Fluorescence experiments with quinine

O'Reilly, James E.

doi:10.1021/ed052p610

Cited by 48 publications

(38 citation statements)

References 9 publications

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“…the established by the US-FDA 11 or ANVISA). 12 Sampling throughput was improved (60 samples per hour) and reagent consumption was at least 322-fold reduced in relation to previous works 15 as a consequence of the use of intermittent flow. The proposed procedure can be considered as a clean alternative for fast quinine determination in soft drinks.…”

Section: Discussionmentioning

confidence: 92%

“…The proposed procedure consumed the equivalent to 2.2 mL of concentrated sulfuric acid, which was 322-fold lower than the consumption in the batch procedure. 15 The effluent volume was 4.0 mL per determination, which was 64-fold lower than the consumption in the batch procedure. 15 Comparison of the reagent consumption with other procedures is difficult in view of the use of other reagents 13 and solvents in chromatographic separation.…”

Section: Figures Of Meritmentioning

confidence: 91%

“…15 The effluent volume was 4.0 mL per determination, which was 64-fold lower than the consumption in the batch procedure. 15 Comparison of the reagent consumption with other procedures is difficult in view of the use of other reagents 13 and solvents in chromatographic separation. 19 However the proposed procedure can be considered a green analytical method in view of the consumption of low amounts of low toxicity reagents.…”

Section: Figures Of Meritmentioning

confidence: 91%

“…Quinine concentrations found in all samples were smaller than the limit value established by FDA 11 (108 mg L -1 as quinine sulfate), but in two cases these concentrations exceeded the limit defined by ANVISA 12 (65 mg L -1 as quinine sulfate). Table 1 shows that there is no evidence of statistically significant differences between the results obtained by the SIA procedure and those ones obtained by the fluorimetric batch reference procedure 15 at the 95% confidence level, by considering a paired student's t-test (n = 8). Other profitable characteristics are the possibility of direct determination of quinine, without prior dilution, and reduction of the analyses time (ca.…”

Section: Analysis Of Samplesmentioning

confidence: 95%

“…Diverse procedures are employed for quinine determination, 13 but the intense fluorescence in acidic medium is a quinine property that is widely used for its quantification. 14,15 Fluorimetry provides low detection limits and wide linear dynamic range, but its application is restricted because the analyte must be fluorescent or a fluorescent derivate must be produced. 16 Complex matrixes can be analyzed by high performance liquid chromatography (HPLC) 17 in normal phase 18 or based on ion-pair formation, 19 considering the ionic nature of quinine.…”

Section: Introductionmentioning

confidence: 99%

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Development of a fluorimetric sequential injection analysis (SIA) methodology for determination of quinine

Infante

Masini

2011

J. Braz. Chem. Soc.

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Desenvolveu-se uma metodologia de análise por injeção sequencial (SIA) para a determinação fluorimétrica de quinino em refrigerantes. Dispersão mínima e mistura eficiente foram obtidas aspirando-se 200 mL de amostra entre duas zonas de 100 mL de reagente (0,10 mol L -1 H 2 SO 4 ) a uma vazão de 250 mL s -1 , usando uma bobina de reação de 50 cm de comprimento (0,8 mm de diâmetro interno). Resposta linear para concentrações (C) entre 0,050 e 100,0 mg L -1 foi descrita por: I = (532 ± 40) + (2,36 ± 0,04) C, com r = 0.999, onde I é intensidade relativa de fluorescência. Coeficiente de variação e limites de detecção e quantificação foram 1,9% (0,50 mg L -1 , n = 10), 2,3 e 4,5 mg L -1 , respectivamente. A frequência de amostragem foi 60 amostras por hora, consumindo 2,2 mL de H 2 SO 4 concentrado e produzindo 4 mL de resíduos por análise. Não foram observadas diferenças significativas entre os resultados obtidos pela metodologia SIA proposta e aqueles obtidos pelo procedimento em batelada.A sequential injection analysis (SIA) methodology was developed for fluorimetric determination of quinine in soft drinks. Minimum dispersion and efficient mixing were achieved by aspirating 200 mL of sample between two 100 mL reagent zones (0.10 mol L -1 H 2 SO 4 ) at flow rate of 250 mL s -1 and using a reaction coil length of 50 cm (0.8 mm internal diameter). Linear response for quinine concentrations (C) between 0.050 and 100.0 mg L -1 was described by: I = (532 ± 40) + (2.36 ± 0.04) C, with r = 0.999, where I is the relative fluorescence intensity. The coefficient of variation and limits of detection and quantification were 1.9% (0.50 mg L -1 n = 10), 2.3 and 4.5 mg L -1 , respectively. The sampling throughput was 60 analyses per hour, consuming 2.2 mL of concentrated H 2 SO 4 and producing 4 mL of wastes per analysis. No statistically significant differences were observed between the results obtained by the proposed SIA methodology and the ones obtained by the batch procedure.Keywords: sequential injection analysis, quinine, fluorimetry, dispersion, optimization IntroductionSequential injection analysis (SIA) is a robust single channel flow technique widely used to automate analytical determinations and process control. It is based on the measurement of a transient signal resulting from sequential injection of defined sample and reagent volumes in a carrier solution under controlled dispersion. 1 The sample processing conditions can be changed by software control as required by the analytical procedure. The possibility of exploiting feedback mechanisms to change sample processing conditions using a unique physical configuration make these approaches attractive to design flow procedures for process monitoring. 2,3 The characteristics of SIA enable automation of diverse operations such as sampling, chemical derivatization, dilution, standard addition and others, improving the reproducibility. Low sample and reagent consumption and small waste generation 4,5 are remarkable features of this technique, following the principles of g...

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Section: Discussionmentioning

confidence: 92%

Section: Figures Of Meritmentioning

confidence: 91%

Section: Figures Of Meritmentioning

confidence: 91%

Section: Analysis Of Samplesmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Development of a fluorimetric sequential injection analysis (SIA) methodology for determination of quinine

Infante

Masini

2011

J. Braz. Chem. Soc.

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Molecular Spectroscopy

Stuart

2012

Analytical Techniques in the Sciences

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Flow‐Through Assay of Quinine Using Solid Contact Potentiometric Sensors Based on Molecularly Imprinted Polymers

Kamel

Sayour²

2009

Electroanalysis

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Miniaturized potentiometric membrane sensors for quinine incorporated with molecular imprinted polymer (MIP) were synthesized and implemented. Planar PVC based polymeric membrane sensors containing quinine-methacrylic and/or acrylic acid-ethylene glycol methacrylate were dispensed into anisotropically etched wells on polyimide wafers. The determination of quinine was carried out in acidic solution at pH 6, where positively charged species predominated prevalently. The suggested miniaturized planner sensors exhibited marked selectivity, sensitivity, longterm stability and reproducibility. At their optimum conditions, the sensors displayed wide concentration ranges of 4.0 Â 10with slopes of about 61.3 -55.7 mV decade À1 ; respectively. Sensors exhibit detection limits of 1.2 Â 10 À6 and 8.2 Â 10 À6 mol L À1 upon the use of methacrylic and acrylic acid monomers in the imprinted polymer, respectively. Validation of the assay method according to the quality assurance standards (range, within-day repeatability, between-day variability, standard deviation, accuracy, and good performance characteristics) which could assure good reliable novel sensors for quinine estimation was justified. Application of the proposed flow-through assay method for routine determination of quinine in soft drinks was assayed and the results compared favorably with data obtained by the standard fluorimetric method.

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Fluorescence experiments with quinine

Cited by 48 publications

References 9 publications

Development of a fluorimetric sequential injection analysis (SIA) methodology for determination of quinine

Development of a fluorimetric sequential injection analysis (SIA) methodology for determination of quinine

Molecular Spectroscopy

Flow‐Through Assay of Quinine Using Solid Contact Potentiometric Sensors Based on Molecularly Imprinted Polymers

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