劉宏偉等

摘 要 建立了電感耦合等離子體質(zhì)譜（ICPMS）法直接測(cè)定六氟磷酸鋰中26種雜質(zhì)元素（Be， Na， Mg， Al， K， Ca， Ti， V， Cr， Mn， Fe， Co， Ni， Cu， Zn， Ga， Sr， Zr， Mo， Pd， Ag， Cd， Sn， Sb， Ba， Pb）的分析方法。樣品用無水乙醇溶解后直接用ICPMS測(cè)定。通過在等離子體中引入氧氣，避免樣品溶液中高濃度碳冷凝沉積在質(zhì)譜錐接口和離子透鏡上導(dǎo)致分析元素靈敏度的降低的現(xiàn)象，采用碰撞/反應(yīng)池（CRC）技術(shù)校正了多原子離子質(zhì)譜干擾，選擇基體匹配法校正了基本效應(yīng)。結(jié)果表明，26種雜質(zhì)元素定量標(biāo)準(zhǔn)曲線的線性相關(guān)系數(shù)不小于0.9995，檢出限在0.6～31.9 ng/L之間，RSD為2.5%～7.3%，加標(biāo)回收率在90.6%～108.6%之間。本方法能滿足六氟磷酸鋰中雜質(zhì)元素的分析要求。

關(guān)鍵詞 電感耦合等離子體質(zhì)譜法； 六氟磷酸鋰； 無水乙醇； 碰撞/反應(yīng)池； 雜質(zhì)元素

1 引 言

鋰離子電池電解質(zhì)在電池中起著正負(fù)極之間電荷傳輸?shù)淖饔茫怯绊戨姵毓ぷ鳒囟?、比能量、循環(huán)效率以及安全性能的關(guān)鍵原材料之一，主要由電解質(zhì)鋰鹽、混合有機(jī)溶劑和添加劑組成。由于鋰離子電池的電壓較高且電池負(fù)極材料較為活潑，需采用非水電解質(zhì)。非水電解質(zhì)六氟磷酸鋰（LiPF6）在有機(jī)碳酸酯類溶劑中具有溶解度較大、電導(dǎo)率高、電化學(xué)穩(wěn)定性好等特點(diǎn)，是鋰電池電解質(zhì)的重要組成部分[1]，其雜質(zhì)元素嚴(yán)重影響鋰離子電池的電化學(xué)性能。

目前，LiPF6中雜質(zhì)元素的分析主要采用電感耦合等離子體發(fā)射光譜

3 結(jié)果與討論

3.1 儀器信號(hào)的穩(wěn)定性

LiPF6樣品中雜質(zhì)元素含量低，有機(jī)質(zhì)含量很高，采用無水乙醇稀釋， 進(jìn)一步加大了有機(jī)質(zhì)的濃度，在實(shí)驗(yàn)過程中會(huì)造成炬管、錐口和離子透鏡上積碳，影響分析信號(hào)的穩(wěn)定性。本實(shí)驗(yàn)采用附加的質(zhì)量流速控制器將氧氣加入至等離子體中，通過向輔助氣流中混入氧氣，使高碳有機(jī)物與氧氣燃燒，以消除碳冷凝沉積在接口和離子透鏡上。考察了氬氣中氧氣混入量分別為References

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Direct Determination of Impurity Elements in High Purity

Lithium Hexafluorophosphate Dissolved with Ethyl Alcohol

by Inductively Coupled Plasma Mass Spectrometry

LIU HongWei*， ZHANG Ping， HU HanXiang

（College of Material and Chemical Engineering， Hunan Institute of Technology， Hengyang 421002， China）

Abstract An inductively coupled plasma mass spectrometry （ICPMS） was developed for the direct determination of Be， Na， Mg， Al， K， Ca， Ti， V， Cr， Mn， Fe， Co， Ni， Cu， Zn， Ga， Zr， Mo， Sr， Cd， Ba， Pd， Ag， Sn， Au and Pb in lithium hexafluorophosphate. The sample was dissolved with absolute ethyl alcohol to analyze the above 26 impurity elements in the solution by ICPMS. The condensation and deposition of high concentrations of carbon in mass cone interface and ion lens， which will decrease the sensitivity of element analysis， can be avoided effectively by introducing O2 to plasma. The mass spectral interferences of polyatomic ions to analytes were corrected by collision reaction cell （CRC）. The matrix matching method was used to corrected matrix effect. Satisfactory linearity of each working curve of 26 impurity elements was obtained. The correlation coefficients being over 0.9995， the detection limits for the investigated elements were in the range of 0.6-32 ng/L， the relative standard deviation of each element within 2.5%-7.3%， and the recovery of each element at 90.6%-108.6%. The method had been applied to the determination of trace elements in lithium hexafluorophosphate with satisfactory results.

Keywords Inductively coupled plasma mass spectrometry； Lithium hexafluorophosphate； Absolute ethyl alcohol； Collision reaction cell； Impurity elements

（Received 18 February 2014； accepted 23 March 2014）

by Inductively Coupled Plasma Mass Spectrometry

LIU HongWei*， ZHANG Ping， HU HanXiang

（College of Material and Chemical Engineering， Hunan Institute of Technology， Hengyang 421002， China）

Abstract An inductively coupled plasma mass spectrometry （ICPMS） was developed for the direct determination of Be， Na， Mg， Al， K， Ca， Ti， V， Cr， Mn， Fe， Co， Ni， Cu， Zn， Ga， Zr， Mo， Sr， Cd， Ba， Pd， Ag， Sn， Au and Pb in lithium hexafluorophosphate. The sample was dissolved with absolute ethyl alcohol to analyze the above 26 impurity elements in the solution by ICPMS. The condensation and deposition of high concentrations of carbon in mass cone interface and ion lens， which will decrease the sensitivity of element analysis， can be avoided effectively by introducing O2 to plasma. The mass spectral interferences of polyatomic ions to analytes were corrected by collision reaction cell （CRC）. The matrix matching method was used to corrected matrix effect. Satisfactory linearity of each working curve of 26 impurity elements was obtained. The correlation coefficients being over 0.9995， the detection limits for the investigated elements were in the range of 0.6-32 ng/L， the relative standard deviation of each element within 2.5%-7.3%， and the recovery of each element at 90.6%-108.6%. The method had been applied to the determination of trace elements in lithium hexafluorophosphate with satisfactory results.

Keywords Inductively coupled plasma mass spectrometry； Lithium hexafluorophosphate； Absolute ethyl alcohol； Collision reaction cell； Impurity elements

（Received 18 February 2014； accepted 23 March 2014）

by Inductively Coupled Plasma Mass Spectrometry

LIU HongWei*， ZHANG Ping， HU HanXiang

（College of Material and Chemical Engineering， Hunan Institute of Technology， Hengyang 421002， China）

Abstract An inductively coupled plasma mass spectrometry （ICPMS） was developed for the direct determination of Be， Na， Mg， Al， K， Ca， Ti， V， Cr， Mn， Fe， Co， Ni， Cu， Zn， Ga， Zr， Mo， Sr， Cd， Ba， Pd， Ag， Sn， Au and Pb in lithium hexafluorophosphate. The sample was dissolved with absolute ethyl alcohol to analyze the above 26 impurity elements in the solution by ICPMS. The condensation and deposition of high concentrations of carbon in mass cone interface and ion lens， which will decrease the sensitivity of element analysis， can be avoided effectively by introducing O2 to plasma. The mass spectral interferences of polyatomic ions to analytes were corrected by collision reaction cell （CRC）. The matrix matching method was used to corrected matrix effect. Satisfactory linearity of each working curve of 26 impurity elements was obtained. The correlation coefficients being over 0.9995， the detection limits for the investigated elements were in the range of 0.6-32 ng/L， the relative standard deviation of each element within 2.5%-7.3%， and the recovery of each element at 90.6%-108.6%. The method had been applied to the determination of trace elements in lithium hexafluorophosphate with satisfactory results.

Keywords Inductively coupled plasma mass spectrometry； Lithium hexafluorophosphate； Absolute ethyl alcohol； Collision reaction cell； Impurity elements

（Received 18 February 2014； accepted 23 March 2014）