Rapid accuracy determining DNA purity and concentration in heavy oils by spectrophotometry methods

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.

Determination of Total Lignanoids in Tangjiangshenkang Granules by Two-Wavelength Ultraviolet Spectrophotometry

[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.

Estimation of the galanthamine using derivative spectrophotometry in bulk drug and formulation

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.

Studies on the Combined Derivative Spectrophotometry

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.

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.

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%.

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.

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）.

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.

Dual-wavelength dual-indicator catalytic kinetic spectrophotometry for determination of trace Ru(Ⅲ)

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.

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.

The Simultaneous Determination of Five Components Including Acetaminophen by Ridge Regression Spectrophotometry

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.

Determination of Trace Amount of Yttrium with Bromopyrogallol Red by solid-phase Spectrophotometry

A simple and sensitive method for the determination of trace amount of yttrium by solid-phase spectrophotometry has been studied. Yttrium can form a 1 : 1 complex with bromopyrogallol red (BPR) on resin, which was determined directly at 605 nm, pH=6.5. It has a highly sensitivity (epsilon = 6.3 x 10(6)) which is 300-fold higher than the corresponding spectrophotometry in solution. The method was applied to the determination of yttrium in churchite.

Spectrophotometric Determination of Water-Soluble Hexavalent Chromium and Determination of Total Hexavalent Chromium Content of Portland Cement in the Presence of Iron (III) and Titanium (IV) Using Derivative Ratio Spectrophotometry

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.

Separation/Enrichment of Copper and Silver Using Titanium Dioxide Nanoparticles Coated with Poly-Thiophene and Their Analysis by Flame Atomic Absorption Spectrophotometry

We report on the use of titanium dioxide nanoparticles (NPs) coated with poly-thiophene for the preconcentration of copper and silverions. The NPs were prepared by first modifying the surface of TiO2 NPs with vinyl groups and then copolymerizing them with vinyl thiophen. The resulting TiO2-polythiophene core-shell NPs were characterized by thermogravimetry, differential thermal analysis, scanning electron microscopy, Fourier transform infrared spectrometry and X-ray diffraction. The experimental conditions such as pH value, adsorption and desorption time, type, concentration and volume of the eluent, break through volume, and effect of potentially interfering ions were optimized. The ions were then desorbed with hydrochloric acid and determined by FAAS. The limits of detection are 0.4 and 1.2 μg·L_1 for Cu(II) and Ag(I), respectively, and recoveries and precisions are >98.0%

Simultaneous Determination of Zirconium and Hafnium by Dual System and Dual Wavelength Spectrophotometry

A dual system and dual wavelength spectrophotometry (DSDWS) used to simultaneously determine Zr and Hf were proposed. Zr(Hf)-XO-CIMAB and Zr(Hf)-CAB-CDMAA-Triton X-100 were chosen as a pair of chromophoric systems. The difference of chromophoric behaviours between Zr and Hf is increased by the addition of hydrogen peroxide as masking agent and by adjustment of acidity. The apparent molar absorptivities of Zr and Hf are 2.0×105 and 5.0×104 L&middotmol-1&middotcm-1 respectively. The procedure is simple and rapid.

Determination of arsenic in air particulates and diesel exhaust particulates by spectrophotometry

A method was developed for the determination of trace arsenic by spectrophotometry. The proposed method is rapid, simple, and inexpensive. This method can be used for sensitive determination of trace arsenic in environmental samples and especially in air particulates. The results obtained by this method as a proposed method were compared with those obtained by hydride generation atomic absorption spectrometry as a popular reported method for the determination of arsenic and an excellent agreement was found between them. The method was also used for determination of arsenic associated with airborne particulate matter and diesel exhaust particulates. The results showed that considerable amount of arsenic are associated with diesel engine particulates. The variation in concentration of arsenic was also investigated. The atmospheric concentration of arsenic was different in different sampling stations was dependent to the traffic density.

Study on New Sensitive Method of Determination of Phosphorus by Solid Phase Spectrophotometry

The use of solid phase spectrophotometry for the determination of trace phosphorus in the system of phosphomolybdate-fructose is described. The adsorption of the system on anion-exchange resin is reported.

Concentration determination of gold nanoparticles by flame atomic absorption spectrophotometry

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.

Kinetic Investigation of Ce,Y-CPAmA Systems and Simultaneous Determination of Sc,Y,Ce via Complementary Tristimulus Spectrophotometry

In the past ten years the eomplementary tristimulus speetrophotometryll],eTs,has seen its diverse appli-eations{2一61 though most researehes remain in relatively simpe systems,and less work has been involvinkinetie reaetions. An attemPt has been made on the investigation of some comPlieated systems eontainingrare earths and meta一acetylchloroPhosPhonaz