土壤阳离子交换量的测定离子选择电极法编制说明

1本方法起草单位有：重庆为讯科学仪器有限本方法参与单位有：西南大学、重庆市九升检测技术2.资料收集和调研：工作组成员负责检索、查询和收集国内外相关标准和3.组织开展实验研究和方法验证：标准起草工作组根据确定的技术方案，代表性标准土壤、12种典型地带性土壤样品进行分析，确定具体的技术内容及25.广泛征集高校、科研院所、企业单位等相关领域的专家意见，对专家意本标准主要按照GB/T1.1-2020《标GB/T8170《数值修约规则与极限数值的表示和判定》和HJ168《环境监测分析结果计算和表示、精密度和准确度、质量保证和质32]+并借助于快速的“表面酸碱反应”来调节悬液pH，并使[≡Si-O]-‧H+快速转换成(转换数量都由pH决定)。所释放的负电荷被Na+平衡。根据轨道非对称杂化理Na+吸附量就是该pH条件下的阳离子交换量。土壤胶体吸附的所有可交换的阳43.7四硼酸钠（Na2B4O7·10H2O）。与饱和溴化钠（或氯化钠加蔗糖）溶液3.90.1mol/LHCl溶液：量取浓盐酸83.100.001mol/LHCl溶液：移取1.00mL盐酸溶液（3.9转移至103.120.100mol/L钠离子标准溶液：称取5.844g氯化钠（3.3纯水溶解3.140.001mol/L钠离子标准溶液：移取10.00mL0.010mol/L钠标准溶液注：上述pH标准缓冲溶液于冰箱中4℃冷藏可保存2～3个月。发现有混54.4尼龙标准筛：孔径2mm、04.11聚乙烯瓶（具盖、密封）。（1）称取一定质量过2mm孔径筛的风干土壤样品于离心管中；准确称取6m1−(m2−m0)m17电极垂直悬空放入含有磁子的缓冲溶液中（pH电极玻璃球需放入液面以下2~3实测电位值记做ENa(mV)。Na—标液中Na+浓度，mol/L；Na+标准曲线相关性系数R至少需达到0.测土壤悬液中钠离子电极mV值，即可确定待测悬液中Na+活度。8下一步操作；如pH＜11.80，则需继续加入适量的0.020mol/LNaOH溶液调节pH（每次加液后都需搅拌10min后再测pH）至12.00±0.20范围内（记录加入）（继续插入悬液不移出调节悬液pH至某一目标（5）将pH电极取出（电极可不清洗悬液中放入钠离子电极与温度传定钠离子电极的电位值ENa与溶液温度T并记录。注：记录每次调节pH值所消耗醋酸溶液的体积，结果计算时应累加调节到目标pH值的醋酸溶液体积，记为V2。在迭代运算中，将测定Na+活度设定为Na+初始浓度值，即cNa(0)=aNa，则9同理，按上述过程反复进行迭代运算，直到第k次与第k+1次的结果相差Na+浓度cNa。0.001—体积mL换算为L系数；5—mol(+)/g换算为cmol(+)/kg系数。MDL=t(n−1,0.99)×SMDL—方法检出限；）；S—n次平行测定的标准偏差。平行测定次数（n）自由度（n-1）t（n-1,0.99）763.143872.998982.89692.8212.7642.60221202.528pH注：最终方法检出限取验证单位中方法检出限最高值。Si—第i个实验室对某一样品测试的标准偏差；RSDi—第i个实验室对某一样品测试的相对标准偏差也就是精密度。检测单位样品编号标土参考值检测结果（cmol(+)/kg）平均值（cmol(+)/kg）RSDRe结果1结果2结果3结果4结果5结果6结果7九升检测ASA-5b10.5±1.013.89±0.412.0932.24ASA-11a16.50±0.662.18-2.92SAS-422.7±1.221.2021.3021.3021.3021.5021.8021.5021.41±0.390.88-5.66ASA-6b9.0±0.89.189.699.869.699.79±0.612.918.75ASA-4b13.8±1.215.94±0.133.05ASA-1819.8±1.220.2120.223.20-1.28SAS-79.0±1.08.158.208.298.308.318.368.348.28±0.130.85-8.02ASA-2b14.0±0.912.92±0.210.66-7.71SAS-822.5±2.020.8322.7622.0122.0122.5222.3022.6922.16±1.332.75-1.51为讯仪ASA-5b10.5±1.012.25±0.713.32ASA-11a16.38±1.034.19-3.62SAS-422.7±1.221.8921.9021.8821.8921.8421.8321.8421.87±0.04-3.67器ASA-6b9.0±0.89.689.178.659.178.999.339.29±0.734.493.19ASA-4b13.8±1.215.79±0.634.16ASA-1819.8±1.220.1019.58±0.49-1.13SAS-79.0±1.07.917.757.928.087.777.767.917.87±0.12-12.54ASA-2b14.0±0.913.05±0.39-6.79SAS-822.5±2.022.2623.5922.9223.2523.5923.5821.9323.02±1.092.742.30ASA-5b10.5±1.011.91±0.784.02ASA-11a17.08±0.895.610.45SAS-422.7±1.220.4321.4321.7921.5121.5121.5121.4921.38±0.95-5.81ASA-6b9.0±0.89.709.2010.27±1.075.48ASA-4b13.8±1.213.93±1.276.840.94ASA-1819.8±1.221.9221.9221.9222.2621.2222.5821.9021.96±0.74SAS-79.0±1.08.228.238.078.238.228.378.528.27±0.25-8.16ASA-2b14.0±0.913.93±0.250.94-0.51SAS-822.5±2.023.9124.8823.5623.8922.5524.2022.8923.70±1.183.085.32样品编号标土参考值检测结果（cmol(+)/kg）平均值RSDRe结果1结果2结果3结果4结果5结果6结果7ASA-5b10.5±1.012.68±0.3720.79ASA-11a16.65±0.43-2.03SAS-422.7±1.221.1721.5421.6621.5721.6221.7121.7421.57±0.400.76-5.05ASA-6b9.0±0.89.639.529.989.819.759.809.979.78±0.268.68ASA-4b13.8±1.215.22±0.642.72ASA-1819.8±1.220.2920.5020.3820.4020.1720.7420.0420.36±0.382.83SAS-79.0±1.08.097.998.098.208.108.168.260.81-9.57ASA-2b14.0±0.913.30±0.230.81-5.00SAS-822.5±2.022.3323.7422.8323.0522.8923.3622.5022.96±0.782.04检测单位样品名称结果1结果2结果3平均值RSD（%）为讯仪器江西红壤江苏盐碱土5.826.065.815.90±0.16山东棕壤18.24±0.34砂黄土8.928.288.288.49±0.433.55黑垆土9.189.959.489.54±0.413.32褐土12.83±0.432.57风沙土5.285.465.29±0.172.63黄绵土6.616.306.286.40±0.212.36塿土9.839.849.609.76±0.18砖红壤7.107.427.097.20±0.222.13紫色土21.8721.8922.2121.99±0.220.71黑土26.6125.3824.7625.58±1.033.01西南大学江西红壤10.88±0.27江苏盐碱土7.527.307.537.45±0.15山东棕壤19.68±0.170.60砂黄土7.987.998.308.09±0.21黑垆土8.038.028.488.18±0.302.62褐土14.84±0.170.83风沙土4.444.614.784.61±0.173.01黄绵土9.249.959.649.61±0.403.02塿土12.03±0.24砖红壤8.828.138.478.47±0.353.32紫色土23.8624.5024.8324.40±0.54黑土24.1824.1824.7824.38±0.40九升检测江西红壤10.92±0.24江苏盐碱土6.626.536.766.64±0.12山东棕壤16.95±1.925.05砂黄土6.377.378.017.25±0.889.31黑垆土8.808.338.568.56±0.242.24褐土10.80±0.413.03风沙土4.093.924.604.20±0.406.87黄绵土6.926.906.906.91±0.01塿土0.89砖红壤7.797.797.447.67±0.232.15紫色土21.8922.2221.8922.00±0.220.71黑土21.6022.9322.22±0.712.46样品名称结果1结果2结果3平均值RSD江西红壤10.98±0.040.22江苏盐碱土6.656.636.706.66±0.040.44山东棕壤18.29±0.40砂黄土7.767.888.207.94±0.262.33黑垆土8.678.778.848.76±0.090.79褐土12.83±0.080.43风沙土4.604.554.954.70±0.253.74黄绵土7.597.727.617.64±0.080.74塿土11.32±0.010.02砖红壤7.907.787.677.78±0.12紫色土22.5422.8722.9822.80±0.260.