Cerebrospinal fluid, ions

The liquid chromatography - tandem mass spectrometry (LC/MS/MS) technique was proposed for the determination of corticosteroids in plasma and cerebrospinal fluid (CSF, liquor) of children with leucosis. Preliminai y sample prepai ation included the sedimentation of proteins, spinning and solid-phase extraction. MS detection was performed by scanning selected ions, with three chai acteristic ions for every corticosteroids. The limit of detection was found 80 pg/ml of plasma. 

Serum and cerebrospinal fluid 206Pb addition and sample acid digestion lead isolation by ion-exchange, elution, and deposition onto platinum wire IDMS No data 80-120 Manton and Cook 1984... 

The central chemoreceptors are located near the ventral surface of the medulla in close proximity to the respiratory center. These receptors are surrounded by the extracellular fluid (ECF) of the brain and respond to changes in H+ ion concentration. The composition of the ECF surrounding the central chemoreceptors is determined by the cerebrospinal fluid (CSF), local blood flow, and local metabolism. 

M. Ramstrom, I. Ivonin, A. Johansson, H. Askmark, K. E. Markides, R. Zubarev, P. Hakansson, S.-M. Aquilonius, and J. Bergquist. Cerebrospinal Fluid Protein Patterns in Neurodegenerative Disease Revealed by Liquid Chromatography Fourier Transform Ion Cyclotron Resonance Mass Spectrometry. Proteomics, 4(2004) 4010-4018. 

Analysis of small ions has been published for many applications other than pharmaceutical applications, and has a growing impact in industrial, environmental, biomedical, clinical, and forensic laboratories. Sample matrices range from simple tap water to Kraft black liquor, including river and seawater, beer and wine, environmental water, and nuclear plant water, but also body fluids such as serum, urine, plasma, cerebrospinal fluid, and many others. Those topics alone would require a separate book. 

Cerebrospinal fluid (liquor cerebrospinalis, CSF) belongs to the class of trans-cellular fluids. It has a low cell count and is hypooncotic and isoosmotic, even with the different composition of ions relative to plasma (lower concentration of Na+, K+, Ca +, inorganic phosphates, and HCO in contrast to a higher concentration of Mg + and CC). The ion composition of CSF is stable changes occur with large plasmatic variations. 

Knuckey NW, Fowler AG, Johanson CE, Nashold JR, Epstein MH (1991) Cisterna magna microdialysis of 22Na to evaluate ion transport and cerebrospinal fluid dynamics. J Neurosurg 74 965-971. 

Eckstein, J.A. et al. Analysis of glutamine, glutamate, pyroglutamate, and GABA in cerebrospinal fluid using ion-pairing HPLC with positive electrospray LC/MS/MS. J. 

The determination of ddl [44] and d4T [45] in human serum was reported by online SPE-LC-MS with positive-ion ESI-MS. 3TC and ddl were applied as IS. The analysis time was less than 5 min for both methods. The LOQ was 10 ng/ml for both compounds. Another group described the determination of ddl and d4T in human plasma, bronchoalveolar lavage fluid (BALE), alveolar cells, PBMC, seminal plasma, cerebrospinal fluid (CSF), and tonsil tissue [57]. Depending on the matrix, either isocratic or gradient LC was applied after SPE sample pretreatment. Positive-ion ESI-MS in SRM mode was applied. The LOQ for both compounds were 2.0 ng/ml in plasma, 0.5 ng/ml in CSF, 0.4 ng/ml in alveolar cells, BALF, and PBMC, 1 ng/ml in seminal plasma, and 0.01 ng/mg in tonsil tissue. 

Neurosteroids are steroids that are synthesized de novo in the central nervous system (androsterone, dihydrotestosterone, testosterone, allopregnanolone, isopregnanolone, and pregananole). After extraction of plasma and cerebrospinal fluids, using solid-phase extraction (SPE), and derivatization with carboxymethoxime, pentafluoro-benzyl, and trimethylsilyl, the derivatized samples were injected into a GC-MS system for quantitative evaluation with a selected ion monitoring (SIM) method. Details of the method have been described in Ref. [25]. 

Approximately 10-11 al of the sample or specimen to be assayed (serum or plasma, and for some chemistries urine or cerebrospinal fluid) are applied to the reagent carrier slide. The specimen will diffuse into the slide within a short time, where it reacts with a reagent that is present in a gelatine or agarose matrix. The dye that forms can be measured reflectometrically. The electrolytes (sodium, potassium, chloride and carbon dioxide) are assayed by means of single use ion-selective electrodes. 

Kwarts E, Kwarts J, Rutgers H. A simple paired-ion liquid chromatography assay for serotonin in cerebrospinal fluid, platelet-rich plasma, serum and urine. Ann Clin Biochem 1984 21 (Pt 5) 425-9. 

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