Determination of 23 Elements in Biological Samples by Wavelength Dispersion X-ray Fluorescence Spectrometry with High Pressure Pressed Powder Pellet Preparation
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摘要:
应用X射线荧光光谱法(XRF)分析生物样品, 采用传统低压粉末制样方法(压强220~440 MPa)难以将样品压制成符合测定需要的样片, 样片表面粗糙, 粉末容易脱落, 污染XRF仪器样品室, 影响仪器的长期稳定性。本文采用高压粉末制样方法在1760 MPa下压制则完全克服了低压制样的弊端, 制备的样片表面光滑、致密, 大幅改善了制样重现性, 5次制样重现性为0.1%~2.6%, 且降低了仪器的维护成本。在此基础上, 建立了波长色散X射线荧光光谱法直接测定生物样品中23种主次量元素(Al、Ca、Cl、K、Mg、Na、P、S、Si、Ba、Br、Co、Cr、Cu、Fe、Mn、Ni、Pb、Rb、Sr、Ti、V、Zn)的分析方法, 采用经验系数法、散射线内标法和峰背景作内标校正基体效应, 大部分元素的方法精密度提高至0.4%~11.3%, 检出限为0.08~140.96 μg/g。经国家一级生物标准物质验证, 表明方法准确可靠, 能满足日常分析要求。
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关键词:
- 生物样品 /
- 主次量元素 /
- 高压制样 /
- 波长色散X射线荧光光谱法 /
- 基体效应
Abstract:In the determination of biological samples by X-ray Fluorescence Spectrometry, sample powder pellets pressed by traditional sample preparation technique at 220-440 MPa are not compact and smooth, so the sample room of X-ray Fluorescence Spectrometry becomes contaminated by dropped sample powder, which can then influence long term stability. Biological sample powder can be pressed into smooth and compact pellets using high pressure at 1760 MPa, therefore the sample preparation reproducibility is improved to 0.1%-2.6% (RSD, n=5). A method for direct determination of 23 major and minor elements (Al, Ca, Cl, K, Mg, Na, P, S, Si, Ba, Br, Co, Cr, Cu, Fe, Mn, Ni, Pb, Rb, Sr, Ti, V and Zn) in biological samples by Wavelength Dispersion X-ray Fluorescence Spectrometry was established on this sample preparation basis. The matrix effects can be corrected by using Rh-Kα(from the X-ray tube target) Compton-scattered radiation and by using the background as the internal standard. The precision of the method is 0.1%-11.3% (RSD) for most elements and the detection limits is 0.08-140.96 μg/g. The feasibility of the proposed method was tested by analyzing several national biological standard materials; the results obtained were consistent with the certified values.
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表 1 XRF仪器分析条件
Table 1. Working conditions of elements by XRF instrument
元
素分析线 分析晶体 准直器
(μm)探测器 电压
(kV)电流
(mA)2θ
(°)背景
(°)PHA LL UL Cl Kα Ge 111-C 550 Flow 30 120 92.7540 1.8174 27 73 S Kα Ge 111-C 550 Flow 30 120 110.6194 1.9288 27 73 P Kα Ge 111-C 550 Flow 30 120 140.9836 1.8828 27 72 Al Kα PE 002-C 550 Flow 30 120 144.9720 2.2774 26 74 Si Kα PE 002-C 550 Flow 30 120 109.1146 2.2478 26 75 Mg Kα PX1 550 Flow 30 120 22.4154 2.1348 26 74 Na Kα PX1 550 Flow 30 120 27.0702 2.3548 25 74 K Kα PX10 150 Flow 30 120 136.6580 3.1826 31 69 Ca Kα PX10 150 Flow 30 120 113.1406 1.7688 32 69 Ti Kα PX10 150 Flow 40 90 86.1630 1.9130 36 66 Ba Lα PX10 150 Flow 40 90 87.1962 1.4600 33 64 Cr Kα PX10 150 Duplex 60 60 69.3442 1.4420 12 67 V Kα PX10 150 Duplex 60 60 76.9348 1.3334 11 66 Co Kα PX10 150 Duplex 60 60 52.8008 1.2536 16 66 Cu Kα PX10 150 Duplex 60 60 45.0272 0.4804 19 66 Fe Kα PX10 150 Duplex 60 60 57.5218 1.4472 15 68 Mn Kα PX10 150 Duplex 60 60 62.9972 1.5536 14 68 Ni Kα PX10 150 Duplex 60 60 48.6372 -0.6842 19 62 Rb Kα PX10 150 Hiper Scint 60 60 26.5814 0.4576 20 78 Pb Lβ1 PX10 150 Hiper Scint 60 60 28.2408 0.5944 22 75 Zn Kα PX10 150 Hiper Scint 60 60 41.7896 0.7828 21 78 Br Kα PX10 150 Hiper Scint 60 60 29.9456 -0.4110 21 75 Sr Kα PX10 150 Hiper Scint 60 60 25.1414 0.5098 21 78 Rh Kα-C PX10 150 Hiper Scint 60 60 18.4798 26 73 注:PHA为脉冲高度分析器,LL为分析下限,UL为分析上限。 表 2 标准物质中元素含量范围
Table 2. Concentration range of elements in standard materials
元素 含量范围
(μg/g)元素 含量范围
(%)Ba 0.24~98 Al 0.003~2.00 Br 0.27~92 Ca 0.022~4.20 Co 0.01~0.63 Cl 0.018~3.54 Cr 0.13~2.6 K 0.002~3.36 Cu 0.51~52 Mg 0.014~0.552 Fe 7.8~1450 Na 0.0077~2.17 Mn 0.51~1170 S 0.11~4.19 Ni 0.10~5.4 Si 0.013~1.10 Pb 0.07~11.1 P 0.014~1.17 Rb 0.06~89 Sr 0.51~213 Ti 3.3~102 V 0.06~4.2 Zn 11.1~211 表 3 高压和低压制样重现性的比较
Table 3. Comparison of reproducibility using high pressure (1760 MPa) and low pressure (440 MPa)
元素 1760 MPa(高压制样) 440 MPa(低压制样) I1760 MPa 荧光强度平均值
(kcps)RSD
(%)荧光强度平均值
(cps)RSD
(%)I440 MPa Al 7.766 0.6 7.635 1.5 1.02 Ba 0.339 0.8 0.337 0.9 1.01 Br 9.364 0.3 9.260 0.4 1.01 Ca 194.450 0.1 193.085 0.2 1.01 Cl 3.467 0.5 3.464 1.2 1.00 Co 0.288 0.7 0.281 1.4 1.03 Cr 0.556 0.4 0.548 0.9 1.02 Cu 0.837 0.4 0.825 0.7 1.01 Fe 5.597 0.2 5.486 0.2 1.02 K 31.300 0.1 31.140 0.3 1.01 Mg 14.424 0.2 14.167 0.3 1.02 Mn 0.379 0.5 0.374 1.3 1.01 Na 0.559 1.8 0.555 2.8 1.01 Ni 0.327 0.8 0.321 1.0 1.02 P 28.754 0.2 28.251 0.4 1.02 Pb 12.081 0.5 11.910 0.8 1.01 Rb 13.935 2.6 14.164 6.2 0.98 S 76.236 0.2 75.245 0.2 1.01 Si 20.906 0.3 20.765 1.1 1.01 Sr 69.957 0.5 69.433 0.5 1.01 Ti 0.409 0.9 0.404 1.1 1.01 V 0.350 0.5 0.341 0.8 1.03 Zn 3.038 0.5 3.009 0.7 1.01 表 4 内标的影响
Table 4. Effects of internal standard
元
素RMS 元
素RMS 无内标 Rh Kα康普顿
作内标元素背景
作内标无内标 Rh Kα康普顿
作内标元素背景
作内标Al 0.01605 0.00741 0.02321 Cr 0.00004 0.00002 0.00002 Ca 0.09714 0.04875 0.02054 Cu 0.00019 0.00005 0.00003 Cl 0.02930 0.04319 0.01777 Fe 0.00571 0.00231 0.00343 K 0.26352 0.04592 0.22314 Mn 0.00072 0.00014 0.00034 Mg 0.01100 0.02270 0.04761 Ni 0.00002 0.00001 0.00002 Na 0.03162 0.06373 0.06579 Pb 0.00014 0.00003 0.00003 P 0.03754 0.02680 0.04040 Rb 0.00019 0.00006 0.00006 S 0.02710 0.06146 0.22249 Sr 0.00067 0.00016 0.00016 Si 0.02050 0.01638 0.03431 Ti 0.00029 0.00029 0.00026 Ba 0.00052 0.00021 0.00023 V 0.00002 0.00001 0.00001 Br 0.00007 0.00002 0.00002 Zn 0.00047 0.00014 0.00017 Co 0.00001 0.00001 0.00001 表 5 方法检出限
Table 5. Detection limits of the method
元素1760 MPa
高压制样
检出限(μg/g)440 MPa
低压制样
检出限(μg/g)元素 1760 MPa
高压制样
检出限(μg/g)440 MPa
低压制样
检出限(μg/g)Al 12.99 14.56 Cr 0.26 0.26 Ca 8.29 10.29 Cu 0.21 0.21 Cl 22.78 25.3 Fe 0.53 0.55 K 8.29 11.2 Mn 0.52 0.55 Mg 12.99 15.12 Ni 0.23 0.22 Na 28.28 31.53 Pb 0.14 0.13 P 12.99 15.45 Rb 0.17 0.16 S 14.79 16.15 Sr 0.16 0.18 Si 140.96 145.52 Ti 0.81 0.88 Ba 1.37 1.45 V 0.08 0.08 Br 0.28 0.32 Zn 0.43 0.42 Co 0.10 0.11 表 6 方法精密度
Table 6. Precision tests of the method
元素 GBW 10015
(菠菜)GBW 10020
(柑橘叶)GBW 10021
(豆角)测定值
(%)RSD
(%)测定值
(%)RSD
(%)测定值
(%)RSD
(%)Al 0.061 2.0 0.115 1.3 0.041 2.9 Ca 0.618 0.6 4.443 0.1 0.683 0.5 Cl 1.117 0.4 0.03 1.5 0.142 0.9 K 2.445 0.4 0.727 0.2 2.312 0.5 Mg 0.552 0.4 0.232 0.4 0.336 0.5 Na 1.485 0.7 0.018 6.4 0.067 3.0 P 0.326 0.3 0.146 0.4 0.365 0.4 S 0.473 0.4 0.398 0.3 0.174 0.4 Si 0.216 2.0 0.416 2.4 0.227 3.0 元素 测定值
(μg/g)RSD
(%)测定值
(μg/g)RSD
(%)测定值
(μg/g)RSD
(%)Ba 8.56 11.1 100.82 2.0 10.37 11.3 Br 9.82 0.7 3.11 3.3 0.64 7.0 Co 0.18 14.8 0.26 19.1 0.21 26.0 Cr 1.45 15.3 1.18 22.6 0.69 26.2 Cu 8.22 1.3 6.64 1.1 9.22 1.1 Fe 545.81 2.0 469.31 1.5 325.69 2.4 Mn 40.52 0.8 29.33 1.4 29.6 1.3 Ni 0.92 10.4 1.0 15.3 4.22 2.2 Pb 10.19 5.8 9.17 4.6 0.9 15.5 Rb 28.97 0.3 3.5 4.5 9.45 0.8 Sr 83.55 0.2 170.11 0.2 55.61 0.5 Ti 29.96 2.1 37.3 1.6 16.45 5.7 V 0.8 7.3 1.23 3.2 0.45 10.7 Zn 34.37 0.9 18.45 2.2 31.42 2.8 表 7 方法准确度
Table 7. Accuracy tests of the method
元素 GBW 10023(紫菜) GBW 10052(绿茶) 测定值
(%)标准值
(%)相对误差
(%)测定值
(%)标准值
(%)相对误差
(%)Al 0.487 0.49 0.61 0.132 - - Ca 0.142 0.153 7.19 1.13 1.21 6.61 Cl 2.709 2.8 3.25 0.053 0.056 5.36 K 3.295 3.36 1.93 1.573 1.55 -1.48 Mg 0.404 0.4 -1.00 0.221 0.22 -0.45 Na 1.485 1.55 4.19 0.01 0.01 0.00 P 0.564 0.585 3.59 0.272 0.28 2.86 S 2.219 2.26 1.81 0.416 0.42 0.95 Si 0.848 0.83 -2.17 0.281 0.26 -8.08 元素 测定值
(μg/g)标准值
(μg/g)相对误差
(%)测定值
(μg/g)标准值
(μg/g)相对误差
(%)Ba 11.251 10.4 -8.18 40.368 41 1.54 Br 92.058 92 -0.06 3.169 2.9 -9.28 Co 0.572 0.63 9.21 0.284 0.3 5.33 Cr 2.068 2.4 13.83 1.191 0.92 -29.46 Cu 11.278 12.2 7.56 23.997 24 0.01 Fe 1440.285 1450 0.67 330.146 322 -2.53 Mn 63.514 68 6.60 1167.48 1170 0.22 Ni 2.492 2.25 -10.76 5.528 5.4 -2.37 Pb 1.952 2.05 4.78 2.026 1.6 -26.63 Rb 11.107 10.4 -6.80 89.105 89 -0.12 Sr 22.442 24 6.49 36.552 36 -1.53 Ti 90.812 92 1.29 20.743 21 1.22 V 4.009 4.2 4.55 0.671 0.6 -11.83 Zn 26.388 28 5.76 35.139 35 -0.40 -
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