo. The apparent molar absorptivity of the color-fading reaction is ε _(530 nm)=1.03×10~4 L·mol^(-1)·cm^(-1). Beer′s law is obeyed over the range of 1.20~12.0 μg·ml^(-1) of Ce (Ⅳ) which shows a linear relationship with the decrease in the absorbance of the colored solution. The effect of thirty-six coexisting ions was studied. The method was applied to the determination of the trace amount of cerium in water samples and has the advantage of high accuracy and good selectivity.展开更多
A simple and sensitive spectrophotometric method was described for the determination of cerium(IV) based on its catalytic effect on the oxidation of naphthol green B by potassium periodate in the medium of sulfuric ...A simple and sensitive spectrophotometric method was described for the determination of cerium(IV) based on its catalytic effect on the oxidation of naphthol green B by potassium periodate in the medium of sulfuric acid. The influences of acidity, concentration of reactants, reaction time, reaction temperature, and foreign ions were discussed, and the optimum reaction conditions were established. The reaction was monitored spectrophotometrieally by measuring the decrease in absorbance of naphthol green B at 710 nm after a fixed time (8 min). The proposed method allowed the determination of cerium(IV) in the range of 0.08-2.4 μg·mL^-1 with good precision and accuracy, and the detection limit was 0.012 μg·mL^-1. The method was applied successfully for the determination of trace cerium in hair samples without previous separation. Recovery experiments were also performed, and the recovery was between 95.7%-111.0%.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
In this paper, 2-(2-imidazolylazo)-5-diethylami phenol (IZAPN) was prepared, theprotonation behaviour and the condition of spectrophotometric determination of cobalt with thisreagent are reported. The results show tha...In this paper, 2-(2-imidazolylazo)-5-diethylami phenol (IZAPN) was prepared, theprotonation behaviour and the condition of spectrophotometric determination of cobalt with thisreagent are reported. The results show that the new colour reagent reacts with cobalt to from astable purple red complex (l:3). However, the complex formed could be changed into anotherspecies with stable absorptivity by addition of mineral acid (1+1). The, method is highly selectiveand sensitive and has been applied to the direct determination of cobalt in some alloys withsatisfactory results.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 sensitive and selective kinetic spectrophotometric method for the determination of V(V) was developed based on the catalytic oxidation of thionine by KBIO3 in 0.6 mol·L^-1 HaPO4 medium. The linear calibration...A sensitive and selective kinetic spectrophotometric method for the determination of V(V) was developed based on the catalytic oxidation of thionine by KBIO3 in 0.6 mol·L^-1 HaPO4 medium. The linear calibration range and detection limit at 25℃ were 0-0.5 μg·mL^-1 and 0.01 μg·mL^-1, respectively. In the presence of NaF and urea, most of the common ions did not interfere with the determination of V(V). The proposed method was applied for the determination of vanadium in steels and satisfactory results were obtained.展开更多
To study the relationship between the late postmortem interval (PMI) and trimethyl-amine-nitrogen (TMA-N) in postmortem tissues of cadaver, TMA-N in muscles, livers and kidneys of rats was measured at different po...To study the relationship between the late postmortem interval (PMI) and trimethyl-amine-nitrogen (TMA-N) in postmortem tissues of cadaver, TMA-N in muscles, livers and kidneys of rats was measured at different postmortem intervals (PMI) by using a modified spectrophotometric method. The results indicated that the detection sensitivity of TMA-N was 1 mg/L, and there was a good linear correlation between the value of absorbance (A value) and TMA-N at the concentration of 1-10 mg/L (R2=0.9991). Although TMA variation in muscles was different from that in inner organs during the time since death, TMA-N changes in cadaver tissues was positively correlated with PMI. During 2 to 7d since death, the best correlation between PMI and TMA-N concentration was found in muscles. With PMI as an independent variable, the cubic polynomial regression equation was y=-0.457x3 +6.519x2-24.574x+27.207 (R2=0.969). During 3 to 8 days since death, PMI was best correlated with TMA-N concentration in inner organs. With PMI as the independent variable, the cubic polynomial regression equation was y=0.509x3-9.153x2+55.727x-95.819 (R2=0.953). It was concluded that TMA-N in tissues could be used as a new estimator for late PMI. The method used in this study offered advantages such as accuracy, sensitivity, little samples required and wide PMI estimation.展开更多
A novel method for the determination of captopril by spectrophotometer is described in this paper. The experiment is based on the fact that Fe(Ⅲ) is reduced to Fe(Ⅱ) by captopril, then the in sire formed Fe(Ⅱ...A novel method for the determination of captopril by spectrophotometer is described in this paper. The experiment is based on the fact that Fe(Ⅲ) is reduced to Fe(Ⅱ) by captopril, then the in sire formed Fe(Ⅱ) reacts with potassium ferricyanide to give the soluble prussian blue at pH 4.00, and its maximal adsorption wavelength (λmax) is 735 nm. Good linear relationship is obtained between the absorbance and the concentration of captopril in the wide range of 0.05-20 μg/mL. The linear regression equation is A = -0.04314 + 0.11423C (μg/mL) with a correlation coefficient R = 0.9998. The detection limit (3σ/k) is 0.04 μg/mL, the molar absorption coefficient is 2.5×10^4 L/mol cm. By mensurating the absorbance of soluble prussian blue, the indirect determination of captopril can be obtained. This method has been successfully applied to determination of captopril in pharmaceutical samples. Analytical results obtained are satisfactory.展开更多
基金the financial support provided by the National Natural Science Foundation of China(Grant No.11872013).
文摘Copper-based azide(Cu(N_(3))2 or CuN_(3),CA)chips synthesized by in-situ azide reaction and utilized in miniaturized explosive systems has become a hot research topic in recent years.However,the advantages of in-situ synthesis method,including small size and low dosage,bring about difficulties in quantitative analysis and differences in ignition capabilities of CA chips.The aim of present work is to develop a simplified quantitative analysis method for accurate and safe analysis of components in CA chips to evaluate and investigate the corresponding ignition ability.In this work,Cu(N_(3))2 and CuN_(3)components in CA chips were separated through dissolution and distillation by utilizing the difference in solubility and corresponding content was obtained by measuring N_(3)-concentration through spectrophotometry.The spectrophotometry method was optimized by studying influencing factors and the recovery rate of different separation methods was studied,ensuring the accuracy and reproducibility of test results.The optimized method is linear in range from 1.0-25.0 mg/L,with a correlation coefficient R^(2)=0.9998,which meets the requirements of CA chips with a milligram-level content test.Compared with the existing ICP method,component analysis results of CA chips obtained by spectrophotometry are closer to real component content in samples and have satisfactory accuracy.Moreover,as its application in miniaturized explosive systems,the ignition ability of CA chips with different component contents for direct ink writing CL-20 and the corresponding mechanism was studied.This study provided a basis and idea for the design and performance evaluation of CA chips in miniaturized explosive systems.
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Supported by Major Science and Technology Project"Major New Drug Innovation".
文摘[Objectives] To establish a determination method for the content of total lignanoids in Tangjiangshenkang granules. [Methods] Two-wavelength ultraviolet spectrophotometry (TWBS) was used to scan arctiin control solution, chlorogenic acid control solution and Tangjiangshenkang granule test solution in the range of 200-400 nm. In the ultraviolet scanning diagram of arctiin reference solution, the maximum absorption wavelength of 280 nm was determined as the determination wavelength λ 1, the detection wavelength in the ultraviolet scanning diagram of chlorogenic acid reference solution ( λ 1=280 nm) was determined, and 350 nm was the reference wavelength λ 2;the content of total lignosides in Tangjiangshenkang granules was determined with arctiin as the reference substance. [Results] The precision, accuracy, and durability of this method were fine. The concentration of arctiin was linearly correlated with the absorbance difference in the range of 0.007 95-0.071 55 mg/mL ( r =0. 999 9). The average recovery of arctiin was 100.8%, and the RSD value was 1.04% ( n =6). Calculated as arctiin, three batches of Tangjiangshenkang granules contain no less than 20% of total lignosides. [Conclusions] The method has the advantages of simple operation, good accuracy, precision and reliable stability. It can be used as the content determination and quality control method of total lignosides in Tangjiangshenkang granules.
文摘The current work imitates the trivial method which intricates the abstraction along with classification of caffeine accessible in variability of decoction shrubberies which are expended in two different states of India (Telengana & Uttar Pradesh). As per observation individuals of both the states are identical tender of consumption of tea. Abstraction progression tangled variability of stages which are discoursed in the work. In addition, the outcome of drinking of caffeine or the permitted ingestion of caffeine over tea has also been conferred through the work and linked the data with the literature data. In this study, we used a UV-visible spectrophotometer as well as liquid-liquid extraction method to determine the caffeine content in various tea samples. The significance of this study lies in the fact that accurate determination of caffeine content is essential for quality control and labeling of tea products. The UV-visible spectrophotometer method was found to be simple, reliable, and sensitive for the detection of caffeine in tea samples.
文摘A highly sensitive spectrophotometric method for the determination of siliconwas developed.In the presence of aliphatic alcohol ethoxyehther(AEO-9),theoptimum condition for quantitative formation of the ion-association complexof siliconvanadomolybdate blue-Rhodamine 6G in aqueous phase was investigated,The maximum absorption wavelength of the complex was 556 nm.The apparentmolar absorptivity was 2.07×10<sup>5</sup> 1 mol<sup>-1</sup> cm<sup>-1</sup> at 556 nm and Beer’s law wasobeyed in the solution of silicon with concentrations from O to 2.0μg/25ml,This method has been applied to the determination of the amounts of trace siliconin different water samples with satisfactory results.
文摘BACKGROUND: The indocyanine green (ICG) clearance test (clearance rate (K) and retention rate at 15 minutes (R(15))) is a sensitive indicator to evaluate liver function. The model for end-stage liver disease (MELD) score has emerged as a useful tool for estimating the mortality of patients awaiting liver transplantation and has recently been validated on patients with liver diseases of various etiologies and severity. In this study, we investigated the correlation between the ICG clearance test and MELD score of patients with liver cirrhosis. METHODS: From June 2007 to March 2008, 52 patients with liver cirrhosis admitted to our center were classified into Child-Pugh class A (8 patients), B (14) and C (30). The ICG clearance test (K value and R(15)) was performed by ICG pulse spectrophotometry (DDG-3300K), and the MELD scores of patients were calculated. RESULTS: As the Child-Pugh classification of liver function gradually deteriorated, the K value decreased, while R(15) and MELD score increased. There were significant statistical differences in K value, R(15) and MELD score in patients with different Child-Pugh classifications. Significant correlations were found between the parameters of the ICG clearance test (K value and R(15)) and MELD score. A negative correlation was observed between K value and MELD score (r=-0.892, P < 0.05), while a positive correlation was observed between R(15) and MELD score (r=0.804, P < 0.05). CONCLUSIONS: The ICG clearance test and MELD score are good parameters for evaluating liver function. Moreover, K value and R(15) have significant correlations with MELD score, especially the K value, which may be a convenient and appropriate indicator to evaluate liver function of patients with liver cirrhosis.
文摘Arsenazo M could bind with bovine serum albumin to form a complex in Clark-Lube buffer at pH 2.3 and room temperature, which gives a maximum absorption peak at 625 nm with a red shift of 75 nm compared with that of Arsenazo M itself. The apparent molar absorptivity of the BSA-Arsenazo M complex is 3.21105 Lmol-1cm-1. The linear ranges for protein determination are wide (at least 0-100 mg/mL).
基金the Development Program of the Science and Technology Department of Jilin Province(No20050560)
文摘Dynamic microwave-assisted extraction(DMAE) of flavonoids from Radix Scutellarie was described in this article. A TM010 microwave resonant cavity was used as the energy coupler. Several parameters of DMAE, including concentration, flow rate, volume of the extraction solvent, and irradiation power, were optimized. The extraction was performed under the optimum conditions for the extraction of total flavonoids. The total flavonoids were determined by UV-Vis spectrophotometry. The main bioactive components, including baicalin, baicalein, and wogonin, were determined by HPLC. The extraction yields of the tlavonoids obtained by DMAE were compared with those obtained by pressurized microwave assisted extraction ( PMAE), ultrasonic extraction ( UE ), soxhlet extraction ( SE ), and reflux extraction( RE), and these results indicate that DMAE is a good alternative method for the extraction of flavonoids from Radix Scutellade.
文摘In the medium of 0.18~1.08 mol·L^(-1) sulfuric acid, cerium(Ⅳ) has the color-fading effect on DBC-arsenazo. The apparent molar absorptivity of the color-fading reaction is ε _(530 nm)=1.03×10~4 L·mol^(-1)·cm^(-1). Beer′s law is obeyed over the range of 1.20~12.0 μg·ml^(-1) of Ce (Ⅳ) which shows a linear relationship with the decrease in the absorbance of the colored solution. The effect of thirty-six coexisting ions was studied. The method was applied to the determination of the trace amount of cerium in water samples and has the advantage of high accuracy and good selectivity.
基金supported by the Natural Sci-ence Foundation of Shandong Province, China (No. Y2008B26)
文摘A simple and sensitive spectrophotometric method was described for the determination of cerium(IV) based on its catalytic effect on the oxidation of naphthol green B by potassium periodate in the medium of sulfuric acid. The influences of acidity, concentration of reactants, reaction time, reaction temperature, and foreign ions were discussed, and the optimum reaction conditions were established. The reaction was monitored spectrophotometrieally by measuring the decrease in absorbance of naphthol green B at 710 nm after a fixed time (8 min). The proposed method allowed the determination of cerium(IV) in the range of 0.08-2.4 μg·mL^-1 with good precision and accuracy, and the detection limit was 0.012 μg·mL^-1. The method was applied successfully for the determination of trace cerium in hair samples without previous separation. Recovery experiments were also performed, and the recovery was between 95.7%-111.0%.
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In this paper, 2-(2-imidazolylazo)-5-diethylami phenol (IZAPN) was prepared, theprotonation behaviour and the condition of spectrophotometric determination of cobalt with thisreagent are reported. The results show that the new colour reagent reacts with cobalt to from astable purple red complex (l:3). However, the complex formed could be changed into anotherspecies with stable absorptivity by addition of mineral acid (1+1). The, method is highly selectiveand sensitive and has been applied to the direct determination of cobalt in some alloys withsatisfactory results.
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%.
文摘A sensitive and selective kinetic spectrophotometric method for the determination of V(V) was developed based on the catalytic oxidation of thionine by KBIO3 in 0.6 mol·L^-1 HaPO4 medium. The linear calibration range and detection limit at 25℃ were 0-0.5 μg·mL^-1 and 0.01 μg·mL^-1, respectively. In the presence of NaF and urea, most of the common ions did not interfere with the determination of V(V). The proposed method was applied for the determination of vanadium in steels and satisfactory results were obtained.
基金supported by a grant from the Health Department of Hubei Province (No. JX2B02).
文摘To study the relationship between the late postmortem interval (PMI) and trimethyl-amine-nitrogen (TMA-N) in postmortem tissues of cadaver, TMA-N in muscles, livers and kidneys of rats was measured at different postmortem intervals (PMI) by using a modified spectrophotometric method. The results indicated that the detection sensitivity of TMA-N was 1 mg/L, and there was a good linear correlation between the value of absorbance (A value) and TMA-N at the concentration of 1-10 mg/L (R2=0.9991). Although TMA variation in muscles was different from that in inner organs during the time since death, TMA-N changes in cadaver tissues was positively correlated with PMI. During 2 to 7d since death, the best correlation between PMI and TMA-N concentration was found in muscles. With PMI as an independent variable, the cubic polynomial regression equation was y=-0.457x3 +6.519x2-24.574x+27.207 (R2=0.969). During 3 to 8 days since death, PMI was best correlated with TMA-N concentration in inner organs. With PMI as the independent variable, the cubic polynomial regression equation was y=0.509x3-9.153x2+55.727x-95.819 (R2=0.953). It was concluded that TMA-N in tissues could be used as a new estimator for late PMI. The method used in this study offered advantages such as accuracy, sensitivity, little samples required and wide PMI estimation.
文摘A novel method for the determination of captopril by spectrophotometer is described in this paper. The experiment is based on the fact that Fe(Ⅲ) is reduced to Fe(Ⅱ) by captopril, then the in sire formed Fe(Ⅱ) reacts with potassium ferricyanide to give the soluble prussian blue at pH 4.00, and its maximal adsorption wavelength (λmax) is 735 nm. Good linear relationship is obtained between the absorbance and the concentration of captopril in the wide range of 0.05-20 μg/mL. The linear regression equation is A = -0.04314 + 0.11423C (μg/mL) with a correlation coefficient R = 0.9998. The detection limit (3σ/k) is 0.04 μg/mL, the molar absorption coefficient is 2.5×10^4 L/mol cm. By mensurating the absorbance of soluble prussian blue, the indirect determination of captopril can be obtained. This method has been successfully applied to determination of captopril in pharmaceutical samples. Analytical results obtained are satisfactory.