Reductive amination of glutaraldehyde 2,4-dinitrophenylhydrazone using 2-picoline borane and high-performance liquid chromatographic analysis

• Published in: Analyst (London) Vol. 137; no. 18; pp. 4274 - 4279
• Main Authors: Uchiyama, Shigehisa, Sakamoto, Hironari, Ohno, Akiko, Inaba, Yohei, Nakagome, Hideki, Kunugita, Naoki
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 21.09.2012
• Subjects: Amination; Analytical chemistry; Chemistry; Chromatographic methods and physical methods associated with chromatography; Chromatography, High Pressure Liquid; Exact sciences and technology; Glutaral - analysis; Glutaral - chemistry; Hydrazones - chemistry; Other chromatographic methods; Spectrometric and optical methods; HPLC chromatography; Product; Identification; Single bond; NMR spectrometry; Glutaral; Organic hydrazine; Reduction; Absorption; Amination; Phosphoric acid; High performance; Borane; Gradient; Catalytic reaction; Coupled method; Solubility; Error; Absorption coefficient; Aldehyde; Wavelength; Double bond; Absorption spectrometry; Acetonitrile; Geometrical isomer; Room temperature
• ISSN: 0003-2654; 1364-5528; 1364-5528
• DOI: 10.1039/c2an35230c

A typical method for the measurement of glutaraldehyde (GLA) employs 2,4-dinitrophenylhydrazine (DNPH) to form GLA-DNPhydrazone derivatives. However, this method is subject to analytical errors because GLA-DNPhydrazone is a quaternary bis-derivative and forms three geometric isomers ( E - E , E - Z and Z - Z ) as a result of the two C&z.dbd;N double bonds. To overcome this issue, a method for transforming the C&z.dbd;N double bond into a C-N single bond, using reductive amination of DNPhydrazone derivatives, has been applied. The amination reaction of GLA-DNPhydrazones with 2-picoline borane is accelerated with catalytic amounts of acid and is completed within 10 minutes in the presence of 100 mmol L 1 phosphoric acid. Reduction of GLA-DNPhydrazone by 2-picoline borane is unique and results in the formation of N -(2,4-dinitrophenyl)-1-piperidinamine (DNPPA). NMR and LC-APCI-MS data confirmed the product identification. DNPPA is very stable and did not change when stored for at least four weeks at room temperature. DNPPA has excellent solubility of 14.6 g L 1 at 20 °C in acetonitrile. The absorption maximum wavelength and the molar absorptivity of DNPPA were 351 nm and 4.2 × 10 4 L mol 1 cm 1 respectively. Complete separation between the reduced forms of C1-C10 aldehyde DNPhydrazones, including DNPPA, can be achieved by operating the reversed-phase high-performance liquid chromatograph at 351 nm in gradient mode using a C18 amide column. The reductive amination method for GLA overcomes analytical errors caused by E - E , E - Z and Z - Z geometrical isomers. We developed a new analytical method of glutaraldehyde (GLA) using derivatization with 2,4-dinitrophenylhydrazine followed by reductive amination with 2-picoline borane. Reduction of GLA-DNPhydrazone is unique and results in the formation of N -(2,4-dinitrophenyl)-1-piperidinamine.