Development of Nitrogen and Organic Carbon Reference Materials for China Offshore Marine Sediments
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摘要: 我国海洋沉积物的研究近几年发展较快,但是缺少有定值的氮、有机碳标准物质。本文针对及其匮乏的氮、有机碳国家二级标准物质进行了我国近海沉积物总氮(TN)、总碳(TC)、总有机碳(TOC)含量的分析标准参考物质的研制。研究样品采自“我国近海海洋综合调查与评价”专项提供的表层沉积物,经过冷冻干燥、研磨至74 μm,使用元素分析仪和氧化热解-气相色谱法分析总氮和总碳的含量;使用元素分析仪和氧化热解-电位法分析总有机碳的含量,制备了一系列16个有定值的总氮、总碳、总有机碳含量的近海沉积物标准物质。样品在均匀性检验中,F的实测值小于临界值,相对偏差较小,样品的均匀性较好。在稳定性检验方面,两年内多次测定的分析结果无方向性变化,统计计算结果显示稳定性良好。本文研制的这16个近海沉积物标准物质在3家实验室进行了联合定值,按照ISO导则35和国家一级标准物质研制规范,给出了该系列标准物质总氮、总碳、总有机碳含量的标准值和不确定度。这批标准物质分为不同海区,不同海区的标准物质又分为不同的沉积物类型,研制的不同海区不同沉积物类型的标准物质对现有的海洋沉积物标准物质进行了有效的补充。Abstract: The study of marine sediments in China has developed rapidly in recent years, but the standard materials with certified values for nitrogen organic and carbon are relatively lacking. In light of this the standard materials for total nitrogen (TN), total carbon (TC) and total organic carbon (TOC) have been prepared and are reported in this paper. The samples were collected from the surface sediment for the ‘China Offshore Marine Integrated Investigation and Evaluation Project’. After being frozen and dried, the samples were ground into 74 μm. The contents of TN and TC were measured by using an elemental analyzer and oxidation of pyrolysis Gas Chromatography. The content of TOC was measured by using an elemental analyzer and the oxidative pyrolysis potential method. A series of 16 sediment reference materials with certified values of TN, TC and TOC content has been developed. In the uniformity test, the measured values are less than the critical value of F, relative deviation is small, indicating better uniformity. Good stability was verified by repeating the analysis multiple times within the past two years, without any changes. The 16 offshore sediment reference materials were tested in three laboratories, following the ISO guide 35 and national level standard materials specifications. The series of standard materials provided certified values of TN, TC and TOC with uncertainties. The samples are from different areas and different sediment types. The results show that different sea sediment types of standard materials are essential and this work contributes to existing marine sediment reference materials.
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Key words:
- offshore marine sediments /
- total nitrogen /
- total carbon /
- total organic carbon /
- standard materials /
- uniformity /
- stability
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表 1 均匀性检验方差分析结果
Table 1. Variance analysis results of homogeneity test
样品编号 总氮 总碳 总有机碳 x/% RSD/% F测 x/% RSD/% F测 x/% RSD/% F测 GSBS-1 0.023 4.18 2.29 0.099 0.91 0.66 0.047 2.81 1.66 GSBS-2 0.076 2.19 1.68 1.081 1.12 0.71 0.644 0.56 1.29 GSBS-3 0.040 1.76 2.33 0.540 0.62 0.15 0.281 2.43 2.32 GSBS-4 0.047 1.46 1.34 1.873 0.21 1.13 0.620 0.42 1.62 GSBS-5 0.027 4.01 2.01 1.015 0.76 1.92 0.090 1.57 2.30 GSYS-1 0.063 2.88 1.83 1.306 1.74 1.78 0.374 2.74 2.06 GSYS-2 0.058 1.88 2.10 1.298 1.29 1.64 0.443 2.48 1.76 GSYS-3 0.024 6.28 1.40 0.577 2.42 0.74 0.068 2.24 1.72 GSYS-4 0.034 2.72 2.28 1.182 0.70 1.59 0.124 2.88 2.23 GSYS-5 0.058 2.48 2.31 1.249 0.77 0.64 0.382 1.39 1.56 GSYS-6 0.047 2.60 2.17 1.666 3.75 2.03 0.382 1.86 2.00 GSES-1 0.068 2.62 2.32 1.225 2.62 2.26 0.434 0.85 1.73 GSES-2 0.081 2.61 1.36 1.230 2.62 0.44 0.517 1.06 2.24 GSSS-1 0.024 4.17 1.61 0.507 0.89 0.10 0.045 0.84 1.01 GSSS-2 0.076 1.79 1.89 1.419 0.70 1.96 0.842 1.24 2.53 GSSS-3 0.100 2.97 2.36 2.014 0.14 0.16 0.909 0.19 2.39 表 2 精密度监控限
Table 2. The monitoring limits of precision
含量范围 RSD/% 1 ∶ 5万 1 ∶ 20万 检出限3倍以内 ≤40 ≤35 检出限3倍以上 ≤25 ≤23 1%~5% - ≤8 >5% - ≤3 表 3 分析标准物质的总氮、总碳、总有机碳含量的精密度
Table 3. Precision tests of the reference materials
样品编号 总氮 总碳 总有机碳 x/% RSD/% x/% RSD/% x/% RSD/% GSBS-1 0.022 3.5 0.099 0.8 0.047 2.9 GSBS-2 0.076 2.6 1.085 0.8 0.643 0.5 GSBS-3 0.041 1.4 0.541 0.5 0.281 2.2 GSBS-4 0.047 1.3 1.875 0.2 0.620 0.4 GSBS-5 0.027 3.7 1.017 0.5 0.091 1.6 GSYS-1 0.064 2.2 1.298 1.25 0.376 2.7 GSYS-2 0.057 1.9 1.296 0.3 0.441 1.8 GSYS-3 0.024 7.5 0.579 1.7 0.068 2.2 GSYS-4 0.034 2.8 1.182 0.6 0.124 2.6 GSYS-5 0.058 2.5 1.250 0.7 0.381 1.5 GSYS-6 0.047 2.6 1.647 1.0 0.383 2.0 GSES-1 0.068 3.0 1.229 1.0 0.433 0.9 GSES-2 0.080 1.1 1.235 0.5 0.517 1.0 GSSS-1 0.024 4.2 0.506 0.6 0.046 1.0 GSSS-2 0.076 1.2 1.423 0.7 0.839 1.2 GSSS-3 0.099 2.6 2.014 0.2 0.908 0.1 表 4 各标准物质定值数据的离群数据检验结果
Table 4. Analytical results of discrete data for reference materials
样品编号 总氮 总碳 总有机碳 $$ SD t1 t2 $$ SD t1 t2 $$ SD t1 t2 GSBS-1 0.023 0.001 1.37 1.31 0.101 0.002 2.38 1.40 0.047 0.001 1.85 1.38 GSBS-2 0.076 0.001 1.95 1.56 1.082 0.015 1.27 2.53 0.643 0.004 2.07 2.46 GSBS-3 0.040 0.001 1.38 1.63 0.535 0.008 2.17 1.92 0.280 0.007 1.54 1.42 GSBS-4 0.047 0.001 2.31 1.56 1.870 0.005 1.81 1.95 0.621 0.003 2.29 1.97 GSBS-5 0.027 0.001 1.69 1.34 1.013 0.007 1.77 2.03 0.090 0.001 2.11 1.43 GSYS-1 0.063 0.002 2.14 1.34 1.312 0.021 1.90 1.79 0.374 0.009 1.25 2.09 GSYS-2 0.058 0.001 1.13 1.83 1.302 0.009 1.77 1.62 0.447 0.012 1.83 1.04 GSYS-3 0.024 0.002 1.32 1.86 0.577 0.014 1.66 1.94 0.068 0.001 1.85 1.28 GSYS-4 0.033 0.001 1.88 1.47 1.181 0.008 2.05 2.22 0.124 0.003 1.83 0.86 GSYS-5 0.058 0.001 2.26 1.30 1.250 0.008 1.71 1.19 0.381 0.005 1.46 1.80 GSYS-6 0.045 0.002 1.79 1.64 1.657 0.018 1.65 2.43 0.381 0.007 2.00 1.06 GSES-1 0.067 0.002 2.64 1.47 1.223 0.010 2.07 1.66 0.434 0.004 1.16 2.16 GSES-2 0.081 0.002 2.38 0.96 1.222 0.014 2.03 1.92 0.518 0.005 1.63 1.21 GSSS-1 0.024 0.001 1.62 1.64 0.506 0.016 2.36 1.24 0.046 0.001 2.42 1.02 GSSS-2 0.075 0.001 2.10 2.03 1.416 0.010 2.00 1.34 0.842 0.010 1.723 1.846 GSSS-3 0.100 0.003 1.94 2.04 2.018 0.008 1.50 2.08 0.909 0.002 1.445 1.555 表 5 正态性检验结果
Table 5. Normal inspection data for certified values
项目 统计量W GSBS-1 GSBS-2 GSBS-3 GSBS-4 GSBS-5 GSYS-1 GSYS-2 GSYS-3 总氮 0.933 0.951 0.963 0.984 0.936 0.929 0.928 0.936 总碳 0.962 0.963 0.955 0.957 0.934 0.951 0.961 0.974 总有机碳 0.95 0.96 0.956 0.933 0.943 0.951 0.931 0.954 项目 GSYS-4 GSYS-5 GSYS-6 GSES-1 GSES-2 GSSS-1 GSSS-2 GSSS-3 总氮 0.946 0.958 0.929 0.936 0.933 0.951 0.955 0.945 总碳 0.982 0.966 0.965 0.964 0.933 0.953 0.964 0.987 总有机碳 0.981 0.962 0.931 0.974 0.962 0.933 0.951 0.93 W(30,0.95) 0.927 表 6 各标准物质的标准值和不确定度
Table 6. Certified values and uncertainty of the standard samples
样品编号 w/% 总氮 总碳 总有机碳 GSBS-1 0.023±0.003 0.1±0.01 0.047±0.001 GSBS-2 0.076±0.002 1.08±0.03 0.64±0.006 GSBS-3 0.04±0.002 0.54±0.02 0.28±0.004 GSBS-4 0.047±0.002 1.87±0.05 0.62±0.003 GSBS-5 0.027±0.002 1.02±0.02 0.09±0.001 GSYS-1 0.063±0.002 1.31±0.02 0.38±0.009 GSYS-2 0.058±0.001 1.3±0.01 0.45±0.01 GSYS-3 0.024±0.002 0.58±0.02 0.068±0.001 GSYS-4 0.033±0.001 1.18±0.01 0.13±0.003 GSYS-5 0.058±0.001 1.25±0.01 0.38±0.005 GSYS-6 0.045±0.002 1.66±0.02 0.38±0.006 GSES-1 0.067±0.002 1.23±0.01 0.44±0.004 GSES-2 0.081±0.002 1.22±0.01 0.52±0.005 GSSS-1 0.024±0.001 0.51±0.01 0.046±0.001 GSSS-2 0.075±0.002 1.42±0.01 0.84±0.011 GSSS-3 0.1±0.003 2.02±0.01 0.91±0.002 -
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