Hagen T, Korson M S, Sakamoto M, Evans J E
Department of Laboratory Medicine, Children's Hospital, Boston, MA 02115, USA.
Clin Chim Acta. 1999 May;283(1-2):77-88. doi: 10.1016/s0009-8981(99)00037-6.
A gas chromatography tandem mass spectrometry method using an ion trap GC/MS system was developed to quickly screen urine samples for 14 organic acids associated with multiple organic acidemias. The following organic acids are used as diagnostic markers: methylmalonic acid, glutaric acid, 2-ketoisocaproic acid, succinylacetone, 3-methylcrotonylglycine, tiglylglycine, isovalerylglycine, fumaric acid, butyrylglycine, propionylglycine, hexanoylglycine, adipic acid, suberic acid, and sebacic acid. 2-ketocaproic acid is used as an internal standard. The samples are prepared using a solid-phase extraction and converted to trimethylsilyl derivatives. The extraction efficiency for the 14 compounds is between 57 and 106%. A derivatized standard mixture of the 14 markers is run prior to the patient samples to determine the accurate absolute and relative retention times. The samples are then injected and the product ion spectra monitored. For data analysis, one characteristic product ion plot is extracted for each of the 14 marker compounds, and the presence of a peak with the expected retention time is determined. The areas of the product ion peaks are compared with the reference range determined from 30 normal controls. Ten samples of patients with known organic acidemias were measured. For all patients, diagnostic peaks at the expected retention times of at least five times the upper limit of the reference range were detected. The method, with its relatively fast sample preparation, short 10.0 min run time and simple data analysis, is suitable for use as a quick metabolic screen of very sick patients in whom there is concern regarding the possibility of a treatable inborn error.
开发了一种使用离子阱气相色谱-串联质谱系统的方法，用于快速筛查尿液样本中与多种有机酸血症相关的14种有机酸。以下有机酸用作诊断标志物：甲基丙二酸、戊二酸、2-酮异己酸、琥珀酰丙酮、3-甲基巴豆酰甘氨酸、惕各酰甘氨酸、异戊酰甘氨酸、富马酸、丁酰甘氨酸、丙酰甘氨酸、己酰甘氨酸、己二酸、辛二酸和癸二酸。2-酮己酸用作内标。样本采用固相萃取法制备，并转化为三甲基硅烷基衍生物。14种化合物的萃取效率在57%至106%之间。在检测患者样本之前，先运行14种标志物的衍生化标准混合物，以确定准确的绝对和相对保留时间。然后注入样本并监测产物离子谱。数据分析时，为14种标志物化合物中的每一种提取一个特征产物离子图，并确定是否存在具有预期保留时间的峰。将产物离子峰的面积与30名正常对照确定的参考范围进行比较。对10例已知有机酸血症患者的样本进行了检测。对于所有患者，在预期保留时间处均检测到诊断峰，其至少为参考范围上限的五倍。该方法样本制备相对快速，运行时间短（10.0分钟）且数据分析简单，适用于对病情严重且怀疑可能患有可治疗先天性代谢缺陷的患者进行快速代谢筛查。
