• Applied Biological Chemistry
• /
• v.35 no.2
• /
• pp.132-138
• /
• 1992

For effective determination of methylthiohydantoin amino acids(MTHs) by gas liquid chromatography in the protein sequencing, derivatization with N-methyl-N-(tert.-butyl-dimethylsilyl)trifluoroacetamide(MTBSTFA), a new silylating reagents, was attempted instead of trimethylsilyl(TMSi) derivatives by N,O-bis(trimethylsilyl)trifluoroacetamide(BSTFA) used up to the present and N(O)-butyldimethylsilyl MTHs derivatized by MTBSTFA were analysed on HP-1 capillary column. Twenty one protein amino acids except cystine were indentified. Especially arginine that did not detected with TMSi derivative on packed column until now was resolved by derivatization with MTBSTFA. N(O)-butyldimethylsilyl MTHs showed multiple peaks by MTBSTFA were proline, isoleucine, glycine and tyrosine and hydroxyproline especially showed several extraneous peaks more than two. Calibration curves of N(O)-butyldimethysilyl MTHs of amino acids in the range of $2.5\;nmol{\sim}7.5\;nmole$ showed good linearity. however, those of lysine, histidine and arginine showed linearity in the range of $5.0\;nmole{\sim}15.0\;nmole$. Correlation coefficients and regression coefficients of all calibration curves were highly significant(p<0.001).

• BMB Reports
• /
• v.41 no.1
• /
• pp.23-28
• /
• 2008

The altered amino acid (AA) levels as neurotransmitter closely correlate to neurodegenerative conditions including Alzheimer's disease (AD). Target profiling analysis of nineteen AAs in brain cortex samples from three Tg2576 mice as AD model and three littermate mice as control model was achieved as their N(O,S)-ethoxycarbonyl/tert-butyldimethylsilyl derivatives by gas chromatography. Subsequently, star pattern recognition analysis was performed on the brain AA levels of AD mice after normalization to the corresponding control median values. As compared to control mice, $\gamma$-aminobutyric acid among ten AAs found in brain samples was significantly reduced (P < 0.01) while leucine was significantly elevated (P < 0.02) in AD mice. The normalized AA levels of the three AD mice were transformed into distorted star patterns which was different from the decagonal shape of control median. The present method allowed visual discrimination of the three AD mice from the controls based on the ten normalized AA levels.

• Journal of The Korean Society of Inherited Metabolic disease
• /
• v.17 no.2
• /
• pp.39-47
• /
• 2017

Purpose: A sensitive gas chromatography mass spectrometry (GC-MS) method was developed for screening of fatty acid oxidation disorders. Methods: The assay utilized a simple protein precipitation with sulfosalicylic acid followed by tert-butyl dimethylsilyl (TBDMS) derivatization of hydroxyl functional group by N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide (MTBSTFA). Results: Calibration curves of spiked pooled plasma showed a linear relationship in the range of 0.01 ng -2 mg with correlation coefficient value greater than 0.98. Limits of detection (LOD) and limits of quantification (LOQ) were found in the range of 0.9-8.8 ng and 9-88 ng, respectively. Conclusion: The new developed method might be useful for a rapid, sensitive screening of inherited fatty acid oxidation disorders. In addition, the method expected to be one of the alternative method for screening newborns of metabolic disorders in the laboratories where expensive MS/MS is unavailable.

• Biomolecules & Therapeutics
• /
• v.15 no.4
• /
• pp.266-272
• /
• 2007

A rapid analytical method was developed to quantify very long-chain fatty acids (VLCFAs, C22:0, C24:0, C26:0) in human plasma with good sensitivity and specificity using tert-butyldimethylsilyl (TBDMS) derivatization and stable isotope GC-MS selective ion monitoring (GC-MS/SIM). Two-hundred and fifty ${\mu}L$ of plasma was fortified with deuterated stable isotope internal standards (d3-C22:0, d3-C24:0, d3-C26:0) and standard mixtures of chloroform and methanol, and then extracted with hexane and acetonitrile. To upper layer of liquid-liquid-extraction, N-(t-Butyldimethylsilyl)-N-methyltrifluoroacetamide was added and then heated to $60^{\circ}C$ for 30 min to produce the TBDMS derivatives. Derivatives of VLCFAs were analyzed by GC-MS/SIM. Calibration curves showed a linear relationship for the target compounds in the concentration range of $10^{-4}{\sim}2{\times}10^3\;{\mu}g/mL$ with the correlation coefficient ranging from 0.996 to 0.999. The limit of quantification for the plasma was $10^{-4}{\sim}2{\times}10^{-4}\;{\mu}g/mL$ (S/N=3). When applied to the plasma specimens of patients with peroxisomal disorder, X-linked adrenoleucodystropy (ALD, Mckusick 202370), the method clearly differentiated normal subjects from ALD patients. The C24:0/C22:0 and C26:0/C22:0 ratios were significantly elevated in the plasma of patients with X-linked ALD compared to normal subjects. The new developed method might be useful for a rapid and sensitive diagnosis of X-linked ALD and other peroxisomal disorders.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.3
• /
• pp.977-980
• /
• 2011

A new analytical method for measurement of 3,4-dihydroxyphenylalanine (DOPA) in human urine was developed. DOPA from an aqueous solution was converted into an ethoxycarbonyl (EOC) derivative. A tertbutyldimethylsilyl (TBDMS) reaction under anhydrous conditions was then attempted for analysis by gas chromatography-mass spectrometry in selected ion monitoring mode. A new mass spectral data on DOPA as a tri-EOC/mono-TBDMS derivative was built. This method showed good linearity (r ${\geq}$ 0.999), precision (% relative standard deviation = 3.1-9.2), and accuracy (% relative error = -7.2-8.8), with a detection limit of 0.05 ng/mL. This selective and accurate method of DOPA analysis will be useful for biochemical monitoring of various neurological disorders including Parkinson's disease in biological fluids.

• Archives of Pharmacal Research
• /
• v.17 no.3
• /
• pp.175-181
• /
• 1994

The solid-phase extraction (SPF) with subsequent tert-butyldimethylsilyl (TBDMS) derivatization was investigated for the rapid profiling and screening of various carboxylated non-steroidal antiinflammatory drugs (NSAIDs) simultaneously in biological fluid samples. Compared to the conventional SPF in adsorption mode using Chromosorb 102, Chromosorb 107, Carbopak B and Thermosorb, the SPF in partition mode using Chromosorb P as the adsorbent, and ethyl acetate/methylene chloride as the eluting solvents provided hightest overall recovenies of the NSAIDs from aqueous solutions with good precision. The solid-phase extracted NASIDs were silylated with N-methyl-N-(tert-butyldimethylsily)trifuoroacetamide to TBDMS derivatives and directly analyzed by capillary gas chromatography and gs chromatography-mass spectrometry. The usefulness of the present method was examined for the profilling and screening of saliva, serum and urine samples for various NSAIDs simultaneously.

• Proceedings of the Korea Society of Environmental Toocicology Conference
• /
• 2003.05a
• /
• pp.145-145
• /
• 2003

A method for the determination of alkylphenols, chlorophenols and bisphenol A in paper materials using GC/MS-SIM has been developed. Eleven endocrine disrupting chemicals (EDCs) of phenols in paper samples were extracted with acetonitrile. Also, solid-phase extraction (SPE) with XAD-4 and subsequent conversion to isobutoxycarbonyl derivatives or tert.-butyldimethylsilyl derivatives for sensitive analysis with the selected ion-monitoring (SIM) mode. The recoveries were 82.4∼108.8 % by area ratio of pheranthrene-d$\sub$10/ vs bisphenol A d$\sub$l6/. (isoBOC derivatization and TBDMS derivatization) The SIM responses were linear with the correlation coefficient varying 0.9717∼0.9995 (isoBOC derivatization), and 0.9842∼0.9980 (TBDMS derivatization). The range of concentrations was respectively, 0.95∼l.44 ng/g in 2,4-dichlorophenol, 1.01∼1.17 ng/g in t-butylphenol, 2.17∼5.84 ng/g in pentachlorophenol, 12.68∼14.88 ng/g in nonylphenol and 30.84∼153.72 ng/g in bisphenol A.

• Proceedings of the Korea Society of Environmental Toocicology Conference
• /
• 2003.10a
• /
• pp.149-149
• /
• 2003

A new technique is proposed for the determination of alkylphenols, chlorophenols and bisphenol A in tap water. The sample preparation consists of a solid phase extraction (SPE) of alkylphenols, chlorophenols and bisphenol A from a water sample with XAD-4 and subsequent conversion to isobutyloxycarbonyl (isoBOC) derivatives or tert.-butyldimethylsilyl (TBDMS) derivatives for sensitive analysis with the GC/MS-SIM mode. The recoveries were 86.6∼105.2 % (isoBOC derivatization) and 97.6∼484.5 % (TBDMS derivatization), respectively. The limit of quantitation of alkylphenols, chlorophenols and bisphenol A for SIM were 0.001∼0.050 $\mu\textrm{g}$/l (isoBOC derivatization) and 0.003∼0.050 $\mu\textrm{g}$/l (TBDMS derivatization). The SIM responses were linear with the correlation coefficient varying 0.9755∼0.9981 (isoBOC derivatization), and 0.9908∼0.9996 (TBDMS derivatization). The derivative methods and their application to tap water samples will be disscussed.

• Analytical Science and Technology
• /
• v.15 no.3
• /
• pp.196-213
• /
• 2002

The alkylphenols, chlorophenols and bisphenol A were determined by gas chromatography/mass spectrometry-selected ion monitoring mode followed by three work-up methods for comparison; EPA method, isoBOC derivatization method and TBDMS derivatization method. Eleven phenols in water samples were extracted with dichloromethane. Also, solid-phase extraction (SPE) with XAD-4 and subsequent conversion to isobutoxycarbonyl derivatives or tert.-butyldimethylsilyl derivatives for sensitive analysis with the selected ion-monitoring (SIM) mode. The recoveries were 85.1~109.9% (EPA method) and 90.3~126.6% (isoBOC derivatization and TBDMS derivatization), respectively. The method detection limit of bisphenol A for SIM were 0.732 ${\mu}g/{\ell}$ (EPA method), 0.002 ${\mu}g/{\ell}$ (isoBOC derivatization) and 0.021 ${\mu}g/{\ell}$ (TBDMS derivatization). The SIM responses were linear with the correlation coefficient varying 0.9755~0.9981 (isoBOC derivatization), and 0.9908~0.9996 (TBDMS derivatization). When these methods were applied to treated wastewater sample from a polyethylene plant, the concentrations of 11 phenols were below the method detection limit.

• Archives of Pharmacal Research
• /
• v.26 no.9
• /
• pp.697-705
• /
• 2003

The alkylphenols, chlorophenols, and bisphenol A were determined by gas chromatography/mass spectrometry-selected ion monitoring (GC/MS-SIM) followed by two work-up methods for comparison: isobutoxycarbonyl (isoBOC) derivatization and tert-butyldimethylsilyl (TBDMS) derivatization. Eleven endocrine disrupting chemicals (EDCs) of phenols in biological samples were extracted with acetonitrile and then the acetonitrile layer underwent freezing filtration 6$0^{\circ}C$ for 2 hours. Solid-phase extraction (SPE) was used with XAD-4 and subsequent conversion to isoBOC or TBDMS derivatives for sensitivity analysis with the GC/MS-SIM mode. For isoBOC derivatization and TBDMS derivatization the recoveries were 92.3∼150.6% and 93.8∼108.3%, the method detection limits (MDLs) of bisphenol A for SIM were 0.062 $\mu$ g/kg and 0.010 $\mu$ g/kg, and the SIM responses were linear with the correlation coefficient varying by 0.9755∼0.9981 and 0.9908∼0.9996, respectively. When these methods were applied to mackerel samples, the concentrations of the 11 phenol EDCs were below the MDL.