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1

Determination of Cd, Pb and Zn in polymers by laser ablation microwave induced plasma optical emission spectrometry

Ślachciński Mariusz, Janeda Michał, Matusiewicz Henryk

Ecological Chemistry and Engineering. S

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2023

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Vol. 30, nr 3

405--416

EN

The potential of laser ablation microwave induced plasma optical emission spectrometry (LA-MIP OES) for the analysis of plastic materials has been investigated. Inorganic species, e.g., metals may be added to them as additives, anti-oxidising agents, stabilisers, plasticisers, colorants and catalytic residues, contaminants and may be present in a wide range of concentrations. The study revealed elevated content of trace elements (Cd, Pb and Zn) which are components of poly(vinyl chloride) (PVC) and polyethylene (PE). Laser ablation using wavelengths of 266 nm as a sampling method for MIP OES was used. The result achieved using elaborated system were compared with those obtained after polymer samples decomposition in high pressure-temperature focused microwave heating digestion system and standard sample pneumatic nebulisation (PN) to MIP OES spectrometer. The calibration strategy using cellulose pellets as support for qualitative analysis for element determination in polymers by LA-MIP OES was proposed. This analytical performance of the LA-MIP OES system was characterised by a determination of the limits of detection (LODs) and precision (RSDs) for elements tested. The experimental concentration detection limits for simultaneous determination, calculated as the concentration giving a signal equal to three times of the standard deviation of the blank (LOD, 3σblank criterion, peak height) were 2 μg g–1, 3 μg g–1 and 5 μg g–1 for Cd, Pb and Zn, respectively. The method offers relatively good precision (RSD ranged from 3 % to 5 %) for micro sampling analysis.

2

Separation and quantification of nine bioactive compounds in traditional Unani formulations by High Performance Liquid Chromatography–Photodiode Array Detector

Kamal Y. T., Ahmad Sayeed, Mahadevan Nanjaian, Alam Prawez, Salam Shahana, Asiri Yahya, Muhsinah Abdullatif Bin, Alsayari Abdulrhman

Acta Chromatographica

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2021

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Vol. 33, no. 1

3--10

EN

A new High Performance Liquid Chromatography–Photodiode Array Detector (HPLC–PDA) method has been developed for the chromatographic separation and simultaneous quantitative determination of nine bioactive compounds, i.e. four phenolic (gallic acid, ellagic acid, chebulinic acid, and tannic acid), two flavanoids (rutin and quercetin), two anthraquinones (sennoside A and B) and one oxygenated hydrocarbon (vitamin C) in a well-known Unani polyherbal formulation namely Itrifal’s. Separation was accomplished on a C18 LiChrospher 100 column (5 mm, 250 3 4.6 mm) with a gradient elution and recorded at 254 nm. The results demonstrated that the proposed method is reproducible, accurate, economic, and suitable for the quality control of traditional polyherbal Unani formulations containing complex compounds with different structures such as Itrifals.

3

A reliable HPLC-DAD method for simultaneous determination of related substances in TBI-166 active pharmaceutical ingredient

Zhang Tingting, Yin Wanting, Jin Bo, Li Tong, Ma Chen

Acta Chromatographica

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2020

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Vol. 32, no. 2

80--85

EN

A sensitive, stability-indicating reversed-phase high-performance liquid chromatography with diode array detection (HPLC–DAD) method has been developed for the determination of TBI-166 and its 10 kinds of related impurities. Chromatographic separation was achieved on a Kromasil ODS column (250 mm × 4.6 mm, 5 μm), with a gradient elution of the mobile phase system consisting of acetonitrile and 1% ammonium formate solution (with 0.2% formic acid). The flow rate was 1.0 mL/min, and the detection wavelength was set at 251 nm. The method was validated according to the International Conference on Harmonization (ICH) guidelines with respect to selectivity, linearity, limits, accuracy, precision, and robustness. The calibration curves were linear from LOQ to 150% of the specification limit of impurity with correlation coefficients not less than 0.999. The limits of quantitation were between 0.123 and 0.257 μg/mL. Accuracy for the related substances was estimated by the recovery ranged from 94.6% to 111.2%. The method was proved to be reliable for the determination of related substances in TBI-166 bulk drug, which is essential and important in the quality control.

4

A comparison of ETV and LA for the determination of trace elements in solid samples by MIP OES

Matusiewicz Henryk, Ślachciński Mariusz

Ecological Chemistry and Engineering. S

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2019

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Vol. 26, nr 3

429--441

EN

The performance of electrothermal vaporization (ETV) and laser ablation (LA) of dry aerosols as sample introduction systems for microwave induced plasma optical emission spectrometry (MIP OES) are compared and evaluated in terms of detection limits, precision and accuracy for the determination of trace elements (Ca, Cd, Cu, Fe, Mg, Mn, Sr, Zn) in the same solid micro samples. In MIP OES both radiation sources can be independently adjusted to optimize the sampling process and then its subsequent excitation. A univariate approach and simplex optimization procedure were used to obtain the best signal/noise (S/N) ratio and derive analytical figures of merit. A comparison using a Student’s t-test between the results obtained by both ETV/LA-MIP OES methods for trace elements, and concentrations in standard reference material (SRM) and certified reference materials (CRMs) showed that there was no significant differences on a 95 % confidence level. The detection limits of the tested elements in solid samples by ETV/LA-MIP OES were in the range of 0.1 to 11 µg g−1 for all elements determined, while the corresponding absolute values in the range of ng. The precision of the results for ETV-MIP OES and LA-MIP OES varied between 2 and 4 % and 3 and 7 %, respectively. The linear dynamic ranges in the ETV/LA-MIP OES are extend over three decades of concentration. The methods were validated by the analysis of NIST SRM 2711Montana Soil, NRCC CRM PACS-2 Marine Sediment and NRCC CRM TORT-2 Lobster Hepatopancreas of different matrix composition and by the standard addition technique.

5

Development and validation of stability-indicating RP-HPLC method for the simultaneous determination of tizanidine HCL and meloxicam in rabbit's plasma

Zaman Muhammad, Hanif Muhammad, Khan Najm Ul Hassan, Mahmood Asif, Qaisar Muhammad Naeem, Ali Huma

Acta Chromatographica

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2019

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Vol. 31, no. 3

173--178

EN

High-performance liquid chromatography (HPLC) is a widely used technique for the simultaneous detection and quantification of different drugs. The purpose of the current study was to develop a simple and cost-effective reversed-phase high-performance liquid chromatography (RP-HPLC) method for the simultaneous determination of tizanidine (TZN) HCl and meloxicam (MLX) in rabbit's plasma. Assay of TZN and MLX was performed after extraction of drug from plasma by liquid–liquid extraction technique using methanol and diethyl ether as protein precipitants. Isocratic elution was performed in a Kromasil® C18 column (dimension, 250 × 4.60 mm; particle size, 5 μm) with mobile phase consisting of methanol–water (8:2). Orthophosphoric acid was used to adjust the pH of the mobile phase 3.0, and detection was done at 228 nm. Flow rate was 0.8 mL/min with ambient temperature and average operating pressure of 1400 psig. Retention time of TZN was 2.612 min and that of MLX was 6.960 min with a resolution of 3.18. Both drugs showed satisfactory linearity in the range of 10 to 50 ng/mL with correlation coefficients (R2) of 0.9989 and 0.9972 for TZN and MLX, respectively. The developed method was validated successfully for linearity, system suitability, intra-day and inter-day accuracy, and precision, robustness, and specificity following International Conference on Harmonization (ICH) guidelines. Conclusively, a precise, stable, reproducible, economical, and suitable method for estimation of pharmacokinetic evaluation was developed and validated.

6

A simple stability-indicating HPLC method for simultaneous analysis of paracetamol and caffeine and its application to determinations in fixed-dose combination tablet dosage form

Aminu Nafiu, Chan Siok-Yee, Khan Nasir Hayat, Farhan Ahmed Bassam, Umar Muhammad Nura, Toh Seok-Ming

Acta Chromatographica

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2019

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Vol. 31, no. 2

85--91

EN

A simple, economic, rapid, reliable, and stability-indicating high-performance liquid chromatography (HPLC) method has been developed and validated for the simultaneous determination of paracetamol (PCM) and caffeine (CF) in solid dosage form. The chromatographic separations were achieved with a Waters Symmetry® C18 column (5 μm, 4.6 × 150 mm), using a mixture of methanol and water (40:60, v/v) as a mobile phase, under isocratic elution mode with a flow rate of 0.8 mL/min, and ultraviolet (UV) detection was set at 264 nm. The oven temperature for the column was set and maintained at 35 °C. The method was validated according to International Conference on Harmonization (ICH) guidelines, and it demonstrated excellent linearity, with a correlation coefficient of 1 and 0.9999 for PCM and CF, respectively, over the concentration ranges of 15–300 μg/mL (PCM) and 2.5–50 μg/mL (CF). The retention time (tR) was found to be 2.6 ± 0.001 and 3.5 ± 0.002 min for PCM and CF, respectively. Extensive stress degradation studies were conducted by subjecting the analytes to various stress conditions of acidic and alkaline hydrolysis as well as oxidative, photolytic, and heat degradations. The method was found to efficiently separate the analytes' peaks from that of the degradation products, without any variation in their retention times. The relative standard deviation (RSD) values of all recoveries for PCM and CF were less than 1.3%. The method was found to be suitable for routine analysis of PCM and CF in pharmaceutical dosage form.

7

A simple HPLC method for the determination of butorphanol tartrate and ondansetron hydrochloride in patient-controlled analgesia solution

Fang B., Wang L., Chen F., Li P., Shi X.

Acta Chromatographica

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2018

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Vol. 30, no. 1

43--46

EN

A simple and rapid high-performance liquid chromatographic (HPLC) method was established for simultaneous determination of butorphanol tartrate and ondansetron hydrochloride in analgesic mixture samples used for patient-controlled analgesia (PCA). The separation of butorphanol tartrate and ondansetron hydrochloride in PCA solution was carried out on phenomenex C18 column (4.6 mm × 150 mm, 5 μm) using 50 mM sodium acetate (pH 4.0) buffer and acetonitrile (72:28, v/v). Flow rate was 1.0 mL min−1 with a column temperature of 30 °C, and detection wavelength was carried out at 280 nm and 306 nm. Validation of the method was made in terms of specificity, linearity, accuracy, and intra- and inter-day precision, as well as quantification and detection limits. The developed method was successfully used to evaluate the chemical stability of butorphanol tartrate and ondansetron hydrochloride in analgesic mixtures at the usual concentration used for PCA.

8

High-performance liquid chromatography fingerprints and simultaneous quantification of bioactive compounds in Salvia przewalskii Maxim

Wang L., Jiang Y. Y., Zhang L., Yang R. W., Ding C. B., Wang X. L., Zhou Y. H.

Acta Chromatographica

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2017

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Vol. 29, no. 3

291--308

EN

A high-performance liquid chromatography (HPLC) method has been developed for the simultaneous identification and quantification of active compounds (cryptotanshinone, dihydrotanshinone I, tanshinone IIA, tanshinone I, salvianolic acid A, salvianolic acid B, protocatechuic aldehyde, and rosmarinic acid) contained in traditional Chinese folk medicine Salvia przewalskii Maxim. The herb samples (including wild, cultivated, and yin pian) from fourteen main regions were investigated. Chromatographic separation was performed on an Agilent Eclipse XDB-C18 reserved-phase column (250 mm × 4.6 mm i.d., 5 μm) using gradient elution with water-formic acid (99.9: 0.1, v/v) and acetonitrile at a flow rate of 0.8 mL min-1, an operating temperature of 30 °C, and a wavelength of 275 nm. Similarity analysis (SA), principal component analysis (PCA), and hierarchical cluster analysis (HCA) were used to analyze the data based on fingerprints. For fingerprint analysis, 27 peaks were selected as the common peaks to evaluate the similarities among different samples. The results of SA showed that the method permits to obtain desired linearity, precision, accuracy, and recovery. All samples were divided into three categories by PCA and HCA, and the concentration of the eight bioactive compounds varied significantly from different regions. It was demonstrated that chromatographic fingerprinting by HPLC combined with the simultaneous determination of eight bioactive compounds was a helpful method for the quality control of S. przewalskii.

9

Development and validation of an isocratic HPLC method for simultaneous determination of quaternary mixtures of antihypertensive drugs in pharmaceutical formulations

Anderson J. F. F., Gerlin M. C. G., Sversut R. A., Oliveira L. C. S., Singh A. K., Amaral M. S., Kassab N. M.

Acta Chromatographica

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2017

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Vol. 29, no. 1

95--110

EN

The objective of this study was to develop and validate an assay method for simultaneous determination of atenolol, furosemide, losartan, and spironolactone in pharmaceutical formulations. A reverse-phase high-performance liquid chromatography procedure was developed, using a Kinetex® C-18 column (100 mm × 4.6 mm, 2.6 μm). The mobile phase was composed of metanol-water (75:25 v/v, pH 3.0, adjusted with phosphoric acid), with a flow rate of 0.4 mL min-1. All drugs were separated in less than 5 min. The method was validated according to International Conference on Harmonization (ICH) and Association of Official Analytical Chemists (AOAC) guidelines. The method showed linearity in a concentration range of 0.75–12.0 μg Ml-1 for atenolol (r = 0.9995), 0.30–12.00 μg Ml-1 for furosemide (r = 0.9997), 0.45–12.00 μg Ml-1 for losartan (r = 0.9995), and 0.45–12.0 μg Ml-1 for spironolactone (r = 0.9999). The method also showed repeatability and precision. The three-day average intra-day precisions were 101.35 ± 0.74% for atenolol, 95.84 ± 1.44% for furosemide, 98.90 ± 1.16% for losartan, and 97.19 ± 0.18% for spironolactone. Similarly, the inter-day precisions were 101.34 ± 0.72% for atenolol, 95.84 ± 0.1.50% for furosemide, 98.90 ± 1.17% for losartan, and 97.19 ± 0.83% for spironolactone. The method accuracy was also tested and validated - in this case, the average recovery values were 100.18 ± 1.20% for atenolol, 99.83 ± 1.54% for furosemide, 100.07 ± 0.95% for losartan, and 99.94 ± 0.93% for spironolactone. Finally, the method was successfully applied in the simultaneous determination of atenolol, furosemide, losartan, and spironolactone in magisterial formulas, as well as in commercial pharmaceutical formulations.

10

Development and Validation of RP-HPLC Method for Simultaneous Estimation of Glibenclamide and Thymoquinone in Rat Plasma and Its Application to Pharmacokinetics

Ahmad A., Khan R. M. A., Alkharfy K. M.

Acta Chromatographica

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2015

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Vol. 27, no. 3

435--448

EN

A rapid, accurate, and sensitive reverse phase high-performance liquid chromatographic method was developed and validated for the simultaneous determination and quantification of glibenclamide and thymoquinone in rat plasma in the presence of internal standard (thymol). Chromatograms were developed with methanol, acetonitrile, and buffer (50:20:30, v/v/v) solvent system on a Symmetry® C18 (5 μm, 3.9 × 150 mm) column, and pH was adjusted to 4.5 with orthophosphoric acid. Mobile phase was pumped at a flow rate of 1.5 mL min-1 with 254 nm ultraviolet (UV) detection. Validation of the method was performed in order to demonstrate its selectivity, linearity, precision, accuracy, limits of detection, and quantification (LOD and LOQ). Standard curves were linear (r2 = 0.996 and 0.999 for glibenclamide and thymoquinone) over the concentration range 0.5–50 μg Ml-1. The coefficient of variation (CV) of < 6% and accurate recovery of 87.54–105.19% for glibenclamide and CV of <5% and accurate recovery of 86.08–103.19% for thymoquinone were found to be in the selected concentration range of 0.5–50 μg Ml-1. The lower limits of detection and quantitation of the method were 0.109 and 0.332 μg Ml-1 for glibenclamide and 0.119 and 0.361 μg Ml-1 for thymoquinone, respectively. The within and between-day coefficients of variation were less than 7%. The validated method has been successfully applied to measure the plasma concentrations in a drug interaction study of glibenclamide with thymoquinone in an animal model to illustrate the scope and application of the method.

11

A study of impurities and degradation products in Oroxylin A by a validated liquid chromatographic method with analysis of their formation pathways

Liu W.-Y., Xie Sh.-L., Xu X. Zh., Wu Ch. Y., Feng F.

Acta Chromatographica

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2013

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Vol. 25, no. 3

451--464

EN

Oroxylin A (5,7-dihydroxy-6-methoxyflavone), which has showed multiple pharmacological effects, was semi-synthesized chemically as a pharmaceutical agent. Its impurities, degradation products and their formation pathways remain unknown. In the present study, two impurities (5,6,7-trihydroxyflavone, 5-hydroxy-6,7-dimethoxytlavone) and a degradation product (5,7-dihydroxy-8-methoxyflavone) in Oroxylin A bulk drug substance were identified, and their formation pathways were proposed. A reversed phase liquid chromatographic method for the simultaneous determination of Oroxylin A and the three compounds was developed on a C18 column using methanol-acetonitrile-0.1% acetic acid (54:23:23, v/v/v) as the mobile phase. The detection was performed at 271 nm. The method was validated to be robust, precise, specific and linear between 4 and 40 μg mL-1; the limits of detection and quantification of Oroxylin A were 0.01 and 0.04 μg mL-1, respectively. The developed method was found to be suitable to check the quality of bulk samples of Oroxylin A at the time of batch release and also during its stability studies (long term and accelerated stability).

12

Simultaneous TLC-densitometric analysis of atenolol and lercanidipine hydrochloride in tablets

Deore P. V., Shirkhedkar A. A., Surana S. J.

Acta Chromatographica

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2008

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Vol. 20, no. 3

463-473

EN

A new simple, precise, accurate, and selective thin-layer chromatographic (TLC) method has been developed for simultaneous analysis of atenolol and lercanidipine hydrochloride in a tablet dosage form. Chromatographic separation was achieved on aluminum foil plates precoated with silica gel 60F 254 , with toluene-methanoltriethylamine 3.5:1.5:0.1 (v/v) as mobile phase. Detection was performed densitometrically at 275 nm. The R F of atenolol and lercanidipine hydrochloride were 0.24 and 0.68, respectively. The reliability of the method was assessed by evaluation of linearity (2000-12000 ng per band for atenolol and 400-2400 ng per band for lercanidipine hydrochloride), accuracy (98.94 š 0.30% for atenolol and 99.75 š 0.69% for lercanidipine hydrochloride), and specificity, in accordance with ICH guidelines. The method can be used for routine simultaneous analysis of atenolol and lercanidipine hydrochloride in pharmaceutical formulations.

13

Spectrophotometric multicomponent analysis of a mixture of triprolidine hydrochloride and pseudoephedrine hydrochloride in pharmaceutical formulations by partial least-squares multivariate calibration

Donmez O. A., Bozdogan A., Kunt G., Div Y.

Chemia Analityczna

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2007

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Vol. 52, No. 1

135-140

EN

A multivariate speclropholometric calibration has been applied for simultaneous determination of triprolidine hydrochloride (TRP) and pseudoephedrine hydrochloride (PSE) in binary mixtures in tablets. Separation ofthe mixture components has been accomplished without derivatisation. For determination of the analytes, partial least-squares (PLS-2) regression analysis of spectral absorption data has been performed. Experimental calibration matrix was constructed using 9 samples, according to the full factorial design. The considered concentrations were ! 3, 15, 17 μg mL-1for TRP, and 330. 360, 390 μg mL-1 for PSE. Absorbance was measured in the range 235-315 nm, each 5 nm. The results have shown that PLS-2 is a simple and accurate method for determination of TRP and PSE in pharmaceuticals.

PL

Zastosowano wieloczynnikową, spektra fotometryczną kalibrację do równoczesnego oznaczania chlorowodorku triprolidyny (TRP) i chlorowodorku pseudoefedryny w układach dwuskładnikowych w tabletkach. Rozdzielenie mieszaniny składników przeprowadzono bez dery waty zacji. Do oznaczenia analitów zastosowano analizę regresji danych spektralnych metodą cząstkowych najmniejszych kwadratów (PLS—2). Macierz kalibracyjna skonstruowano z użyciem 9 próbek, według metody całkowitego planu czynnikowego. Rozważane stężenia wynosiły 13, 15 t 17 μg mL-1w przypadku TPR oraz 330, 360 i 390 μg mL-1 w przypadku PSE. Absorbancje mierzono w zakresie 235-315 nm co 5 nm. Uzyskane rezultaty wykazały, że dzięki zastosowaniu PLS-2 otrzymuje się prostą i dokładną metodę oznaczania TRP i PSE w postaci leków.

14

Simultaneous kinetic spectrophotometric determination of isoniazid and hydrazine using H-point standard addition method

Safavi A., Abbasitabar F., Nezhad M. R. H.

Chemia Analityczna

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2007

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Vol. 52, No. 5

835-845

EN

H-point standard addition method (HPSAM) has been suggested as a simple and selective method for simultaneous determination of isoniazid and hydrazine. Reduction of Cu(II) to Cu(l) by isoniazid and hydrazine, and subsequent complex formation between the generated Cu(I) and neocuproine (Nc) provided the possibility for sensitive indirect simultaneous determination of isoniazid and its hydrolysis product - hydrazine. A difference in reduction rate of Cu(II) with isoniazid and hydrazine was the basis of this method. The proposed procedure was successfully applied to the simultaneous determination of isoniazid (1000-4000 ng mL-1) and hydrazine (150-900 ng mL-1 .

PL

Zaproponowano użycie metody dodatku wzorca z wykorzystaniem punktu H (pomiar spektrofotometryczny przy dwóch długościach fali) do jednoczesnego, prostego i selektywnego oznaczania izoniazydu i hydrazyny. Oznaczanie tych związków jest oparte na reakcji redukcji Cu(II) do Cu(I) przez izoniazyd i hydrażyne, w wyniku której powstaje kompleks między tw;orzącym się jonem Cu(I) i neokupromą. W metodzie wykorzystuje się różnicę w szybkości redukcji Cu(II) przez izoniazyd i hy drażyne. Opracowaną procedurę zastosowano z powodzeniem do jednoczesnego oznaczania izoniazudu (1000—4000 ng mL-1) i hydrazyny (150-900 ngm L-1).

15

Thermogravimetric method for simultaneous determination of potassium and ammonium involving thermal decomposition of tetraphenylborates

Adamczyk D., Cygański A.

Chemia Analityczna

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2006

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Vol. 51, No. 2

241-249

EN

A new method for simultaneous determination of ammonium and potassium involving precipitation and thermal decomposition of K[B(C6H5)4] and NH4[B(C6H5)4 has been presented. Decomposition of tetraphenylborates has been carried out using a derivato-graph and a ihermoanalyser coupled with a mass spectrometer. Gaseous products of decomposition have been identified. Determination procedure of potassium and ammonium has been developed on the basis of the results of thermal decomposition. The proposed method is very simple. It is based on the determination of the mass loss of letraphenylborate precipitate. The results of the analysis have been calculated from the calibration plot constructed for the two-component system. The method has been applied to the analysis of urine.

PL

Opracowano metodę jednoczesnego oznaczania potasu i amonu, polegającą na wytrąceniu i rozkładzie termicznym K[B(C6H5)4] i NH4[B(C6H5)4. Przeprowadzono badania rozkładu termicznego tetrafenyloboranów stosując derywatograf oraz termoanalizator sprzężony ze spektrometrem mas. Zidentyfikowano gazowe produkty rozkładu. Wynikiem badań termicznych było opracowanie metody oznaczania potasu i amonu. Opracowana metoda jest bardzo prosta i polega na oznaczeniu ubytku masy wytrąconego osadu tetrafenyloboranów. Wyniki analizy otrzymano korzystając z krzywej wzorcowej dla układu dwuskładnikowego. Metodę zastosowano do analizy moczu.

16

Voltammetric method for the simultaneous determination of rifampicin and isoniazid in pharmaceutical formulations

Wahdan T.

Chemia Analityczna

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2005

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Vol. 50, No. 2

457-464

EN

The electrochemical oxidation of rifampicin and isoniazid has been investigated by linear sweep and cyclic voltammetry in Britton-Robinson buffer solutions as supporting electrolytes at a carbon paste electrode. The oxidation showed, for rifampicin, well-defined pH-dependent quasi-reversible peaks corresponding to a mechanism involving the same number of electrons and protons, typical of hydroquinones. For the isoniazid, an irreversible peak is observed. Using linear sweep voltammetry, direct measurement of rifampicin and isoniazid in mixture has been achieved- The method has been satisfactorily applied to determine the two compounds in commercial Rimactazid® tablets and compared with the official method of the USP XXIII with good agreement between the results.

PL

Badano elektrochemiczne utlenianie ryfampicyny i izoniazydu metodą woltamperometrii cyklicznej i woltamperometrii z liniową zmianą potencjału na elektrodzie węglowej w buforze Britton-Robinsona. Dla ryfampicyny stwierdzono dobrze określoną, typową d!a hydrochmonów quasi-odwracalna i zależną od pH, krzywą utlenienia odpowiadającą przeniesieniu takiej samej ilości protonów i elektronów. Dla izoniazydu krzywa była nieodwracalna. Stosując woltamperometrię z liniową zmianą potencjału dokonano bezpośredniego pomiaru stężenia ryfampicyny i izoniazydu w mieszaninach. Metodę zastosowano do oznaczania obu składników w handlowych tabletkach Rimactazid i porównano z metodą farmakopealną (USP XXIII) uzyskując dobrą zgodność wyników.

17

The resolution of ternary mixtures of dyes by partial least-square multivariate spectrophotometric calibration and derivative spectrophotometry

Özgür M. Ü., Koyuncu Ý., Bozdoğan A.

Chemia Analityczna

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2005

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Vol. 50, No. 3

605-614

EN

Simple and fast spectrophotometric methods for the determination of the components of ternary mixtures of dyes have been proposed. For the simultaneous determination of Sunset Yellow (E110), Tartrazine (E102), and Ponceau 4R (Ł124) in granulated drinks partial least square (PLS) method was applied to the spectrophotometric data in the range 400-600 nm, at 10 nm intervals. In the procedure 27 standard mixtures of three assayed compounds at three concentration levels were used. Absorbance measurements were performed in methanolic solutions. The results were compared with those obtained using a common derivative spectrophotometric procedure (zero-crossing technique). These procedures did not require any separation steps. Statistical evaluation of the method bias was performed. It was concluded that PLS method might be competitive with derivative procedure for the separation of ternary mixtures of dyes.

PL

Zaproponowano proste i szybkie metody spcktrofotomctryczne rozróżniania bawników w trójskładnikowej mieszaninie. W celu jednoczesnego oznaczenia El l O (Sunset Yellow), E102 (Tartrazine) i E124 (Ponceau 4R) w granulowanych napojach za pomocą cząstkowej metody najmniejszych kwadratów, mierzono absorbancję co 10 nm w zakresie 400-600 nm. W metodzie tej wykorzystywano 27 wzorcowych mieszanin tych trzech barwników w metanolu, na trzech poziomach stężeń. Uzyskane wyniki porównano z wynikami zwykle stosowanej metody spektrofotometrii pochodnej. Procedury te nie wymagają rozdzielania barwników. Przeprowadzono statystyczną ocenę obciążenia i stwierdzono, że cząstkowa metoda najmniejszych kwadratów (PLS) jest konkurencyjna w stosunku do pomiarów metodą spektrofotometrii pochodnej.

18

Determination of ternary mixtures of food dyes by zero-crossing derivative spectrophotometry

Alpdoğan G., Özgür M. Ü.

Chemia Analityczna

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2005

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Vol. 50, No. 3

593-603

EN

A derivative spectrophotometric method with zero-crossing has been described for the simultaneous determination of ternary dye mixtures: Carmoisine, Tartrazine, and Beetroot Red (E-122, E-102, and E-162), and Sunset Yellow, Tartrazine, and Beetroot Red (E-110, E-102, and E-162) ) in powdered drinks. The procedure involves extraction of the dyes from a powdered drink with distilled water, filtration, appropriate dilution, recording of the first- and second derivative UV spectra, and the measurement of absorbance values at zero-crossing wavelengths. Sensitivity and reproducibility of the method were determined using the standard mixtures. The proposed method was applied to the determination of the above dyes in commercially available powdered drink. RP-HPLC has been also applied as the reference method. Statistical evaluation of the results confirmed good agreement between both methods. However, derivative spectrophotometry has the advantage of being simple, fast, inexpensive and easy to perform.

PL

Zastosowano różniczkową metodę spektrofotometryczna z techniką zero-crossing do jednoczesnego oznaczania barwników w sproszkowanych napojach w mieszaninach trójskładnikowych: E-122 (Carmoisine), E-102 (Tartrazine) i E-162 (Beetroot Red) oraz E-110 (Sunset Yellow), E-102 (Tartrazine) i E-162 (Beetroot Red). Procedura obejmuje ekstrakcję barwników wodą ze sproszkowanych napojów, filtrowanie, rozcieńczanie, zarejestrowanie pierwszej i drugiej pochodnej widm UV oraz pomiar absorbancji przy długościach fali odpowiadających zerowaniu kolejnych pochodnych. Czuiość i odtwarzalność metody wyznaczono stosując mieszaniny wzorcowe. Metodę zastosowano do oznaczania barwników w napojach dostępnych w sprzedaży. Jako metodę porównawczą zastosowano RP-HPLC. Analiza stary styczna uzyskanych wyników wskazuje na dobrą zgodność dwóch metod. Jednakże różniczkowa spektrofotometria ma przewagę, gdyż jest prosta, szybka, niedroga i fatwa do przeprowadzenia.

19

Thermogravimetric method of simultaneous determination of potassium and ammonium by the thermal decomposition of nitritocobaltates(III) of alkali metals

Adamczyk D., Cygański A.

Chemia Analityczna

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2004

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Vol. 49, No. 3

317-326

EN

The work presents a new method of simultaneous determination of ammonium and potassium, involving precipitation and thermal decomposition of K2Na[Co(NO2)6]źH2O and (NH4)2Na[Co(NO2)6]źH2O. Using a thermoanalyser coupled with a mass spectrometer, one investigated thermal decomposition of nitritocobaltates(III) in the argon atmosphere and identified the obtained gaseous products. Decomposition of ammonium-sodium nitritocobaltate( III) requires less time and is more rapid than that of the potassium-sodium compound. This fact has been utilised to develop a thermogravimetric method for the determination of potassium and ammonium. The proposed method is very simple and is based on the determination of the loss in the mass of the nitritocobaltate(III) precipitate. The analysis results are calculated from the calibration plot constructed for the two-component system. The method has been applied to the analysis of urine.

PL

Opracowano metodę jednoczesnego oznaczania amonu i potasu polegającą na wytrąceniu i rozkładzie termicznym związków K(2)Na[Co(NO(2)6]-H(2)O i (NH(4)Na[Co(NO(2)(NO(2)(6)-H(2)O). Stosując termoanalizator sprzężony ze spektrometrem masowym przeprowadzono termiczny rozkład azotynokobaltanów(III) w atmosferze argonu i zidentyfikowano gazowe produkty rozkładu. Azotyn okobaltan(I II) sodowo-amonowy rozkłada się szybciej i znacznie gwałtowniej niż związek sodowo-potasowy. Tę właściwość wykorzystano do opracowania termogra-wimetrycznej metody oznaczania jonów potasu i amonu. Metoda jest bardzo prosta i polega na oznaczeniu straty masy wytrąconego osadu azotynokobaltanów(III). Wyniki analizy oblicza się na podstawie krzywej wzorcowej układu dwuskładnikowego. Metodę zastosowano do analizy moczu.

20

Simultaneous determination of Cu, Zn and Fe in honey using partial least square regression method PLS-2

Camiña J. M., Boeris M. S., Martinez L. D., Luco J. M., Marchevsky E. J.

Chemia Analityczna

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2004

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Vol. 49, No. 5

717-727

EN

A simple new spectrophotometric method for the simultaneous determination of Cu, Fe and Zn in honey using PLS-2 multivariate calibration method has been proposed. Pr was used as an internal standard in order to evaluate the adjustment of the samples on PLS model, and the recovery of the analytes. The result obtained for honey samples was validated applying ICP-AES method. 5-Br-PADAP [2-(5-Br-2-pyridylazo)]-5-diethylaminophenol was used as the chromogenic agent. It formed coloured complexes with the elements studied at pH 9.2. The influence of the pH ionic strengh and various interferent ions were investigated. Honey was mineralised using the NO3 - HClO4 mixture. 68 standard solutions for calibration were prepared. The absorbance of standard and sample solutions was measured in the 400-650 nm wavelength range. The concentration ranges of particular elements in standards used for calibration were as follows: Cu(II) and Fe(III) 0.04n0.40 mg L-1, Zn(II) 0.04-0.44 mg L-1, and Pr(III) 0.16-1.60 mg L-1. In order to validate the reliability of the method three commercial honey samples were studied using ICP-AES. The relative error of the determination was less than 16% between PLS and ICP-AES methods in each case. The percentage recovery in the mineralisation step was about 97%.

PL

Zaproponowano nową, prostą metodę spektrofotometryczną do jednoczesnego oznaczania Cu, Zn i Fe z użyciem PLS-2 kalibracji wielu zmiennych. Pr(III) wybrano jako wewnętrzny wzorzec aby oszacować dostosowanie próbek do modelu PSL i odzysk analitów. Otrzymane resultaty walidowano pomiarami ICP-AES. 5-Br-PADAP [2-5-Br-2-pirydyl azo)]-5 -dietylo-aminofenyl zastosowano jako czynnik chromogeniczny. Tworzył on kolorowe kompleksy z badanymi pierwiastkami przy pH 9,2. Badano wpływ pH, mocy jonowej oraz wpływy różnych pierwiastków. Miód mineralizowano używając mieszniny HNC^-HCIO,,. Przyrządzono 68 roztworów wzorcowych do kalibracji. Absorbancję mierzono w zakresie 400-650 nm. Do kalibracji użyto ncstępującezakresy stężeń: Cu(II) i Fe(III) 0,04-0,4; Zn 0,04-0,44 i Pr(III) 0,16-1,60 mg L(-1). W celu zwalidowania wiarygodności metody przeprowadzono oznaczenie próbek trzech różnych miodów metodą ICP-AES. Względny btąd oznaczenia (PLS vs ICP-AES) był mniejszy od 16%. Odtwarzalność po mineralizacji wynosiła ok. 97%.