• Mass Spectrometry Letters
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• v.11 no.1
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• pp.10-14
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• 2020

Riboflavin is a water-soluble vitamin, which serves as a precursor to flavin mononucleotide and flavin adenine dinucleotide. This study aimed to develop a simple and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis for the quantification of riboflavin in the Beagle dog plasma. This method utilized simple protein precipitation with acetonitrile and ¹³C₄, ¹⁵N₂-riboflavin was used as an internal standard (IS). For chromatographic separation, a hydrophilic interaction liquid chromatography (HILIC) column was used with gradient elution. The mobile phase consisted of 0.1% (v/v) aqueous formic acid with 10 mM ammonium formate and acetonitrile with 0.1% (v/v) formic acid. Since riboflavin is an endogenous compound, 4% bovine serum albumin in phosphate buffered saline was used as a surrogate matrix to prepare the calibration curve. The quantification limit for riboflavin in the Beagle dog plasma was 5 ng/mL. The method was fully validated for its specificity, sensitivity, accuracy and precision, recovery, and stability according to the US FDA guidance. The developed LC-MS/MS method may be useful for the in vivo pharmacokinetic studies of riboflavin.

• Bulletin of the Korean Chemical Society
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• v.32 no.4
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• pp.1158-1164
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• 2011

5-Methoxy-N,N-diisopropyltryptamine (5-MeO-DIPT), a psychoactive tryptamine derivative, is a hallucinogenic drug of abuse. In this study, 5-OH-DIPT and its metabolites were identified and the quantitative method was developed and validated by using hydrophilic interaction chromatography-tandem mass spectrometry (HILICMS/MS). Chromatographic separation was achieved on an Atlantis HILIC silica column ($5{\mu}m$, $100{\times}2.1\;mm$). The metabolites of 5-MeO-DIPT in rat urine were characterized via Q1 scanning and product ion scanning. As a consequence, 5-MeO-IPT, 5-OH-DIPT, 6-OH-5-MeO-DIPT and their glucuronide conjugates were detected and identified as the metabolites of 5-MeO-DIPT. Subsequently, a quantitative method for 5-MeO-DIPT and its major metabolites, 5-MeO-IPT and 5-OH-DIPT, was developed in multiple reactions monitoring (MRM) mode. The calibration curves for all analytes evidenced good linearity over the concentration range of 1-1000 ng/mL with linear correlation co-efficients ($r^2$) in excess of 0.99. The intra- and inter-day accuracy and precision were 92.2-110.2% and 1.5-9.9%, respectively.

• Mass Spectrometry Letters
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• v.7 no.1
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• pp.12-15
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• 2016

Results of free and bound myo-inositol in infant formula (IF) are presented. Inositol was analyzed by HILIC ultra-performance liquid chromatography coupled with mass spectrometer. The levels of free myo-inositol in 27 Australian and 4 EU originated IF samples were 300-600 mg/kg of powder or 1.6-3.1 mg/100 kJ. The amount of bound inositol in lipid fraction of IF was, on average, 10% of free myo-inositol.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.5
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• pp.612-617
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• 2008

Tetrodotoxin (TTX) analogues were first determined from the liver extracts of puffer fish, Takifugu niphobles, by LC/MS with Hydrophilic Interaction Liquid Chromatography (HILIC). In total, 7 TTX analogues were detected within 20 minutes as follows; 5,6,11-trideoxyTTX (34.0%, 1,029.6 nmol/g), 6,11-dideoxyTTX (29.3%, 887.6 nmol/g), TTX (22.1%, 667.8 nmol/g), 4,9-anhydro-TTX (11.2%, 339.3 nmol/g), 11-deoxyTTX＋5-deoxyTTX (2.6%, 78.6 nmol/g), and 4-epiTTX (0.8%, 23.6 nmol/g). Mouse toxicity of diluted liver extracts showed the highest toxicity at pH 3 (8.7 MU/mL) and decreased, as increasing pH, to 1.4 MU/mL at pH 10. At acidic (pH 5) and neutral conditions (pH 7), mouse toxicity of liver extracts (79 MU/mL) decreased slowly, as increasing temperature from $80^{\circ}C$ to $115^{\circ}C$, and time until 1 hour; in contrast, at the akaline condition (pH 9), the toxicity decreased rapidly to the more than half within 10 minutes. Individual toxicity of the fillet of T. niphobles were between $43.2{\sim}106.7$ MU, and $64{\sim}78%$ of its toxicity was eluted to soup when boiled with 3 volumes of water during 10 minutes.