| 有机碳/元素碳热光分析方法的数据质控和优化 |
| Data Quality Control and Optimization of Organic Carbon/Elemental Carbon Thermal-Optical Analysis Method |
| 投稿时间：2024-12-03 修订日期：2025-04-14 |
| DOI：10.19316/j.issn.1002-6002.2026.01.10 |
| 中文关键词: 有机碳/元素碳分析仪 温度校准 三峰检测 碳酸盐碳 优化 |
| 英文关键词:organic carbon/elemental carbon analyzer temperature calibration three peak detection carbonate carbon optimization |
| 基金项目:国家重点研发计划(2022YFC3703005) |
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| 中文摘要: |
| 热光分析方法是国内外普遍使用的分析大气颗粒物中碳组分的方法。以当前主流DRI 2001A型有机碳(Organic Carbon,OC)/元素碳(Elemental Carbon,EC)分析仪为例,对热光分析法使用过程中的质量控制要求进行了确认和优化,主要包括滤膜前处理、温度校准、标准物质选取、三峰检测和碳酸盐碳(Carbonate Carbon,CC)去除5个方面,并提出最优质控要求。得到的结论主要包括:(1)用于碳组分分析的空白石英纤维滤膜在马弗炉中以550 ℃烘烤3 h,即可使总碳(Total Carbon,TC)测量值低于0.5 μg/cm2。(2)在启动新仪器前以及更换热电偶后,应对仪器进行温度校准。滤膜实际温度与仪器设置温度的差值在15 ℃以下时,可使每个温度阶段的碳组分浓度的相对偏差低于30%。(3)邻苯二甲酸氢钾(KHP)和蔗糖标准溶液均可用于标定校准,二者TC测量值与标准值的相对误差范围分别为-3.0%~3.1%和-4.8%~3.0%,校准曲线斜率的相对偏差为2.9%。(4)当CH4峰面积的差值高于5 000 mV·s或相对偏差超过9%时,三峰检测结果的相对标准偏差(Relative Standard Deviation,RSD)值在5%以内逐渐增大,说明还原管活性在逐渐减弱。当三峰检测结果的RSD超过5%时,应检查气瓶压力、仪器气密性、氧化管或还原管活性等,并重新绘制校准曲线。(5)特定样品应添加0.4 mol/L HCl去除CC,否则会严重干扰OC和EC的检测浓度。加酸量可通过Ca2+浓度确定。当Ca2+浓度在30 mg/L以上时,加20 μL即可完全去除CC;当Ca2+浓度在10 mg/L以下时,不建议进行加酸处理;当Ca2+浓度在10~30 mg/L之间时,需通过预实验确定加酸量。通过开展热光分析法质控要求确认和优化,可更好地对仪器测量数据进行质量控制,提高分析结果的可靠性和可比性。 |
| 英文摘要: |
| Thermal-optical analysis is a commonly used method both domestically and internationally for analyzing carbon components in atmospheric particulate matter.Taking the current mainstream DRI 2001A organic carbon/elemental carbon analyzer as an example,this study confirmed and optimized the quality control requirements during the use of the method.It mainly includes five aspects: filter pre-treatment,temperature calibration,selection of standard materials,three-peak detection,and removal of carbonate carbon (CC),with the optimal quality control requirements proposed.The conclusions obtained mainly include : (1) Blank quartz fiber filters used for carbon analysis can be baked in a muffle furnace at 550 ℃ for 3 hours,achieve a total carbon (TC) measurement value below 0.5 μg/cm2.(2) Temperature calibration of the instrument should be performed before starting a new instrument or after replacing thermocouples.When the difference between the actual filter temperature and the instrument set temperature is below 15 ℃,the relative deviation of the carbon component concentration at each temperature stage can be kept below 30%.(3) Both potassium hydrogen phthalate (KHP) and sucrose standard solutions can be used for calibration,and the relative error ranges of TC measurement values and standard values are -3.0% to 3.1% and -4.8% to 3.0%,respectively,with a relative deviation of 2.9% in the calibration curve slopes.(4) When the difference in methane peak area exceeds 5000 mV·s or the relative deviation exceeds 9%,the relative standard deviation (RSD) value of the three-peak detection results gradually increases but remains within 5%,indicating that the activity of the reduction tube is gradually weakening.When the RSD of the three-peak detection results exceeds 5%,the gas cylinder pressure,instrument airtightness,oxidation or reduction tube activity,etc.should be checked,and the calibration curve should be redrawn.(5) Specific samples should be treated with acid (0.4 mol/L HCl) to remove CC,otherwise it seriously interferes the detection concentrations of organic carbon (OC) and elemental carbon (EC).The amount of acid added can be determined by combining Ca2+ concentration.When it is above 30 mg/L,adding 20 μL of acid can completely remove CC; When below 10 mg/L,acid treatment is not recommended; When between 10-30 mg/L,pre-experiments re needed to determine the acid addition amount.By confirming and optimizing the quality control through thermal-optical analysis method,quality control of instrument measurement data can be better achieved,and the reliability and comparability of analysis results can be improved. |
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