Factors affecting the stability of fluorescent isoindoles derived from reaction of o-phthalaldehyde and hydroxyalkylthiols with primary amines

Stobaugh, John F.; Repta, A.J.; Sternson, Larry A.; Garren, Kevin W.

doi:10.1016/0003-2697(83)90718-2

Cited by 115 publications

(61 citation statements)

References 18 publications

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“…[20] The fluorescent species formed in the reaction of OPA in presence of a thiol and amino acid has been identified as 1-substituted thio-2-substituted isoindole (Scheme 2). [21] Despite this well-known approach, the use of ketones for such purposes (e.g., odiacetylbenzene) has been testimonial, and thus a detailed mechanistic path for that reaction remains unknown. [20] Importantly, whereas aldehydes cannot discriminate between amines and their amino acid precursors, [20] diketones display a markedly different response between amines and amino acids (see below).…”

Section: Resultsmentioning

confidence: 99%

A High‐Throughput Screening Assay for Amino Acid Decarboxylase Activity

Médici¹,

Marı́a²,

Otten³

et al. 2011

Adv Synth Catal

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The development of sensitive and easy-toapply high-throughput screening methods is a common need in modern biocatalysis. With these powerful analytical tools in hands, chemists can easily assess enzyme libraries to identify either novel biocatalysts or improved mutants. Within biocatalysis, amino acid decarboxylases are gaining an increased importance, with several diverse applications ranging from the synthesis of bio-commodities to medical applications (e.g., synthesis of enzyme inhibitors at the level of l-DOPA decarboxylase). Herein, an efficient and simple analytical method for highthroughput screening of amino acid decarboxylase activity is reported. The method is valid for the discrimination of a broad range of amino acid/amine pairs such as l-tyrosine/tyramine, l-DOPA/dop-A C H T U N G T R E N N U N G amine, 5-hydroxy-l-tryptophan/serotonin, l-histidine/ histamine, l-serine/ethanolamine, l-tryptophan/tryptamine, l-glutamic acid/GABA, and l-alanine/ethyl-A C H T U N G T R E N N U N G amine. It has proven its versatility by using pure substrates, mixtures, or enzymatic reactions, both coming either from commercial enzymes or derived from cell-free (crude) extracts. The limit of detection was 13 mM for ethanolamine in the presence of 50 mM L-serine, while z' values were in the range 0.75-0.93, indicating the suitability for high-throughput screening.

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Section: Resultsmentioning

confidence: 99%

A High‐Throughput Screening Assay for Amino Acid Decarboxylase Activity

Médici¹,

Marı́a²,

Otten³

et al. 2011

Adv Synth Catal

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“…However, an excessive OPA concentration can accelerate the derivative decomposition rate (Stobaugh et al, 1983;Jacobs, Leburg, Madaj, 1986;Dorresteijn, 1996).…”

Section: Methods Developmentmentioning

confidence: 99%

Determination of apramycin in oral soluble powder by a HPLC method using pre-column derivatization with o-phthalaldehyde and UV detection

Antunes

Lourenço

Pinto

2011

Braz. J. Pharm. Sci.

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A high-performance liquid chromatographic method employing pre-column derivatization with o-phthalaldehyde (OPA) and 2-mercaptoacetic acid was developed for the determination of apramycin, an aminoglycoside antibiotic used in veterinary medicine, in the oral soluble powder form. The chromatographic separation was done by ion-pair HPLC using a C18 reversed-phase column, Synergy Hydro (150 mm x 4.6 mm x 4 μm) and mobile phase composed of 0.005 mol/L sodium octanosulfonate in a mixture of acetonitrile: water: acetic acid (45:55:2) (v/v/v) with a flow rate of 1.0 mL/min; the UV detector was operated at 332 nm. The developed method was validated according to official compendia guidelines, having demonstrated robustness, selectivity and linearity for the concentration range of 0.02 to 0.05 mg/mL, precision (with RSD < 2.0% both for intra and inter-day precision) accuracy (average recuperation of 99.33%) and detectivity (quantification and detection limits of 0.08 and 0.02 μg/mL, respectively). Three batches of commercial apramycin oral soluble powder were analyzed by both the proposed method and the official microbiological method, where all the results obtained were in the acceptable range (95% to 105% of labeled value of apramycin). Both methods were statistically compared by the t test, which yielded no significant differences (α = 0.05) thereby confirming the equivalence of the methods.Uniterms: Apramycin. HPLC. Microbiological Assay. Pre-column Derivatization. OPA.Foi desenvolvido um método por cromatografia líquida alta eficiência empregando derivatização pré-coluna com o-ftalaldeído (OPA) e ácido mercaptoacético para determinação de apramicina, um antibiótico aminoglicosídeo de uso veterinário, em pó oral solúvel. A separação cromatográfica foi feita por fase reversa com pareamento iônico utilizando-se coluna Synergy Hydro C18 (150 x 4,6 mm x 4 µm) e fase móvel composta por octanossulfonato de sódio 0,005 mol/L em mistura de acetonitrila:água:ácido acético nas proporções 45:55:2 (v/v/v), numa vazão de 1.0 mL/min; efetuou-se detecção por UV a 332 nm. O método foi validado de acordo com os compêndios oficiais e demonstrou robustez, seletividade, linearidade na faixa de 0,02 a 0,05 mg/mL, precisão (com DPR < 2,0% tanto para a precisão intra-dia quanto para a precisão inter-dia), exatidão (recuperação média de 99,33%) e detectabilidade (limite de quantificação e de detecção iguais a 0,08 e 0,02 µg/mL, respectivamente). Analisaram-se 3 lotes de apramicina pó oral solúvel pelo método proposto e pelo método microbiológico oficial e todos os resultados obtidos estavam dentro do limite de aceitação (95%-105% valor rotulado de apramicina). Ambos os métodos foram comparados estatisticamente pelo teste t, não sendo encontradas diferenças significativas entre eles para α=0,05, sendo os dois equivalentes.Unitermos: Apramicina. CLAE. Doseamento Microbiológico. Derivatização pré-coluna. OPA.

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“…This is presumably a result of secondary reactions between the reagents and the derivative and intramolecular reactions causing breakdown of the isoindole product Numerous authors have discussed these effects in the formation of OPA-thiol-amine isoindoles (Nakamura et al, 1982;Stobaugh et al, 1983;Allison et al, 1984;Jacobs et al, 1986) and the major loss is attributed to the reaction of excess OPA with the isoindole. "IRe stability of iso-…”

Section: Derivatization Chemistrymentioning

confidence: 99%

Low-level atmospheric sulfur dioxide measurement using HPLC/fluorescence detection

1993

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Abstract. An automated technique for measuring SO2 in ambient air has been developed. Air is passed through a gas/liquid exchange coil with an aqueous absorber solution containing 10 ~tM formaldehyde and 0.84 mM Na:EDTA. The SOz rapidly equilibrates with bisulfite (HSO~) and sulfite (SO~-) in the aqueous solution. The aqueous S(IV) is subsequently reacted with o-phthalaldehyde in the presence of excess ethanolamine to form a fluorescent isoindole in a continuous flow stream. This derivative is then separated using reversed phase HPLC and detected via fluorescence with excitation and emission wavelengths at 330 and 380 nm, respectively. The lower limit of detection is 7 pptv (S/N = 3), with a measurement period of eight minutes per sample. The instrument response is linear over several orders of magnitude.

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Factors affecting the stability of fluorescent isoindoles derived from reaction of o-phthalaldehyde and hydroxyalkylthiols with primary amines

Cited by 115 publications

References 18 publications

A High‐Throughput Screening Assay for Amino Acid Decarboxylase Activity

A High‐Throughput Screening Assay for Amino Acid Decarboxylase Activity

Determination of apramycin in oral soluble powder by a HPLC method using pre-column derivatization with o-phthalaldehyde and UV detection

Low-level atmospheric sulfur dioxide measurement using HPLC/fluorescence detection

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