Cholesterol analysis by derivatization technique is a time consuming, costly, and complex process while analyzing cholesterol without derivation is a simple, and quick method.Researchers analyzed cholesterol using both derivatization and non-derivatization techniques successfully. The objective of this study was to investigate the effect of derivatization in cholesterol analysis particularly on bakery goods.The retention time of non-derivatized cholesterol (11.62 min) and non-derivatized α-tocopherol standard (11.60 min) was very close in HP-5 capillary GC column andthey eluted together while injected as mixed standard. As a result, cholesterol content determined by non-derivatized technique could be overestimated due to the presence of α-tocopherol inbakery products. The peak resolution (Rs) between derivatized cholesterol and derivatized α-tocopherol standard using the appliedgradient GC condition was 3.1 which is well separated (>1.5) based on AOAC guidelines. The derivatized gas chromatographic cholesterol analysis method was verified by limit of detection (LOD; 0.03 mg/100 g), limit of quantification (LOQ; 0.08 mg/100 g), linearity (R2; 0.999),precision (repeatability: relative standard deviation (RSD) 1.5 %; reproducibility: RSD 1.9 %), and accuracy (102.1 % recovery). The verified cholesterol analysis method was subsequently applied to determine cholesterol content in selected bakery items, yielding a range of 2.76 ± 0.06 mg/100 g (chrysanthemum bread) to 114.26 ± 4.72 mg/100 g (castella).

Organic acidurias or acidemias are a group of diverse disorders caused by decreased or diminished activity of specific enzyme or transporter involved in the metabolism of amino acids, carbohydrates, fatty acids, and nucleic acids. Organic acidurias are generally inherited but may be acquired due to deficiency of certain cofactors or vitamins. As clinical symptoms are of nonspecific nature, definitive diagnosis of organic aciduria requires measurement of organic acids in urine or blood and sometimes enzyme activity in the cells. Gas chromatography-mass spectrometry (GC-MS) is a commonly used method for screening of organic acidurias.GC-MS procedure described here involves the use of urine volume that contains 1 μmole (113 μg) of creatinine. Internal standards (tropic and 2-ketocaproic acids) are added to the samples, followed by treatment with hydroxylamine to form oxime derivatives of the ketoacids. The mixture is then acidified, and organic acids are extracted in ethyl acetate. The organic extract is concentrated to dryness, and the residue is treated with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA)/trimethylchlorosilane (TMCS)/pyridine to form the trimethylsilyl (TMS) derivatives of the organic acids. The derivatized extract is then directly injected onto GC-MS for analysis.

Monoacylglycerol (MAG) and diacylglycerol (DAG) are minor components of edible fats and oils, and they relate to the quality of these foods. The AOCS official method Cd 11b-91 has been used to determine MAG and DAG contents in fats and oils. There are, however, difficulties in the determination of MAG and DAG using this analytical procedure. Therefore, we improved this method by modifying the trimethylsilyl derivatization procedure and replacing the internal standard (IS) material. In our modified method, TMS-HT (mixture of hexamethyldisilazane and trimethylchlorosilane) was used for derivatization of MAG and DAG, which was followed by liquid-liquid extraction with water and n-hexane solution containing the IS, tricaprin. Using the modified method, we demonstrated superior repeatability in comparison with that of the AOCS method by reducing procedural difficulties. The relative standard deviation of distearin peak areas was 1.8% or 2.9% in the modified method, while it was 5.6% in the AOCS method. In addition, capillary columns, such as DB-1ht and DB-5ht could be used in this method.

We developed a sensitive and selective method to simultaneously analyze 37 polycyclic aromatic hydrocarbon quinones (PAHQs) with GC-MS/MS and applied the method to the analysis of standard atmospheric particulate matter samples. PAHQs were reduced with zinc granules and dithiothreitol (DTT) and the reductants were immediately converted to their silylated derivatives in a test tube. Two trimethylsilyl (TMS) groups were introduced into PAHQs through the one-pot reductive TMS derivatization. The PAHQs were derivatized with a mixed silylation reagent (BSA+TMCS+TMSI; (3:2:3)), which is one of the combinations of TMS-derivatization reagents with the highest reactivity. The derivatives produced different fragmentation between o-PAHQs and p-PAHQs. Therefore, isomers that have the same molecular weight are difficult to separate on a column were separated by the selected reaction monitoring (SRM) mode using the characteristic fragmentations, allowing separation and detection of all PAHQ derivatives in less than 30min. The instrumental detection limit (IDL) of each PAHQ was 1.2-29fg/injection and the method quantification limit (MQL) was 0.8-78μg/kg sample. For quantification, six deuterated PAHQs were used as internal standards to achieve high analytical precision. We applied the developed method to four standard atmospheric particulate matter samples. Results showed that out of 37 PAHQs, 33 compounds were identified and quantified. Moreover, from the 33 PAHQs, 14 were detected for the first time. Similar values were observed for the concentrations of PAHQs that have been quantified in previous reports. This method has the highest practicality in monitoring PAHQs in atmosphere, combustion exhaust gas, and toxicity evaluation. Thus, the method has the potential to become a standard analytical method for such applications.