Exploratory study on chemical compounds related to pulmonary hypertension

热解吸系统（TDS）在分析化学领域中有着广泛的应用。大气压电离质谱仪（APIMS）可以检测到非常低水平的气体化合物。联合使用TDS和APIMS具有检测体内低水平代谢物的潜力。在本研究中，我们为APIMS的生物学应用开发了一种新的TDS。所开发的系统主要由质量流量控制器、气体清洁器和热解吸管组成，在热解吸管中，清洁后的气体通过放置在装有石英棉热源的较大管中的毛细管。热传感器安装在管的表面，管的周围是一个盘状加热器。载气的温度分布由一个温度调节器按给定的模式控制。在保持一定混合比的情况下，用相同的载气稀释解吸气并引入APIMS。载气的温度略低于温度调节器设定的温度，但以10℃/min的速率很好地遵循了它。接下来，我们将TDS-APIMS系统应用于溶液和血液中乳酸的测定。将1微升样品放入毛细管内，进行初步烘烤。采用APIMS的负电荷模式对乳酸离子进行质谱分析。乳酸离子在相对较低的温度下解吸，低于其沸点，并且在APIMS的电离室中容易带电。89 （CH3CHOHCOO-）在m/z处的峰值离子强度呈浓度依赖性增加，并在10-5 ~ 10-4 m范围内呈线性关系，乳酸（阴离子）的检出限为1.0 × 10-5 m。在两种电离状态下，光谱都得到了很好的再现。为高灵敏度大气压电离质谱仪的生物应用开发了一种新型的热解吸系统。TDS-APIMS系统成功地检测了低质量的游离有机化合物，如纳米升体积血液中的乳酸。少

Thermal desorption systems (TDS) are often used in the field of analytical chemistry. Atmospheric pressure ionization mass spectrometers (APIMS) can detect very low levels of gaseous compounds. The combined use of TDS and APIMS has the potential of detecting low levels of metabolites in the body. In the present study, we developed a new TDS for the biological application of APIMS. The developed system consists mainly of mass-flow controllers, gas cleaners and a thermal desorption tube in which the cleaned gases pass through capillary tubes placed within a larger tube packed with a quartz wool heat source. A heat sensor was attached to the surface of the tube, which was surrounded by a coiled heater. The temperature profiles of the carrier gas were controlled by a thermo-regulator at a given pattern. While maintaining a constant mixing ratio, the desorbed gas was diluted with the same carrier gas and introduced into the APIMS. The temperature of the carrier gases were slightly lower tha … More n the temperature setting of the thermo-regulator, but followed it well at a rate of 10 oC /min. We next applied the TDS-APIMS system to the measurement of lactate in solution and in blood. One micro liter of samples was put inside a capillary tube, which was preliminarily baked. The mass spectrum of lactate ions was analyzed using the negative charge mode of the APIMS. Lactate ions was desorbed at a comparatively low temperature, below its boiling point, and easily charged with electrons in the ionization chamber of the APIMS. The peak ion intensity at the m/z of 89 (CH3CHOHCOO-) increased in a concentration-dependent manner, and exhibited a linear relation within the ranges of 10-5 to 10-4 M. The detection limit of lactic acid (anion) was 1.0 x 10-5 M. Rat plasma was also analyzed in both positive and negative ion charges modes. In both ionization states the spectrums were well reproduced. In conclusion, a new type of thermal desorption system was developed for the biological application of an atmospheric pressure ionization mass spectrometer with high sensitivity. The TDS-APIMS system successfully detected free organic compounds with low mass numbers, such as lactic acid in nano-liter volumes of blood. Less