Preparation Of Sample Solution Research Articles

Iron Determination in Multivitamin Tablets: Enhancing Military Nutritional Preparedness Based Linear Regression Method

AAS is also an important method that has the most extensive application in metal analysis. most of the determinations were carried out by thin spectrophotometry, therefore an experiment was carried out to determine the Fe content in multivitamin tablets using the atomic absorption spectrophotometry method has high selectivity and sensitivity. Standard solution preparation. Prepare a standard solution of Fe with a concentration of 1, 2, 3, 4, and 5 ppm, then read the absorbance of the standard solution on AAS. Sample solution preparation and absorbance measurement. Several tablets were put into a beaker and 7 ml of concentrated HCl was added working principle of atomic absorption spectrophotometry is based on the evaporation of the sample solution which will initially be nebulized to form a spray, then it will be desolvated to form a dry aerosol until it is evaporated and converted into free atoms.. Iron levels in samples using AAS can be found by measuring the intensity of the radiation that decreases after being transmitted. The reduction in radiation intensity is proportional to the concentration of the sample element in the sample being measured. By testing the t-test, it was found that the AAS instrument was more sensitive to low concentrations

Evaluation and Validation of Carvedilol in Bulk and Pharmaceutical Dosage Forms

Background: Quality may be described as the character that determines the degree of excellence. A good quality medication is anything that meets the product specifications, can be purchased safely, and can be used confidently for the purpose for which it was designed.To obtain a high quality medication, the manufacturing process for producing a drug should have quality integrated into it. Analytical chemistry is the discipline that seeks ever better methods of assessing the chemical composition of natural and manmade materials.
 Aims and Objective: Evaluation and validation of carvedilol in bulk and pharmaceutical dosage forms.
 Material and Methods: preparation of standard stock solution and preparation of sample solution as per standard protocol.
 Result: In the RP-HPLC method, a wavelength of 242 nm was retained and the retention time was found to be 2.9 with optimised conditions. Carvedilol showed linearity in the range of 15.62 -93.75µg/ml. where the peak shape was symmetrical and a good correlation coefficient value was obtained.
 Conclusion: RP-HPLC, HPTLC, UV spectroscopy were found to be sensitive, precise, and accurate. However these three methods can be used for the routine analysis of carvedilol from formulation.

Determination of elemental impurities of Arsenic, Cadmium, Mercury, Lead and Palladium content in Testosterone propionate by using ICP-MS

The aim of the present work is to develop and establish a validated analytical method for the determination of arsenic, cadmium, mercury, lead and palladium content in testosterone propionate by using inductive coupled plasma mass spectroscopy (ICP-MS). Samples were analyzed after a preparation of sample solution by dissolving in suitable solvents of concentrated nitric acid and concentrated hydrochloric acid. In the present method, RF power of 1550 watts, RF matching is 1.80 V, nebulizer flow of 0.10 rps and plasma view at spectrum mode were used. Octopole conditions are He flow is on, He flow rate is 4.3 mL/min and energy discrimination is 3.0 V were used. Significant savings in sample volumes, reagents, analysis cost and time are realized. Arsenic, cadmium, mercury, lead and palladium are primary concerned due to their high toxicity and potential contaminants should be limited in testosterone propionate and the developed method was validated according to ICH and USP guidelines. The correlation coefficient, recovery rate, LOD and LOQ reached the acceptable limits. The validated method was selective, sensitive, rapid and capable of the determination of elemental impurities of arsenic, cadmium, mercury, lead and palladium content in bulk drugs.

Preparation of sample solutions using nanoimprint films for quantitative X-ray fluorescence analysis by thin film fundamental parameter method

Various sample preparation methods have been proposed for X-ray fluorescence analysis of mineral components in a liquid. Among them, the dry spot method is widely used; however, the issue is that the prepared dried residue is non-uniform. We developed nanoimprint films using the thermal nanoimprint method. A uniform and thin dry residue was prepared using the nanoimprint film. The thin film fundamental parameter method, a quantitative analysis method used in X-ray fluorescence analysis, was applied to dried residues to analyze their content. As a result, the analysis value was found to be close to the authentication and inductively coupled plasma atomic emission spectromy analysis values.

Virus Size Analysis by Gas-Phase Mobility Measurements: Resolution Limits.

Electrospraying (ES) dissolved viral particles, followed by charge reduction and size analysis with a differential mobility analyzer (DMA), offers a flexible size-analysis tool for small particles in solution. The technique relies on pioneering work by Kaufman and colleagues, commercialized by TSI, and often referred to as GEMMA. However, viral studies with TSI's GEMMA have suffered from limited resolving power, possibly because of imperfections in either the instrument (DMA or charge reduction) or the sample solution preparation. Here, we explore the limits of the resolution achievable by GEMMA, taking advantage of (i) cleaner charge reduction methods and (ii) DMAs of higher resolving power. Analysis of the literature provides indications that mobility peak widths (fwhm) of 2% or less may be achieved by combining careful sample preparation with improved instrumentation. Working with purified PP7 bacteriophage particles small enough to be classifiable by existing high-resolution DMAs, we confirm that fairly narrow viral mobility peaks may be obtained (relative full width at half-maximum fwhm <5%). Comparison of spectra of a given apian virus sample obtained with TSI's GEMMA and our improved instrumentation confirms that one critical limitation is the DMA. This is further verified by narrow peaks from murine parvovirus, norovirus, and encephalomyelitis virus samples, obtained in our improved GEMMA with little sample preparation, directly from infected cell cultures. Classification of purified large (60 nm) coliphage PR772 particles leads to broad peaks, due to both viral degradation and limited intrinsic resolution of the DMAs used to cover the range of such large particles. We conclude that improved DMAs suitable for high-resolution analysis of particles larger than 30 nm need to be developed to determine the intrinsic mobility width of viral particles.

ATOMIC ABSORPTION SPECTROPHOTOMETER – A VERSATILE TOOL FOR THE ESTIMATION OF NICKEL CONTENT IN DRONEDARONE

Objective: The present investigation is to develop a validated analytical method for the determination of nickel content in dronedarone hydrochloride bulk drug by atomic absorption spectrophotometer (AAS).&#x0D; Methods: Samples were analyzed after a preparation of sample solution by dissolving in suitable diluents of nitric acid and perchloric acid. In the present method, AAS with 0.2 nm slit width, nickel hollow cathode lamp with a wavelength of 232 nm has been employed.&#x0D; Results: The system suitability parameters were performed to assess the system performance. The limit of detection and limit of quantification (LOQ) were found to be 0.051 ppm and 0.15 ppm, respectively. The percentage recovery at LOQ, 50%, 100%, and 150% levels of nickel in dronedarone was found to be 95.55, 109.33, 96, and 97.55, respectively.&#x0D; Conclusion: With the developed method, the nickel content in dronedarone bulk sample was found to be 3.0 ppm.

Development of quantitative HPTLC-densitometry methods following a model process for transfer of TLC screening methods for pharmaceutical products containing moxifloxacin HCl, ofloxacin, amoxicillin trihydrate, acetylsalicylic acid + acetaminophen + caffeine, nimesulide, irbesartan, and pantoprazole

Transfer of thin-layer chromatography (TLC) Global Pharma Health Fund E.V. Minilab Manual and U.S. Food and Drug Administration (FDA) Compendium protocols for detecting falsified or substandard drugs in pharmaceutical products to quantitative high-performance TLC (HPTLC)-densitometry methods suitable for support of regulatory authorities was performed following a previously published model process for moxfloxacin HCl, ofloxacin, and amoxicillin trihydrate. In addition, the guidelines of the process were followed to develop and validate HPTLC-densitometry methods for pharmaceutical products containing acetylsalicylic acid + acetaminophen + caffeine, nimesulide, irbesartan, and pantoprazole that are not included in the Minilab Manual or FDA Compendium. The new methods involved silica gel 60 F254 plates; semiautomated bandwise sample and standard solution application; ascending mobile phase development of plates in a glass chamber; and automated slit scanning densitometry for detection, identification, and quantification. Data for standard and sample solution preparation, calibration curves, assay of pharmaceutical products compared to label declarations, standard addition validation, and peak purity and peak identity are provided. Supplemental FDA Compendium screening methods corresponding to the HPTLC-densitometry methods for caffeine, nimesulide, irbesartan, pantoprazole, and acetylsalicylic acid co-formulated with acetaminophen and caffeine were developed and published online with open access on the website www.layloff.net.

Development of a Sensitive HPTLC Method for Quantification of Nimbolide in Azadirachta indica and Its Dosage Form

An improved and sensitive High Performance Thin-Layer Chromatography (HPTLC) method has been developed for determination of anticancer compound, nimbolide in different parts of Azadirachta indica and its dosage form. A quick and simple ultrasonication technique was used for the preparation of sample solutions. Separation of the components was achieved on precoated TLC plates by using optimized tertiary mobile phase consisting of n-hexane:ethyl acetate:acetic acid (6:4:0.2, v/v/v) with a solvent migration distance of 68 mm. Densitometric quantification was performed after derivatization of the plate with methanol-sulfuric acid reagent in reflection/absorption mode at 515 nm. A linear response of nimbolide was obtained over the range of 200-1400 ng/spot with a correlation coefficient of r(2) = 0.99968, indicating good relationship between concentration and peak area. The method sensitivity was found to be increased by performing the analysis after derivatization with methanol-sulfuric acid reagent. The limit of detection and limit of quantification were found to be 70 and 200 ng/spot, respectively. The obtained recovery range from 96.70 to 98.01% with an average of 97.46% proves excellent accuracy of the method. ICH protocol was followed for validation of the HPTLC method in terms of precision, repeatability and accuracy. The developed method was found to be highly sensitive and the mobile phase efficiently separated nimbolide from other components. The maximum content of nimbolide was found in leaves. Further, the developed HPTLC method can be applied successfully for the marker evaluation of the formulations containing A. indica.

APPLICATION OF AN EXPANDED MODEL PROCEDURE FOR TRANSFER OF TLC SCREENING METHODS FOR SUBSTANDARD AND FAKE DRUGS DESIGNED FOR USE IN DEVELOPING COUNTRIES TO QUANTITATIVE HPTLC-DENSITOMETRY METHODS

Transfer of four rapid thin-layer chromatography (TLC) screening methods used to detect substandard and fake pharmaceutical products to quantitative high-performance TLC (HPTLC)-densitometry methods is demonstrated using an expanded version of a model procedure that was published earlier. These methods for mebendazole, diphenhydramine hydrochloride, amodiaquine, and artesunate are contained in a Compendium of methods by Kenyon and Layloff and/or Minilab method manuals from Global Pharma Health Fund E.V. for use in countries with limited resources. A new HPTLC-densitometry method was also developed for amitriptyline hydrochloride, for which there was no Compendium or Minilab method that could be transferred. These quantitative methods use Merck HPTLC silica gel 60 F254 glass plates, automated standard and sample solution application, and automated densitometry for detection, identification, and quantification. Standard and sample solution preparation and application procedures for obtaining calibration curves and bracketed samples are described. Additions to the previous model procedure include peak identity and purity checks by spectral comparison. HPTLC gives better efficiency, selectivity, and resolution than TLC, and the new methods overcome the deficiencies in technology related to manual application and visual zone comparison that do not allow the Compendium and Minilab TLC procedures to support regulatory compliance actions. These new methods can be fully validated according to International Conference on Harmonization (ICH) guidelines or by interlaboratory studies if their applications require.

A model procedure for the transfer of TLC pharmaceutical product screening methods designed for use in developing countries to quantitative HPTLC-densitometry methods

Summary Transfer of four rapid thin-layer chromatography (TLC) screening methods used to detect substandard and counterfeit pharmaceutical products to quantitative high-performance TLC (HPTLC)-densitometry methods is demonstrated. These methods for acetaminophen, acetylsalicylic acid, ibuprofen, and chlorpheniramine maleate are contained in a Compendium of methods developed by Kenyon and Layloff for use in countries with limited resources. The new quantitative methods use Merck HPTLC silica gel 60 F254 glass plates, automated standard and sample application, and automated densitometry for detection, identification, and quantification. Standard and sample solution preparation and application procedures for obtaining calibration curves and bracketed samples are described. The HPTLC plates give better efficiency, selectivity, and resolution than TLC, and the new methods overcome the deficiencies in technology related to manual application and visual zone comparison that do not allow the Compendium TLC proced...

Quantitative Determination of Metformin Hydrochloride in Tablet Formulation Containing Croscarmellose Sodium as Disintegrant by HPLC and UV Spectrophotometry

Purpose: To develop and validate a suitable method for the assay of metformin hydrochloride (HCl) in tablets containing croscarmellose sodium as an additive. Methods: Methanol and ethanol (99%) were assessed as solvents for sample preparation for the assay of metformin HCl in tablets containing croscarmellose sodium by high performance liquid chromatography (HPLC) and ultra violet spectrophotometric (UV) methods. The proposed method was subjected to validation tests. Results: Recovery of metformin HCl from the placebo-spiked sample was 95.1 to 96.9 % as per BP and USP methods compared with 99.3 to 100.8 % when analyzed by the proposed method. The use of methanol and ethanol as solvents resolved the problem of retention of metformin HCl by croscarmellose sodium in solution during the preparation of sample solution. Conclusion: The modified UV and HPLC methods are suitable for the determination of metformin HCl in tablets both in the presence and absence of croscarmellose sodium. The method is specific, precise, accurate, robust, rugged and gives a linear response for the quantitative estimation of metformin HCl in tablet formulation. Keywords: Tablets; Metformin HCl assay; Croscarmellose sodium; Ethanol; Methanol; HPLC, UV

Improvement of Sample Solution Preparation Method for Nitrite Determination in Foods

Improvement of Sample Solution Preparation Method for Nitrite Determination in Foods

Application of single-drop microextraction coupled with gas chromatography for the determination of multiclass pesticides in vegetables with nitrogen phosphorus and electron capture detection

In the present work the single-drop microextraction (SDME) technique coupled with GC-NPD and GC-ECD was evaluated for the determination of multi-class pesticides in vegetables. The donor sample solution preparation was optimized by testing different mixtures of solvents and dilutions with water. The SDME procedure was optimized by controlling drop organic solvent, drop volume, agitation, and exposure time. The optimum sample preparation was achieved with the use of a mixture of acetone/H 2O (10/90, v/v) in donor sample solution preparation and the consequent SDME using a toluene drop under mild stirring for 25 min. The efficiency of the extraction process was studied in fortified tomato and courgette samples and matrix effects were further estimated. The proposed method showed good linearity, limits of detection at the sub-μg kg −1 level and high precision (RSD <15%) and was applied with success in real vegetable samples showing that SDME can be a promising way for sample preparation in pesticide residue analysis.

スケトウダラ卵中の亜硝酸根定量のための試料液調製法の最適化

スケトウダラ原卵に含まれる亜硝酸根の定量では試料液の白濁やろ過遅延・発泡といった問題が生じ，これはたらこ製造の工程管理において大きな負荷要因となる．そこで，原卵とたらこの亜硝酸根分析作業の迅速化のため，前処理方法における除タンパク剤添加条件および消泡剤の使用効果について検討した．その結果，ろ過速度を速める条件として，従来法の2倍濃度の除タンパク剤を2分の1量添加する方法を見出すことができた．また，発泡抑制に有効な消泡剤はシリコン樹脂を主成分とする和光純薬のSIで，ホモジナイズ前の試料液に対し10倍希釈液を100μl添加する方法が最適であった．消泡剤添加はろ過速度の改善にも効果を示した．本法により，試料溶液のろ過速度の低下や発泡といった問題を生じるスケトウダラ卵製品の亜硝酸根量を正確に且つ迅速に測定することができる．

Development of a perfusion ion-exchange chromatography method for the separation of soybean proteins and its application to cultivar characterization

A perfusion ion-exchange chromatography method has been designed, for the first time, for the separation of soybean proteins and its application to the characterization of soybean cultivars. For that purpose, the gradient, the mobile phase composition (buffer concentration, buffer pH, and elution salt), and the temperature were optimized. The method consisted of a two-step gradient (0% B for 2 min and from 0 to 50% B in 10 min) being mobile phase A a 20 mM borate buffer (pH 9) and mobile phase B a 20 mM borate buffer (pH 9) containing 1 M sodium chloride. The procedure used for the preparation of sample solutions was significantly simpler than that proposed by other authors and basically consisted of dissolving in water. This method enabled the separation of soybean proteins from a soybean protein isolate in 11 peaks in about 9 min. The method was used to separate soybean proteins in different commercial soybeans. In general, the 11 peaks yielded by the soybean protein isolate were also observed in the chromatograms of all soybeans. However, the area percentages of every peak in every soybean enabled the differentiation between soybeans. Moreover, the method was also used to separate soybean proteins in the proteic fractions obtained from every soybean. Multivariate methods were used for patterns recognition and the classification of samples.

A novel rapid method for preparation of sample solution for chemical characterisation of titanium minerals by atomic spectrometry

A new rapid decomposition and dissolution method with a mixture of sodium di-hydrogen orthophosphate and di-sodium hydrogen orthophosphate as a novel flux is described. The minerals are fused with (1:1) mixture of the above salts (flux) and the melt is dissolved in distilled water. The solution is diluted to desired volume depending on the instrumental technique used for determination. ICP-OES is used for the determination of Al, Ca, Mg, Cr, V, Si, Fe and Ti without interference from titanium, iron and sodium phosphate (introduced as flux). All the elements except Si and V are also determined by AAS. The use of nitrous oxide–acetylene flame eliminates the depression due to titanium in the measurement of Mg, Mn, Cr and Fe in air–acetylene flame. Synthetic mixture conforming to ilmenite and rutile composition are analyzed by ICP-OES and AAS to check the validity of the method. The results are in good agreement. The proposed method has been applied to natural samples and the results are evaluated against the established decomposition method using potassium bisulphate. Both ICP-OES and AAS yielded comparable results. The R.S.D. of the proposed method in case of ICP-OES varies from 0.5 to 2%, whereas for AAS it varies from 1.5 to 3% for different elements ( n = 5). The novelty of the proposed sample decomposition lies in its simplicity, ease and speed of fusion with minimal skills besides being eco-friendly unlike the reported tedious complicated decomposition procedures involving variety of fluxes and lot of hazardous chemicals.

Silver-ion redox sensing based on colloid formation by gallate ester derivatives

Plasmon absorption of silver colloid, which was formed by reduction of silver ion with compounds bearing gallate ester groups in ethanol, was observed by absorption spectroscopy. The time-dependent absorption of silver colloid was found, which shows that the silver colloid is unstable and easy to aggregate. It seemed that a calixarene derivative bearing two gallate ester groups was the most suitable for determining silver ion. In order to prevent the silver colloid aggregation, poly( N-vinylpyrrolidone) (PVP) was added into the solution at a constant time after the preparation of sample solutions. In the calibration graph, the absorbance increased with increasing silver ion concentration, especially in the concentration range of 2.00 × 10 −6 to 1.00 × 10 −5 M. It is possible to determine silver ion concentrations using this method.

A structure-based strategy for discovery of small ligands binding to functionally unknown proteins: Combination ofin silico screening and surface plasmon resonance measurements

In the postgenomic era, many researchers and organizations have been engaged in structural and functional analyses of proteins. As a part of these efforts, searching for small organic compounds that bind specifically to target proteins is quite important. In this study, we have developed a rational strategy for ligand discovery based on the three-dimensional structures of target proteins, which were elucidated by X-ray crystallography and nuclear magnetic resonance spectroscopy. The strategy has three features: (i) rapid selection of candidate compounds by in silico screening, (ii) automated preparation of sample solutions with robotics, and (iii) reliable evaluation of the candidates with surface plasmon resonance. Applying the strategy to a protein, At2g24940 from Arabidopsis thaliana, we discovered four small ligands out of a commercially available library of about 150 000 compounds. Although these compounds had only weak affinities to the target protein, with dissociation constants ranging from 68 to 120 microM, they apparently possess common structural features. They would be leads for the development of specific inhibitors/drugs for At2g24940, and provide important clues toward elucidation of the protein function.

Determination of dopants in ZnO‐based ceramic varistors by x‐ray fluorescence and inductively coupled plasma spectrometry

AbstractA method is proposed for the x‐ray fluorescence (XRF) analysis of dopant concentrations in ZnO ceramic materials. The accuracy of the results is good for all the dopants analyzed except Bi2O3. The thermal behavior of this component was followed by thermogravimetry, showing that in an anhydrous Li2B4O7 medium, partial Bi2O3 volatilization occurs at the temperatures needed for glass bead formation (1100–1200 °C). For comparison, inductively coupled plasma atomic emission spectrometry (ICP‐AES) analysis of the materials was carried out following a wet procedure for sample solution preparation. The results were in agreement with those obtained by XRF except for Bi2O3. However, if Bi2O3 volatilization is avoided, the analysis is accurate. Copyright © 2001 John Wiley &amp; Sons, Ltd.

Liquid Chromatographic Determination of Thalidomide in Tablets, Capsules, and Raw Materials

A simple, isocratic liquid chromatographic method for assay of thalidomide in tablets, capsules, and raw materials was developed. The method uses a Nova-Pak octadecylsilane bonded-phase column (150 x 3.9 mm, 4 microns particle size), a mobile phase of acetonitrile-water (15 + 85), a flow rate of 1 mL/min, detection at 237 nm, and phenacetin as internal standard. Phosphoric acid was used in preparation of sample solutions to inhibit thalidomide hydrolysis. Assays ranged from 99.3 to 100.4% in raw materials from 4 manufacturers, from 79.7 to 104.8% in tablets from 7 manufacturers, and from 75.3 to 102.6% in capsules from 4 manufacturers. Assay method precisions for triplicate analyses on 5 days were 0.30% for tablets, 0.22% for capsules, and 0.22% for raw materials. Recovery from simulated tablet formulations was 100%. The method has been used to analyze individual tablets and capsules for determination of content uniformity.