A standard addition method to quantify serum lithium by inductively coupled plasma mass spectrometry

2021 ◽  
pp. 000456322110547
Author(s):  
Xiaoyu Fan ◽  
Qing Li ◽  
Ping Lin ◽  
Zhonggan Jin ◽  
Meizi Chen ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Inductively Coupled Plasma ◽  
Standard Addition ◽  
Standard Addition Method ◽  
Standard Reference Materials ◽  
Addition Method ◽  
Serum Samples ◽  
Inductively Coupled ◽  
Target Values ◽  
Plasma Mass Spectrometry

Background Therapeutic monitoring of lithium (Li) is important because of its narrow therapeutic range and therapeutic index. Here, the authors present the evaluation of an accurate method for the determination of lithium in serum. Method Serum samples were diluted with 0.3% ultrapure nitric acid and were spiked with an internal standard germanium (Ge). The Li/Ge ratio was detected in He mode; we utilized standard addition method to quantify lithium in human serum. The new inductively coupled plasma mass spectrometry (ICP-MS) assay was characterized for linearity, specificity, imprecision, trueness, accuracy, and comparison. Results The correlation coefficients (r) of linearity were all > 0.9999. The specificity proved to be good. The total coefficients of variation (CV) were 1.11% and 0.49% for the two serum samples. The mean bias from target values of standard reference materials (SRM 956d) was −0.71% for Level I, −017% for Level II, and 2.20 for Level III. External Quality Assessment Scheme for Reference Laboratories in Laboratory Medicine (RELA) gave satisfied results for the new method. Comparison with the ion-selective electrode routine method got reasonable results. Conclusion This high accuracy method is an attractive alternative for lithium measurement and can be used as a candidate reference method to improve quality of serum lithium in China.

DETERMINATION OF 226RA IN URINE USING TRIPLE QUADRUPOLE INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY

2020 ◽  
Vol 191 (4) ◽  
pp. 391-399
Author(s):  
Ge Xiao ◽  
Yongzhong Liu ◽  
Robert L Jones
Keyword(s):  
Mass Spectrometry ◽  
Inductively Coupled Plasma ◽  
Limit Of Detection ◽  
Clinical Decision ◽  
Standard Reference Materials ◽  
Triple Quadrupole ◽  
Inductively Coupled ◽  
Target Values ◽  
Plasma Mass Spectrometry

Abstract Measuring 226Ra in urine at low levels is critical for both biomonitoring and radiological emergency response. Here we report a new analytical method to quantify 226Ra, as developed and validated by a simple dilute-and-shoot procedure, followed by Inductively Coupled Plasma-triple quadrupole-mass spectrometry detection using ‘No Gas MS-MS’ mode. The method provides rapid and accurate results for 226Ra with a limit of detection (LOD) down to 0.007 ng/l (0.26 Bq/l). This LOD is well below the recommended action levels for 226Ra detection in children and pregnant women (C/P) set by the Clinical Decision Guide (NCRP Report #161). Results for 226Ra obtained by this method are within ±7.0% of the target values of standard reference materials spiked in the urine.

Determination of Total Iodine in Infant Formula and Nutritional Products by Inductively Coupled Plasma/Mass Spectrometry: Single-Laboratory Validation

2012 ◽  
Vol 95 (1) ◽  
pp. 169-176 ◽  
Author(s):  
Lawrence H Pacquette ◽  
Alan M Levenson ◽  
Joseph J Thompson
Keyword(s):  
Mass Spectrometry ◽  
Infant Formula ◽  
Inductively Coupled Plasma ◽  
Control Sample ◽  
Microwave Oven ◽  
Standard Reference Materials ◽  
Total Iodine ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry ◽  
Single Laboratory

Abstract A single-laboratory validation by inductively coupled plasma-mass spectrometry was developed for the determination total iodine (m/z 127) in infant formula and adult nutritional products. All samples were digested in nitric acid using a closed vessel microwave oven system; Te (m/z 130) was used as an internal standard. To prevent loss of iodine, ammonium hydroxide solution was added to the samples immediately after digestion. The method quantitation limit for total iodine was 0.3 ng/mL, but a practical LOQ was used at 1.0 ng/mL, a concentration at which there was a negligible bias due to nonlinearity. The total iodine concentrations (112–1900 ng/g) in 14 out of 15 nutritional products were within specification limits. Within-day and day-to-day (6 independent days) precision values were <10% RSD. The observed precision for the overall mean (18 independent days) of a control sample was approximately 4% RSD. In two National Institute of Standards and Technology standard reference materials, total iodine results were within certified limits. Sample spike recoveries for all 15 nutritional products were 92–105%. The data show that a conventional microwave oven digestion procedure can be used to prepare samples for iodine determination. Therefore, this technique is very compatible with other methods being proposed as modern official methods for the analysis of minerals in nutritional products.

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