岛津的热解涂层石墨管，用了不到一两百次，进样孔周围变黑，有明显的凹陷程度，酸度1%，进样量20ul，氩气纯度5个9，进样针每次都是准确插入孔中间的，求解这到底是什么原因？有知道的吗[img=,690,920]https://ng1.17img.cn/bbsfiles/images/2020/09/202009041127511817_9729_4033146_3.png[/img][img=,690,920]https://ng1.17img.cn/bbsfiles/images/2020/09/202009041129583741_1193_4033146_3.png[/img][img=,690,920]https://ng1.17img.cn/bbsfiles/images/2020/09/202009041129593351_3734_4033146_3.png[/img]