自动滴定仪测定土壤有机碳及其组分的方法优化

李朝英; 郑路; 郑之卓; 李华; 王亚南; 明安刚

doi:10.15898/j.ykcs.202404210092

自动滴定仪测定土壤有机碳及其组分的方法优化

李朝英^1,,
郑路^{1, 2, ,},
郑之卓³,
李华^{1, 2},
王亚南^{1, 2},
明安刚^{1, 2}

1.
中国林业科学研究院热带林业实验中心，广西凭祥 532600
2.
广西友谊关森林生态系统国家定位观测研究站，崇左凭祥友谊关森林生态系统广西野外科学观测研究站，广西凭祥 532600
3.
上海华东理工大学化学与分子工程学院，上海 201400

基金项目: 崇左凭祥友谊关森林生态系统广西野外科学观测研究站科研能力建设项目(桂科22-035-130-03)；广西林业科技推广示范项目(桂林科研[2022]第27号，2023GXLK45)

详细信息

作者简介:
李朝英，高级实验师，从事实验室检测分析工作。E-mail：lzying1877@sina.com

通讯作者:
郑路，高级工程师，主要研究方向为森林生态学。E-mail：zhengluli@163.com。

中图分类号: P595.2；S151.93
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出版历程
- 收稿日期: 2024-04-20
- 修回日期: 2024-07-08
- 录用日期: 2024-07-16

Method Optimization for the Determination of Soil Organic Carbon and Its Components by Automatic Titrator

LI Zhaoying^1,,
ZHENG Lu^{1, 2, ,},
ZHENG Zhizhuo³,
LI Hua^{1, 2},
WANG Yanan^{1, 2},
MING Angang^{1, 2}

1.
Experimental Center of Tropical Forestry, Chinese Academy of Forestry, Pingxiang 532600, China
2.
Guangxi Youyiguan Forest Ecosystem National observation and Research Station, Youyiguan Forest Ecosystem Observation and Research Station of Guangxi, Pingxiang 532600, China
3.
School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 201400, China

摘要

摘要:
土壤有机碳及其组分(颗粒有机碳、矿物结合态有机碳等)是反映土壤质量的关键性指标，开展准确高效地测定这些指标对相关研究具有重要意义。自动滴定仪与传统人工滴定相比，人员工作强度低，检测准确，但检测效率不及人工滴定的30%。为解决此问题，本文探讨了4种氧化剂加入量对测定有机碳的影响，研究了提前预加滴定液对检测效率提高的效果。最终优选氧化剂加入量为2mL，预加滴定液量以空白样滴定量的1/3计，建立了用于测定土壤有机碳的自动滴定仪法。采用有机碳不同水平的土壤样品和标准物质对方法进行验证，并与人工滴定进行比较，结果表明，自动滴定仪法与人工滴定法无显著性差异，方法的相对标准偏差(RSD，n=6)在2.10%～12.96%，加标回收率在93.37%～98.06%，标准物质相对误差为4.31%～4.79%；优化后的自动滴定法单个试样滴定用时由11min缩短到3.5min，整体检测效率高于人工滴定，而试剂耗用量仅是人工滴定法的40%。自动滴定仪法显著提升了有机碳的检测能力。
- 自动滴定仪 /
- 人工滴定 /
- 土壤有机碳 /
- 氧化剂加入量 /
- 预加滴定量
Abstract:
The rapid and accurate detection of soil organic carbon and its components (such as particulate organic carbon and mineral-associated organic carbon) is of great significance because they are the key indicators reflecting soil quality. Compared with manual titration, the automatic titrator has a low work intensity and accurate detection, but its detection efficiency is less than 30% of that of manual titration. To solve this problem, the influence of the addition amount of four oxidants on the determination of organic carbon was explored, and the effect of pre-adding titrant in advance on the improvement of detection efficiency was studied. Finally, the optimal addition amount of oxidant was 2mL, and the amount of the pre-added titrant was one-third of the titration amount of the blank sample. An automatic titrator method for the determination of soil organic carbon was established. This method was verified by using soil samples with different levels of organic carbon and reference substances and was compared with manual titration. The results showed that there was no significant difference between the automatic titrator and the manual titration. The relative standard deviation (RSD, n=6) of the method was 2.10%−12.96%, the recovery rate of standard addition was 93.37%−98.06%, and the relative error of the reference material was 4.31%−4.79%. The titration time of a single sample was shortened from 11min to 3.5min, and the overall detection efficiency was higher than that of manual titration. The reagent consumption was only 40% of that of manual titration. The automatic titrator significantly improved the detection ability of organic carbon.
- automatic titrator /
- manual titration /
- soil organic carbon /
- the addition amount of oxidants /
- amount of the pre-added titrant

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表 1 氧化剂不同加入量的比较(n=10)

Table 1 Comparison of different addition amounts of oxidants (n=10)

氧化剂加入量	有机碳含量(g/kg)		空白耗用硫酸亚铁量 (mL)	滴定用时 (min)	终点颜色稳定性
氧化剂加入量	显著性	含量范围	空白耗用硫酸亚铁量 (mL)	滴定用时 (min)	终点颜色稳定性
5+5	0.054	3.65～48.91	20	10	稳定
3+3		3.78～47.17	12	6	稳定
2+2		3.61～48.56	8	3.5	稳定
1+1		3.44～48.98	4	2.5	不稳定
注：显著性为有机碳含量主体间效应检验结果。

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表 2 不同称样量的可测有机碳含量比较

Table 2 Comparison of measurable organic carbon content with different sample weighing amounts

称样量 (g)	可测有机碳含量最高值 (g/kg)	称样量 (g)	可测有机碳含量最高值 (g/kg)
0.0200	176.00	0.1000	35.20
0.0400	88.00	0.2000	17.60
0.0600	58.67	0.3000	11.73
0.0800	44.00	0.4000	8.80
注：以上可测有机碳含量最高值均按空白样滴定量8.40mL、最小滴定量2.8mL进行计算。

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表 3 两种检测方法的配对样本t检验结果

Table 3 Paired sample t-test of the two detection methods

测定方法	有机碳含量测定平均值 (g/kg)	样本数量 N	标准差	成对样本相关性 (双侧p)	t	显著性 (双侧p)
自动滴定仪法	16.56	57	14.59	r=0.997	−1.780	0.081
人工滴定法	16.83	57	14.48	r=0.997	−1.780	0.081

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表 4 两种方法的精密度

Table 4 Precision of the two methods

测定方法	土壤样品编号	有机碳含量6次测定值(g/kg)						有机碳含量平均值 (g/kg)	RSD (%)
测定方法	土壤样品编号	1	2	3	4	5	6	有机碳含量平均值 (g/kg)	RSD (%)
自动滴定仪法	12	13.01	12.62	12.85	12.94	12.88	12.29	12.76±0.27	2.10
	15	8.48	8.75	8.36	8.08	9.18	8.96	8.63±0.41	4.70
	24	46.61	47.75	49.85	46.63	49.04	50.27	48.36±1.60	3.30
	52	4.96	3.66	3.58	3.86	4.25	4.50	4.13±0.54	12.96
人工滴定法	12	13.19	14.10	11.17	13.18	13.70	12.40	12.96±1.13	8.72
	15	8.50	8.58	6.79	8.81	9.67	8.79	8.52±1.05	12.29
	24	48.41	52.27	48.21	50.72	50.78	48.67	49.84±1.65	3.31
	52	3.87	3.54	3.29	4.46	4.40	3.94	3.92±0.52	13.20

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表 5 两种方法的加标回收率

Table 5 Recovery of standard addition for the two methods

测定方法	土壤样品编号	称样量 (g)	碳含量本底值 (mg)	加标量 (mg)	加标测定值(mg)			加标回收率(%)			加标回收率平均值(%)
测定方法	土壤样品编号	称样量 (g)	碳含量本底值 (mg)	加标量 (mg)	1	2	3	1	2	3	加标回收率平均值(%)
自动滴定仪法	12	0.2053	2.62	2	4.49	4.45	4.55	93.67	91.38	96.54	93.37±1.85
	12	0.2053	2.62	4	6.38	6.33	6.3	94.05	92.68	91.93	93.37±1.85
	15	0.2640	2.28	2	4.12	4.15	4.14	92.00	93.50	93.00	94.29±1.78
	15	0.2640	2.28	4	6.15	6.11	6.07	96.75	95.75	94.75	94.29±1.78
	24	0.0448	2.17	2	4.03	4.11	4.16	93.00	96.80	99.55	94.92±2.72
	24	0.0448	2.17	4	5.94	5.89	5.88	94.34	93.00	92.85	94.92±2.72
	52	0.3559	1.47	2	3.53	3.4	3.37	102.78	96.29	94.79	98.06±2.72
	52	0.3559	1.47	4	5.37	5.42	5.4	97.45	98.83	98.20	98.06±2.72
人工滴定法	12	0.2022	2.62	2	4.48	4.39	4.5	92.97	88.74	93.75	92.56±2.05
	12	0.2022	2.62	4	6.36	6.3	6.4	93.55	91.93	94.43	92.56±2.05
	15	0.2679	2.28	2	4.06	3.98	4.1	89.00	85.00	91.00	91.88±4.46
	15	0.2679	2.28	4	6.17	6.08	6.04	97.25	95.00	94.00	91.88±4.46
	24	0.0435	2.17	2	3.99	4.11	4.18	90.81	96.80	100.55	93.72±4.32
	24	0.0435	2.17	4	5.93	5.74	5.8	94.09	89.23	90.85	93.72±4.32
	52	0.3742	1.47	2	3.51	3.38	3.35	101.78	95.29	93.79	97.63±2.81
	52	0.3742	1.47	4	5.39	5.43	5.39	97.95	99.03	97.95	97.63±2.81

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表 6 自动滴定仪方法测定土壤中有机碳含量的准确度

Table 6 Accuracy for the determination of organic carbon content by the automatic titrator

标准物质编号	有机碳含量标准值 (g/kg)	有机碳含量测定结果(g/kg)				有机碳含量平均值 (g/kg)	相对误差 (%)
标准物质编号	有机碳含量标准值 (g/kg)	1	2	3	4	有机碳含量平均值 (g/kg)	相对误差 (%)
GBW07493	9.05±0.99	8.48	8.75	8.36	8.96	8.64±0.27	4.53
GBW07415	19.32±0.58	19.16	18.39	18.03	18.00	18.40±0.54	4.79
GBW07412b	27.15±1.10	28.84	28.72	27.93	27.77	28.32±0.47	4.31

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表 7 两种方法检测效率及试剂耗用量的比较

Table 7 Comparison of detection efficiency and reagent consumption with the two methods

工效参数	人工滴定法	自动滴定仪法
称样和消煮用时	10h	10h(有9h工作与滴定同步)
滴定用时	10h	18h(9h的滴定与称样和消煮同步进行)
器皿清洁用时	4h	4h(4h的清洗工作与滴定同步进行)
人工操作用时	24h	14
检测总用时	24h	19
人员工作特点	连续操作	非连续操作
人员工作强度	大	小
重铬酸钾+硫酸用量	5mL+5mL	2mL+2mL
0.2mol/L硫酸亚铁溶液用量	2400～7500mL	800～2400mL
邻菲啰啉用量	30mL	0

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参考文献(23)

[1]	武振丹, 马尚飞, 卢俊艳, 等. 贝加尔针茅草甸草原土壤有机碳组分对长期氮素添加的响应[J]. 土壤学报, 2023, 60(5): 1520−1530. doi: 10.11766/trxb202204230204 Wu Z D, Ma S F, Lu J Y, et al. Responses of soil organic carbon components to long-term nitrogen addition in the Stipa Baicalensis madow steppe[J]. Acta Pedologica Sinica, 2023, 60(5): 1520−1530. doi: 10.11766/trxb202204230204
[2]	赵元, 张伟, 胡培雷, 等. 桂西北喀斯特峰丛洼地不同植被恢复方式下土壤有机碳组分变化特征[J]. 生态学报, 2021, 41(21): 8535−8544. doi: 10.5846/stxb202101140151 Zhao Y, Zhang W, Hu P L, et al. Responses of soil organic carbon fractions to different vegetation restoration in a typical karst depression[J]. Acta Ecologica Sinica, 2021, 41(21): 8535−8544. doi: 10.5846/stxb202101140151
[3]	张方方, 岳善超, 李世清. 土壤有机碳组分化学测定方法及碳指数研究进展[J]. 农业环境科学学报, 2021, 40(2): 252−259. doi: 10.11654/jaes.2020-0886 Zhang F F, Yue S C, Li S Q. Chemical methods to determine soil organic carbon fractions and carbon indexes: A reviews[J]. Journal of Agro-Environment Science, 2021, 40(2): 252−259. doi: 10.11654/jaes.2020-0886
[4]	鲍士旦. 土壤农化分析[M]. 北京: 中国农业出版社, 2000. Bao S D. Methods of soil agricultural analysis[M]. Beijing: China Agricultural Publishing House, 2000.
[5]	李朝英, 郑路. 土壤颗粒粒径及进样量对TOC含量测定精度的影响[J]. 上海农业学报, 2018, 34(5): 8−13. doi: 10.15955/j.issn1000-3924.2018.05.02 Li Z Y, Zheng L. Effects of soil particle size and sample size on the determination accuracy of TOC content[J]. Acta Agriculturae Shanghai, 2018, 34(5): 8−13. doi: 10.15955/j.issn1000-3924.2018.05.02
[6]	陈宗定, 许春雪, 安子怡, 等. 土壤碳赋存形态及分析方法研究进展[J]. 岩矿测试, 2019, 38(2): 233−244. doi: 10.15898/j.cnki.11-2131/td.201709270148 Chen Z D, Xu C X, An Z Y, et al. Research progress on fraction and analysis methods of soil carbon[J]. Rock and Mineral Analysis, 2019, 38(2): 233−244. doi: 10.15898/j.cnki.11-2131/td.201709270148
[7]	许智超, 孙玮琳, 王晓芳, 等. 沉积岩中总有机碳测定的自动预处理方法[J]. 岩矿测试, 2023, 42(6): 1230−1239. doi: 10.15898/j.ykcs.202208240157 Xu Z C, Sun W L, Wang X F, et al. Automatic pretreatment methods for determination of total organic carbon in sedimentary rocks[J]. Rock and Mineral Analysis, 2023, 42(6): 1230−1239. doi: 10.15898/j.ykcs.202208240157
[8]	王攀磊, 秦凤琴, 蔡培, 等. 华北半湿润地区土壤酸化和有机碳测定方法的比较[J]. 土壤通报, 2014, 45(4): 863−870. doi: 10.19336/j.cnki.trtb.2014.04.016 Wang P L, Qin F Q, Cai P, et al. Comparison of acidification and soil organic carbon determination for semihumid soils in North China[J]. Chinese Journal of Soil Science, 2014, 45(4): 863−870. doi: 10.19336/j.cnki.trtb.2014.04.016
[9]	谢娟, 张心昱, 王秋凤, 等. 燃烧法与化学氧化法测定不同pH土壤有机碳之比较[J]. 土壤通报, 2013, 44(2): 333−337. doi: 10.19336/j.cnki.trtb.2013.02.012 Xie J, Zhang X Y, Wang Q F. et al. Comparative determination of soil organic carbon with different pH using combustion method and chemical oxidation method[J]. Chinese Journal of Soil Science, 2013, 44(2): 333−337. doi: 10.19336/j.cnki.trtb.2013.02.012
[10]	陆永欢, 戴全厚, 姚一文, 等. 工程堆积体植被类型对土壤有机碳组分特征及影响因素研究[J]. 水土保持学报, 2022, 36(6): 316−322. doi: 10.13870/j.cnki.stbcxb.2022.06.038 Lu Y H, Dai Q H, Yao Y W, et al. Effects of vegetation types on soil organic carbon components characteristics and its influencing factors in engineering deposits[J]. Journal of Soil and Water Conservation, 2022, 36(6): 316−322. doi: 10.13870/j.cnki.stbcxb.2022.06.038
[11]	王梦雅, 符云鹏, 黄婷婷, 等. 等碳量添加不同有机物料对土壤有机碳组分及土壤呼吸的影响[J]. 中国烟草学报, 2018, 24(2): 65−73. doi: 10.16472/j.chinatobacco.2017.331 Wang M Y, Fu Y P, Huang T T, et al. Effects of organic material application on organic carbon in and respiration of soil[J]. Acta Tabacaria Sinica, 2018, 24(2): 65−73. doi: 10.16472/j.chinatobacco.2017.331
[12]	李传福, 朱桃川, 明玉飞, 等. 有机肥与脱硫石膏对黄河三角洲盐碱地土壤团聚体及其有机碳组分的影响[J]. 生态环境学报, 2023, 32(5): 878−888. doi: 10.16258/j.cnki.1674-5906.2023.05.006 Li C F, Zhu T C, Ming Y F, et al. Effect of organic fertilizer and desulphurized gypsum on soil aggregates and organic carbon and its fractions contents in the saline-alkali soil of the Yellow River Delta[J]. Ecology and Environment Sinences, 2023, 32(5): 878−888. doi: 10.16258/j.cnki.1674-5906.2023.05.006
[13]	于雯泉, 钟少军. 海洋沉积物有机碳分析方法中干燥预处理过程人为误差的发现及其意义[J]. 环境科学学报, 2007, 27(5): 861−867. doi: 10.3321/j.issn:0253-2468.2007.05.025 Yu W Q, Zhong S J. Freeze-drying pretreatment improves organic carbon determinations of marine sediments[J]. Acta Scientiae Circumstantiae Stantiae, 2007, 27(5): 861−867. doi: 10.3321/j.issn:0253-2468.2007.05.025
[14]	井玉丹, 王家嘉, 裴欢, 等. 烘箱加热法测定土壤有机质的改进研究[J]. 中国土壤与肥料, 2023(10): 245−250. doi: 10.11838/sfsc.1673-6257.22615 Jing Y D, Wang J J, Pei H, et al. Improvement of oven heating method for determination of soil organic matter[J]. Soil Fertilizer Sciences in China, 2023(10): 245−250. doi: 10.11838/sfsc.1673-6257.22615
[15]	郝国辉, 邵劲松. 土壤有机质含量测定方法的改进研究[J]. 农业资源与环境学报, 2014, 31(2): 202−204. doi: 10.13254/j.jare.2014.0007 Hao G H, Shao J S. Improvement research on the measurement method for organic matter content in soil[J]. Journal of Agricultural Resources and Environment, 2014, 31(2): 202−204. doi: 10.13254/j.jare.2014.0007
[16]	刘昌岭, 朱志刚, 贺行良, 等. 重铬酸钾氧化-硫酸亚铁滴定法快速测定海洋沉积物中有机碳[J]. 岩矿测试, 2007, 26(3): 205−208. doi: 10.3969/j.issn.0254-5357.2007.03.008 Liu C L, Zhu Z G, He X L, et al. Rapid determination of organic carbon in marine sediment samples by potassium dichromate oxidation-ferrous sulphate titrimetry[J]. Rock and Mineral Analysis, 2007, 26(3): 205−208. doi: 10.3969/j.issn.0254-5357.2007.03.008
[17]	孙晗杰, 李铁刚, 于心科. 自动电位滴定仪测定海洋沉积物中碳酸盐百分含量[J]. 海洋地质与第四纪地质, 2012, 32(5): 157−162. doi: 10.3724/SP.J.1140.2012.05157 Sun H J, Li T G, Yu X K. The determination of carbonate content in marine sediments by automatic potentiometric titrator[J]. Marine Geology & Quaternary Geology, 2012, 32(5): 157−162. doi: 10.3724/SP.J.1140.2012.05157
[18]	赵文杰, 马明, 张珂, 等. 自动电位滴定仪应用于地下水六项指标的连续滴定[J]. 岩矿测试, 2018, 37(5): 580−585. doi: 10.15898/j.cnki.11-2131/td.201711060176 Zhao W J, Ma M, Zhang K, et al. Application of automatic potentiometric titrator in continuous titration of six indices in groundwater[J]. Rock and Mineral Analysis, 2018, 37(5): 580−585. doi: 10.15898/j.cnki.11-2131/td.201711060176
[19]	王兵, 高丰蕾, 杨佩华, 等. 自动电位滴定仪应用于测定海洋沉积物中有机碳的可行性研究[J]. 岩矿测试, 2016, 35(4): 402−408. doi: 10.15898/j.cnki.11-2131/td.2016.04.011 Wang B, Gao F L, Yang P H, et al. Feasibility study on the application of automatic potentiometric titrator in the measurement of organic carbon in marine sediments[J]. Rock and Mineral Analysis, 2016, 35(4): 402−408. doi: 10.15898/j.cnki.11-2131/td.2016.04.011
[20]	郝会军, 杨俐苹, 金健运. 自动电位滴定法测定土壤有机质含量[J]. 中国土壤与肥料, 2011(1): 83−87. doi: 10.3969/j.issn.1673-6257.2011.01.019 Hao H J, Yang L P, Jin J Y. Determination of soil organic matter by automatically potentiometric titration method[J]. Soils and Fertilizers Sciences in China, 2011(1): 83−87. doi: 10.3969/j.issn.1673-6257.2011.01.019
[21]	杨娥女, 王宝荣, 姚宏佳, 等. 黄土高原生物土壤结皮发育过程中颗粒态和矿物结合态有机碳变化特征[J]. 水土保持研究, 2023, 30(1): 25−33, 40. doi: 10.13869/j.cnki.rswc.20220427.001 Yang E N, Wang B R, Yao H J, et al. Dynamics of particulate and mineral-associated organic carbon during the development of biological soil crusts in the Loess Plateau[J]. Research of Soil and Water Conservation, 2023, 30(1): 25−33, 40. doi: 10.13869/j.cnki.rswc.20220427.001
[22]	张睿博, 汪金松, 王全成, 等. 土壤颗粒态有机碳与矿物结合态有机碳对气候变暖响应的研究进展[J]. 地理科学进展, 2023(12): 2471−2484. doi: 10.18306/dlkxjz.2023.12.015 Zhang R B, Wang J S, Wang Q C. et al. Responses of soil particulate and mineral associated organic carbon to climate warming: A review[J]. Progress in Geography, 2023(12): 2471−2484. doi: 10.18306/dlkxjz.2023.12.015
[23]	徐嘉晖, 高雷, 孙颖, 等. 大兴安岭森林土壤矿物结合态有机碳与黑碳的分布及土壤固碳潜力[J]. 土壤学报, 2018, 55(1): 236−246. doi: 10.11766/trxb201708080194 Xu J H, Gao L, Sun Y, et al. Distribution of mineral-bonded organic carbon and black carbon in forest soils of Great Xing’an Mountains, China and carbon sequestration potential of the soils[J]. Acta Pedological Sinica, 2018, 55(1): 236−246. doi: 10.11766/trxb201708080194