Derivative Ultraviolet Spectrophotometry Research Articles

Simultaneous determination and extraction of illegal dyes Sudan orange G and Sudan red 7B using ultrasonic assisted dispersive liquid–liquid microextraction based on deep eutectic solvent followed by derivative UV-VIS spectrophotometry

ABSTRACT An ultrasonic-assisted dispersive liquid–liquid microextraction based on deep eutectic solvent was utilised for simultaneous preconcentration and determination of illegal dyes Sudan orange G (SOG) and Sudan red 7B (SR7B) using second derivative ultraviolet spectrophotometry. Under optimised conditions, the limit of detection (0.014 and 0.011 μg mL−1) and linear dynamic range (0.036–0.900 and 0.030–1.000 μg mL−1) with high determination coefficient of 0.9916 and 0.9937 were obtained for SOG and SR7B, respectively. The relative standard deviations of method (n = 3) for intra- and inter-day were obtained as 3.5% and 10.5% for SOG and 5.0% and 9.0% for SR7B. The preconcentration factor for both dyes was calculated as 75 for all experiments. The applicability of the proposed method was investigated in different real samples, including in chilli powder, lipstick, river water and also in well water. A relative recovery percentage of 88–114% was obtained for these samples. Effect of interferences for the model solutions was also examined wherein satisfactory results confirm reasonable selectivity of the proposed method.

Simultaneous determination of polymetallic ions by ratio second derivative ultraviolet spectrophotometry

Zinc hydrometallurgy is the main zinc smelting process, and the wastewater after its production contains a variety of metal ions, which must be detected and strictly controlled in real time. Aiming at the problem that it is difficult to simultaneously detect multiple metal ions in zinc hydrometallurgy wastewater due to serious spectral overlap and low resolution, a ratio second derivative spectroscopy based on continuous wavelet transform is proposed for simultaneous detection of multiple metal ions. The continuous wavelet transform is found suitable for second order linear derivation to avoid distortion and noise drying. The ratio second derivative method is used to quickly screen out the characteristic wavelength of each metal ion to be detected, and establish a high-precision and low-error analysis model suitable for simultaneous detection of zinc, nickel, cobalt and copper. The linear detection ranges are 10–100 mg/L for zinc, 0.6–6.0 mg/L for nickel, 0.3–3.0 mg/L for cobalt and 0.5–5.0 mg/L for copper. The average relative deviation for zinc, nickel, cobalt and copper was 2.83%, 3.21%, 2.28% and 2.79%, respectively. The work reported here provides a new idea for ion detection of zinc smelting industrial wastewater based on ultraviolet visible spectroscopy, and lays a foundation for online detection of polymetallic ions.

Derivative Ultraviolet Spectrophotometric Studies on Ignitable Liquids

The present article describes the potential utility of derivative ultraviolet (UV) spectrophotometric technique in the discrimination of different kinds of ignitable liquids in their neat states. Derivative UV spectrophotometry is capable of differentiating these ignitable liquids as derivative spectra have more number of points for comparison than their corresponding normal zero order spectrum. Derivative spectra are relatively simple. The technique is rapid, simple, cost-effective and can be used for the screening purpose at the initial stage of investigation. Taking into account the results obtained in the present work, it is possible to suggest the use of this technique to distinguish these ignitable liquids, if recovered from arson scene or clandestine laboratories.

Development and validation of alternative methods by non-aqueous acid-base titration and derivative ultraviolet spectrophotometry for quantification of sildenafil in raw material and tablets

Sildenafil citrate (SILC) is a potent phosphodiesterase-5 inhibitor used for erectile dysfunction and pulmonary hypertension. This study shows two simple, fast and alternative analytical methods for SILC determination by non-aqueous titration and by derivative ultraviolet spectrophotometry (DUS) in active pharmaceutical ingredient and/or dosage forms. The quantitation method of SILC active pharmaceutical ingredient by non-aqueous acid-base titration was developed using methanol as solvent and 0.1 mol/L of perchloric acid in acetic acid as titrant. The endpoint was potentiometrically detected. The non-aqueous titration method shows satisfactory repeatability and intermediate precision (RSD 0.70-1.09%). The neutralization reaction occurred in the stoichiometric ratio 1:1 in methanol. The determination of SILC active pharmaceutical ingredient or dosage forms by DUS was developed in the linear range from 10 to 40 µg/mL, in 0.01 mol/L HCl, using the first order zero-peak method at λ 256 nm. The DUS method shows selectivity toward tablets excipients, appropriate linearity (R2 0.9996), trueness (recovery range 98.86-99.30%), repeatability and intermediate precision in three concentration levels (RSD 1.17-1.28%; 1.29-1.71%, respectively). Therefore, the methods developed are excellent alternatives to sophisticated instrumental methods and can be easily applied in any pharmaceutical laboratory routine due to simple and fast executions.

First-order derivative ultraviolet spectrophotometry of imipenem–cilastatin formulations

Imipenem–cilastatin is a well-established broad-spectrum intravenous antibiotic used for the treatment of life-threatening infections worldwide. The preparation has been studied by various methods but not by ultraviolet (UV) spectroscopy, although this technique remains one of the simplest, most accurate and precise validated quality control laboratory methods. The aim of this study was to validate a method for separating the intercalating peaks of the UV spectra of imipenem and cilastatin and to compare the purity and quantities of these two active ingredients in different marketed brands. No previous studies have been conducted to compare the generic product (Cilanem®) with the original (Tienam®). First-order derivative UV spectrophotometry was used to separate the intercalating peaks of imipenem and cilastatin by measuring absorbance at 243 nm and 300 nm, respectively. Cilanem® had better physical characteristics and a higher cilastatin concentration, while the brand product Tienam® contained a higher concentration of imipenem. The generic product Cilanem® is at least non-inferior to the brand product Tienam®.

Simultaneous Determination of Timolol maleate and Brimonidine tartarate in their Pharmaceutical Dosage Form

Three new simple and selective assays were developed for the analysis of binary mixture containing timolol maleate (TM) and brimonidine tartarate (BT) in the presence of benzalkonium chloride (BZ) as a preservative in eye drops. The first derivative ultraviolet spectrophotometry was used with zero-crossing measurements at 313 nm for TM and 386 nm for BT, respectively. The second method depends on the first derivative of the ratio spectra with zero-crossing measurements at 313 nm and 391 nm for TM and BT, respectively using 0.25 µg/mL BZ as a divisor. The assays were linear over the concentration ranges 5–85 µg/ mL and 2–35 µg/mL for TM and BT, respectively. The third method was based on isocratic and mobile phase saving micellar liquid chromatographic method with a Biobasic phenyl column (150 x 1.0 mm, 5 µm particle size) and micellar mobile phase composed of 0.1M SDS, 10 % of 1-propanol and 0.1 % of TEA in 0.035M ortho phosphoric acid. UV detection was adjusted at 298 nm and 250 nm for TM and BT, respectively performed at room temperature. The linearity range for TM and BT was 2–100 µg/mL and 1–50 µg/mL, respectively. The proposed methods showed high percentage recovery, good accuracy and precision.

DETERMINATION OF LAMOTRIGINE IN TABLETS USING HPTLC, HPLC, AND DERIVATIVE SPECTROPHOTOMETRY METHODS

The determination of lamotrigine in tablets using high-performance thin-layer chromatography (HPTLC), high-performance liquid chromatography (HPLC), as well as direct, first, second, and third derivative ultraviolet spectrophotometry methods are described. HPTLC method was performed using silica plates, a mobile phase composed of toluene:acetone:ammonia (3:7:0.5, v/v/v), and a densitometric detection at 312 nm. Moreover, quantification was achieved in the concentration range of 0.25–10.0 µg/spot and with good precision (RSD = 2.19%) and recovery (97.92%), using a nonlinear calibration curve by fitting to y = a + blnx. HPLC method was performed using a Luna C18 column and isocratic elution mode with a mobile phase composed of methanol: phosphate buffer (25:75, v/v) and delivered at a flow rate 1.2 mL/min. Proposed HPLC method provided good results of precision (RSD = 1.86%) and recovery (101.51%) in the concentration range of 0.25–7.5 µg/mL using linear y = a + bx regression analysis. For the UV-derivative spectrophotometry method, all derivatives and wavelengths studied proved accurate linearity, precision (RSD = 0.96–1.87%), and recovery (96.74–101.90%). Moreover, no interference was found from tablet excipients at the selected wavelength and assay procedures. The developed methods were found to be validated and showed good precision and reproducibility.

Simultaneous Determination of Prasugrel and Aspirin by Second Order and Ratio First Order Derivative Ultraviolet Spectrophotometry

Two simple, accurate, and precise UV derivative spectrophotometric methods for the simultaneous determination of Prasugrel and Aspirin in synthetic mixture form have been developed. The first method involves measurement of second order derivative spectra of Prasugrel and Aspirin. The zero crossing wavelengths 267.62 nm and 252.40 nm were selected for estimation of Prasugrel and Aspirin, respectively. In the second method, the first order derivatives of ratio spectra were calculated and used for the determination of Prasugrel and Aspirin by measuring the peak intensity at 268 nm and 290 nm, respectively. The methods were validated as per the ICH guideline Q2 (R1). Beer’s law is followed in the range of 5–45 μg/mL for Prasugrel and 25–150 μg/mL for Aspirin by second order derivative method and 6–22 μg/mL for Prasugrel and 45–165 μg/mL for Aspirin by ratio first order derivative method. The recovery studies confirmed the accuracy of the methods. Relative standard deviations for repeatability and inter- and intraday assays were less than 2%. Hence, the described derivative spectrophotometric methods are simple, accurate, precise, and excellent alternatives to sophisticated chromatographic techniques and can be potentially used for the simultaneous determination of Prasugrel and Aspirin in combined dosage form.

Research on the Detection Method of Emulsified Oil in Condensed Water

Emulsified oil is one of the main pollutants in condensed water. At present, the difficulties in demulsification of emulsified oil and dephenolization of petroleum ether are the main challenges in quantitative determination of emulsified oil in water by UV spectrophotometry. In this paper, second derivative ultraviolet spectrophotometry and demulsification with NaCl and ultrasonic were adopted to eliminate the disturbance of petroleum ether and avoid dephenolization process. Results show that the linear range of the standard oil is from 0 to 30mg/L, the recovery lies between 90.4%-101.6%, the relative errors are no more than 3%, the coefficient of variation are no more than 1.4%, and the repeatability standard deviation is only 0.1366. These results indicate that the emulsified oil detection method established has such advantages as high sensitivity, little interference, simple determination procedure, and accurate and reliable measuring result.

Simultaneous determination of moxifloxacin and cefixime by first and ratio first derivative ultraviolet spectrophotometry.

BackgroundThe new combination of moxifloxacin HCl and cefixime trihydrate is approved for the treatment of lower respiratory tract infections in adults. At initial formulation development and screening stage a fast and reliable method for the dissolution and release testing of moxifloxacin and cefixime were highly desirable. The zero order overlaid UV spectra of moxifloxacin and cefixime showed >90% overlapping. Hence, simple, accurate precise and validated two derivative spectrophotometric methods have been developed for the determination of moxifloxacin and cefixime.MethodsIn the first derivative spectrophotometric method varying concentration of moxifloxacin and cefixime were prepared and scanned in the range of 200 to 400 nm and first derivative spectra were calculated (n = 1). The zero crossing wavelengths 287 nm and 317.9 nm were selected for determination of moxifloxacin and cefixime, respectively. In the second method the first derivative of ratio spectra was calculated and used for the determination of moxifloxacin and cefixime by measuring the peak intensity at 359.3 nm and 269.6 nm respectively.ResultsCalibration graphs were established in the range of 1–16 μg /mL and 1–15 μg /mL for both the drugs by first and ratio first derivative spectroscopic methods respectively with good correlation coefficients. Average accuracy of assay of moxifloxacin and cefixime were found to be 100.68% and 98 93%, respectively. Relative standard deviations of both inter and intraday assays were less than 1.8%. Moreover, recovery of moxifloxacin and cefixime was more than 98.7% and 99.1%, respectively.ConclusionsThe described derivative spectrophotometric methods are simple, rapid, accurate, precise and excellent alternative to sophisticated chromatographic techniques. Hence, the proposed methods can be used for the quality control of the cited drugs and can be extended for routine analysis of the drugs in formulations.

Validated stability‐indicating derivative and derivative ratio methods for the determination of some drugs used to alleviate respiratory tract disorders and their degradation products

Derivative and derivative ratio methods are presented for the determination of butamirate citrate, formoterol fumarate, montelukast sodium, and sodium cromoglycate. Using the second derivative ultraviolet (UV) spectrophotometry, butamirate citrate and formoterol fumarate were determined by measuring the peak amplitude at 260.4 and 261.8 nm, respectively, without any interference of their degradation products. Butamirate citrate degradation product, 2-phenyl butyric acid, was determined by the measurement of its second derivative amplitude at 246.7 nm where butamirate citrate displays zero crossing. Formoterol fumarate degradation product, desformyl derivative, could be evaluated through the use of the first derivative at peak amplitude of 264.8 nm where interference of formoterol fumarate is negligible. In the first mode, the zero-crossing technique was applied at 305 nm for the determination of montelukast sodium in the presence of its photodegradation product, cis-isomer. The derivative of ratio spectra of montelukast sodium and its cis- isomer were used to determine both isomers using the first derivative of the ratio spectra by measuring the amplitudes of the trough at 305 nm and the peak at 308 nm, respectively. The later technique was also used for the determination of a ternary mixture of sodium cromoglycate and its two degradation products using zero-crossing method. In the derivative ratio spectra of the ternary mixture, trough depths were measured at 271.6, 302.8 and 302.2 nm, using the second, the first, and the second mode to evaluate sodium cromoglycate, degradation product (1) and degradation product (2), respectively. All the methods were applied successfully to the pharmaceutical preparation and were validated according to ICH guidelines.

Simultaneous determination of cinnarizine and nicergoline in a binary mixture using first derivative spectra, first derivative of ratio spectra and multivariate calibration techniques

Four methods are described for the simultaneous determination of cinnarizine (Cinn) and nicergoline (Nic). The first method is based on the first derivative (1D) ultraviolet spectrophotometry, with zero crossing and peak to base measurement. The first derivative amplitudes at 216.1 and 235.0 nm were selected for the assay of cinnarizine and nicergoline, respectively. The second method is based on the first derivative of the ratio-spectra (1DD) obtained by measurement of the amplitudes at 256 and 290.6 nm for cinnarizine and nicergoline, respectively. The other two chemometric methods applied were classical least squares (CLS) and inverse least squares (ILS). The calibration of these chemometric methods that involves absorbance and concentration data matrices is used for the prediction of unknown concentrations of Cinn and Nic. The numerical values were calculated by using Matlab R12 version 6.0 and Origin 5.0 software. The linear ranges are 1–40 and 1–46 μg/mL for cinnarizine and nicergoline, respectively, for all methods. The four methods were successfully applied to assaying the pharmaceutical formulations (Cinibral® tablets).

Determination of Oxazepam in Pharmaceutical Formulation by HPTLC UV-Densitometric and UV-Derivative Spectrophotometry Methods

Methods for determination of oxazepam in pharmaceutical formulation by derivative ultraviolet (UV) spectrophotometry as well as high-performance thin-layer chromatography (HPTLC) UV densitometry were described. For UV-derivative spectrophotometry, some derivatives and wavelengths may be recommended for routine quality control of the drug of interest. On the other hand, HPTLC provided good results, but only when the calibration curve was estimated using nonlinear regression analysis. The HPTLC method was developed with silica F254 plates, a mobile phase of benzene/ethanol (5:1, v/v), and densitometric detection at 204 nm receiving R f = 0.47. Developed methods were validated and found to be sufficiently precise and reproducible for established conditions.

Studies on in vitro slow-release characteristics and anticancer effect of 5-fluorouracil-loaded immunonanoparticles

OBJECTIVE To investigate slow-release features of biodegradable anticancer 5-fluorouracil-loaded immunonanoparticles (5-FU INPs), and to assess their tumor cell killing activity in vitro. METHODS The method of vibrating dialysis at a constant temperature, and first-order derivative ultraviolet spectrophotometry were used to deter -mine the drug releasing character of 5-FU INPs. The methyl thiazolyl tetrazolium (MTT) colorimetric method was employed to assay the killing activity of 5-FU INPs on 5 tumor cell lines at different phases. RESULTS The 5-FU INPs had a favorable slow-release function, with a t1/2 release time of 10.4 days. The 5-FU INPs had a rather strong lethal effect on 5 tumor cell lines resulting in a positive correlativity between the killing activity and the action time and amount of the drug released. CONCLUSION The drug disposition is uniform from the 5-FU INPs, and there is no impact on efficacy of the 5-FU during preparation and degra -dation of the 5-FU INPs. The 5-FU INPs have a favorable function for drug release, and can maintain an effective killing activity over a long period of time.

Derivative ultraviolet spectrophotometric determination of dexchlorpheniramine maleate in tablets in presence of coloring agents

Formulation excipients can frequently affect the drug analysis in pharmaceuticals yielding background interference by ultraviolet spectrophotometry. Sample separation procedures to diminish such interferences are usually recommended as sample pre-treatment, however it can be difficult to eliminate them and they can still persist. In addition, these procedures can be time consuming and laborious to perform. Excipients, like dyeing agents can also be present in a formulation and yield color to drug solution. This work reports the successful development of a derivative ultraviolet spectrophotometry for dexchlorpheniramine maleate (DPM) determination in solid dosage forms, in spite of the color imparted to tablets solution. Standard curves obtained by second order derivative ultraviolet spectrophotometry showed linearity with a correlation coefficient of 0.9999 in the concentration range of 9.75–32.5 μg ml −1 DPM in 0.1 mol l −1 sulfuric acid, using zero-peak (ZP) and peak–peak (PP) methods. The average relative standard deviation range was between 0.26% and 1.08% and 0.18% and 0.63% for ZP and PP methods, respectively. Application of the method in tablet samples resulted in coefficients of variation in the range of 0.83–1.40%, and 0.63–0.83% for ZP and PP methods, respectively. Recovery test percentage values obtained were between 96.95% and 105.61% for the tested tablet samples.

Saccharin analysis in pharmaceutical and cosmetic preparations by derivative ultraviolet spectrophotometry

Saccharin, a synthetic sweetener constituent of several pharmaceutical and cosmetic preparations, is analyzed qualitatively and quantitatively in the presence of interferences like active ingredients and excipients. A derivative ultraviolet spectrophotometric method employing the second and the fourth orders was used. The calibration data obtained were satisfactory, with a relative precision range of 0.53%-0.72%, and linearity between 0.9998-0.9999. The recovery test results for the toothgel sample ranged between 97.80% and 104.95% in the second order of derivative and between 98.04% and 101.32% in the fourth derivative, respectively, using zero-peak (ZP) and peak-peak (PP) methods. The suspension sample showed values between 97.35% and 104.72% in the second derivative and between 95.94% to 104.41% in the fourth derivative, respectively, employing the zero-peak (ZP) and peak-peak (PP) methods. The proposed method showed precision, accuracy and simplicity.

Application of TLC-densitometry, first-derivative UV-spectrophotometry and ratio derivative spectrophotometry for the determination of dorzolamide hydrochloride and timolol maleate

Three methods are described for the simultaneous determination of dorzolamide hydrochloride (DORZ) and timolol maleate (TIM) in ophthalmic solutions. The first method is based on application of thin layer chromatographic separation of both drugs followed by the densitometric measurements of their spot areas. After separation on silica gel GF 254 plates, using methanol–ammonia 25% (100:1.5 v/v) as the mobile phase, the chromatographic zones corresponding to the spots were scanned at 253 and 297 nm, respectively. The calibration function was established in the ranges of 2–18 μg for DORZ and 0.5–4.5 μg for TIM. The second method depends on first derivative ultraviolet spectrophotometry, with zero-crossing measurement method. The first derivative values D 1 at 250.2 and 312.5 nm were selected for the assay of DORZ and TIM, respectively. Calibration graphs follow Beer's law in the range 10–64 and 2.5–16 μg ml −1, respectively. The third method is based on ratio first derivative spectrophotometry. The signals in the first derivative of the ratio spectra at 244 and 306.2 nm were selected to determine DORZ and TIM in the mixture and calibration graphs are linear in the range of 5–40 and 5.0–17.5 μg ml −1, respectively. The proposed methods were successfully applied to the determination of these compounds in synthetic mixtures and in pharmaceutical preparations. The proposed methods are simple, rapid and suitable for quality control application.

Spectrophotometric and HPTLC-densitometric determination of lisinopril and hydrochlorothiazide in binary mixtures.

Different spectrophotometric and HPTLC-densitometric methods are presented for the simultaneous determination of lisinopril and hydrochlorothiazide in pharmaceutical tablets. The spectrophotometric methods include third derivative (3D) ultraviolet spectrophotometry with zero crossing measurement at 217.4 and 233.4 nm, second derivative of the ratio spectra with measurement at 214.3 and 228.0 nm; both classical least squares and principal component regression were applied to the UV absorption and first derivative spectra of the mixture. The HPTLC method was based on separation of both drugs followed by densitometric measurements of their spots at 210 and 275 nm for lisinopril and hydrochlorothiazide, respectively. The separation was carried out on Merck HPTLC aluminum plates of silica gel 60 F254, using chloroform-ethylacetate-acetic acid (10:3:2 by vol.) as mobile phase. The linear and second order polynomial were used for the regression equation of lisinopril and hydrochlorothiazide, respectively.

Spectrophotometric determination of benazepril hydrochloride and hydrochlorothiazide in binary mixture using second derivative, second derivative of the ratio spectra and chemometric methods.

Different spectrophotometric methods are presented for the simultaneous determination of benazepril hydrochloride and hydrochlorothiazide in pharmaceutical tablets. The first method depends on second derivative (2D) ultraviolet spectrophotometry, with zero crossing and peak to base measurement. The second derivative amplitudes at 214.8 and 227.4 nm were selected for the assay of benazepril hydrochloride and hydrochlorothiazide, respectively. The second method depends on second derivative of the ratio spectra by measurement of the amplitudes at 241.2 and 273.2 nm for benazepril hydrochloride and hydrochlorothiazide, respectively. Chemometric methods, classical least squares and principal component regression, were applied to analyze the mixture. Both the chemometric methods were applied to the zero and first order spectra of the mixture. The proposed methods were successfully applied for the determination of the two drugs in laboratory prepared mixtures and in commercial tablets.

UVA/UVB sunscreen determination by second-order derivative ultraviolet spectrophotometry

UVA/UVB protective agents are important constituents in many cosmetics and sunscreen preparations. Analytical methodologies which enable the determination of combined substances with different spectrophotometric characteristics are therefore useful and cost-effective. To this end, the following substances in a sunscreen gel were analyzed: the UVB and UVA protective substances, 2-hydroxy-4-methoxy-benzophenone-5-sulphonic acid (BZP) and 2-phenylbenzymidazole-5-sulphonic acid (PBS), respectively, were evaluated by second-order derivative ultraviolet spectrophotometry in distinct solvents and wavelengths. The method used for determination of BZP in 95% ethanol was the zero-peak (ZP) at 356.0 nm. For PBS, the solvent used was 0.1 mol l −1 triethanolamine, and the methods were the ZP at 317.5 nm and the peak-peak (PP) at 317.5–323.0 nm. Statistical results for the methods showed linearity of 0.9999 and an average precision of 1.12% (ZP) for BZP, and 0.55% (ZP) and 0.63% (PP) for PBS. The average recovery for BZP and PBS were 97.28% (ZP), 103.13% (ZP) and 103.71% (PP), respectively.