土壤陽(yáng)離子交換量的測(cè)定離子選擇電極法編制說(shuō)明

1本方法起草單位有：重慶為訊科學(xué)儀器有限本方法參與單位有：西南大學(xué)、重慶市九升檢測(cè)技術(shù)2.資料收集和調(diào)研：工作組成員負(fù)責(zé)檢索、查詢和收集國(guó)內(nèi)外相關(guān)標(biāo)準(zhǔn)和3.組織開展實(shí)驗(yàn)研究和方法驗(yàn)證：標(biāo)準(zhǔn)起草工作組根據(jù)確定的技術(shù)方案，代表性標(biāo)準(zhǔn)土壤、12種典型地帶性土壤樣品進(jìn)行分析，確定具體的技術(shù)內(nèi)容及25.廣泛征集高校、科研院所、企業(yè)單位等相關(guān)領(lǐng)域的專家意見，對(duì)專家意本標(biāo)準(zhǔn)主要按照GB/T1.1-2020《標(biāo)GB/T8170《數(shù)值修約規(guī)則與極限數(shù)值的表示和判定》和HJ168《環(huán)境監(jiān)測(cè)分析結(jié)果計(jì)算和表示、精密度和準(zhǔn)確度、質(zhì)量保證和質(zhì)32]+并借助于快速的“表面酸堿反應(yīng)”來(lái)調(diào)節(jié)懸液pH，并使[≡Si-O]-?H+快速轉(zhuǎn)換成(轉(zhuǎn)換數(shù)量都由pH決定)。所釋放的負(fù)電荷被Na+平衡。根據(jù)軌道非對(duì)稱雜化理Na+吸附量就是該pH條件下的陽(yáng)離子交換量。土壤膠體吸附的所有可交換的陽(yáng)43.7四硼酸鈉（Na2B4O7·10H2O）。與飽和溴化鈉（或氯化鈉加蔗糖）溶液3.90.1mol/LHCl溶液：量取濃鹽酸83.100.001mol/LHCl溶液：移取1.00mL鹽酸溶液（3.9轉(zhuǎn)移至103.120.100mol/L鈉離子標(biāo)準(zhǔn)溶液：稱取5.844g氯化鈉（3.3純水溶解3.140.001mol/L鈉離子標(biāo)準(zhǔn)溶液：移取10.00mL0.010mol/L鈉標(biāo)準(zhǔn)溶液注：上述pH標(biāo)準(zhǔn)緩沖溶液于冰箱中4℃冷藏可保存2～3個(gè)月。發(fā)現(xiàn)有混54.4尼龍標(biāo)準(zhǔn)篩：孔徑2mm、04.11聚乙烯瓶（具蓋、密封）。（1）稱取一定質(zhì)量過(guò)2mm孔徑篩的風(fēng)干土壤樣品于離心管中；準(zhǔn)確稱取6m1?(m2?m0)m17電極垂直懸空放入含有磁子的緩沖溶液中（pH電極玻璃球需放入液面以下2~3實(shí)測(cè)電位值記做ENa(mV)。Na—標(biāo)液中Na+濃度，mol/L；Na+標(biāo)準(zhǔn)曲線相關(guān)性系數(shù)R至少需達(dá)到0.測(cè)土壤懸液中鈉離子電極mV值，即可確定待測(cè)懸液中Na+活度。8下一步操作；如pH＜11.80，則需繼續(xù)加入適量的0.020mol/LNaOH溶液調(diào)節(jié)pH（每次加液后都需攪拌10min后再測(cè)pH）至12.00±0.20范圍內(nèi)（記錄加入）（繼續(xù)插入懸液不移出調(diào)節(jié)懸液pH至某一目標(biāo)（5）將pH電極取出（電極可不清洗懸液中放入鈉離子電極與溫度傳定鈉離子電極的電位值ENa與溶液溫度T并記錄。注：記錄每次調(diào)節(jié)pH值所消耗醋酸溶液的體積，結(jié)果計(jì)算時(shí)應(yīng)累加調(diào)節(jié)到目標(biāo)pH值的醋酸溶液體積，記為V2。在迭代運(yùn)算中，將測(cè)定Na+活度設(shè)定為Na+初始濃度值，即cNa(0)=aNa，則9同理，按上述過(guò)程反復(fù)進(jìn)行迭代運(yùn)算，直到第k次與第k+1次的結(jié)果相差Na+濃度cNa。0.001—體積mL換算為L(zhǎng)系數(shù)；5—mol(+)/g換算為cmol(+)/kg系數(shù)。MDL=t(n?1,0.99)×SMDL—方法檢出限；）；S—n次平行測(cè)定的標(biāo)準(zhǔn)偏差。平行測(cè)定次數(shù)（n）自由度（n-1）t（n-1,0.99）763.143872.998982.89692.8212.7642.60221202.528pH注：最終方法檢出限取驗(yàn)證單位中方法檢出限最高值。Si—第i個(gè)實(shí)驗(yàn)室對(duì)某一樣品測(cè)試的標(biāo)準(zhǔn)偏差；RSDi—第i個(gè)實(shí)驗(yàn)室對(duì)某一樣品測(cè)試的相對(duì)標(biāo)準(zhǔn)偏差也就是精密度。檢測(cè)單位樣品編號(hào)標(biāo)土參考值檢測(cè)結(jié)果（cmol(+)/kg）平均值（cmol(+)/kg）RSDRe結(jié)果1結(jié)果2結(jié)果3結(jié)果4結(jié)果5結(jié)果6結(jié)果7九升檢測(cè)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為訊儀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樣品編號(hào)標(biāo)土參考值檢測(cè)結(jié)果（cmol(+)/kg）平均值RSDRe結(jié)果1結(jié)果2結(jié)果3結(jié)果4結(jié)果5結(jié)果6結(jié)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檢測(cè)單位樣品名稱結(jié)果1結(jié)果2結(jié)果3平均值RSD（%）為訊儀器江西紅壤江蘇鹽堿土5.826.065.815.90±0.16山東棕壤18.24±0.34砂黃土8.928.288.288.49±0.433.55黑壚土9.189.959.489.54±0.413.32褐土12.83±0.432.57風(fēng)沙土5.285.465.29±0.172.63黃綿土6.616.306.286.40±0.212.36塿土9.839.849.609.76±0.18磚紅壤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西南大學(xué)江西紅壤10.88±0.27江蘇鹽堿土7.527.307.537.45±0.15山東棕壤19.68±0.170.60砂黃土7.987.998.308.09±0.21黑壚土8.038.028.488.18±0.302.62褐土14.84±0.170.83風(fēng)沙土4.444.614.784.61±0.173.01黃綿土9.249.959.649.61±0.403.02塿土12.03±0.24磚紅壤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±0.40九升檢測(cè)江西紅壤10.92±0.24江蘇鹽堿土6.626.536.766.64±0.12山東棕壤16.95±1.925.05砂黃土6.377.378.017.25±0.889.31黑壚土8.808.338.568.56±0.242.24褐土10.80±0.413.03風(fēng)沙土4.093.924.604.20±0.406.87黃綿土6.926.906.906.91±0.01塿土0.89磚紅壤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樣品名稱結(jié)果1結(jié)果2結(jié)果3平均值RSD江西紅壤10.98±0.040.22江蘇鹽堿土6.656.636.706.66±0.040.44山東棕壤18.29±0.40砂黃土7.767.888.207.94±0.262.33黑壚土8.678.778.848.76±0.090.79褐土12.83±0.080.43風(fēng)沙土4.604.554.954.70±0.253.74黃綿土7.597.727.617.64±0.080.74塿土11.32±0.010.02磚紅壤7.907.787.677.78±0.12紫色土22.5422.8722.9822.80±0.260.