Comparación de métodos de análisis de cannabinoides en orina / A comparison of methods for the analysis of cannabinoids in urine

Se comparan los resultados obtenidos al aplicar los siguientes métodos cualitativos: L.I.A. (inhibición de la aglutinación del láxtex); F.P.I.A. (inmunoensayo de polarización fluorescente); E.I.M.T.-100 (enzimoinmunoensayo); y C.C.F. (cromatografía en capa fina) a la determinación de cannabinoides en cincuenta y tres muestras de orina de pacientes consumidores habituales de cannabis. Considerando un "cut off" de 100 ng/ml se ha encontrado un elevado número de muestras (15-25 por ciento), según la técnica, en las que los resultados se consideran negativos, existiendo la presencia de cannabinoides. Sin embargo, empleando un "cut off" de 20 ng/ml, la totalidad de las muestras fueron positivas. Se encuentra que el límite de detección es para el F.P.I.A (7.5 NG/ML) < C.C.F. (10 NG/ML) < E.M.I.T.-100 (30 ng/ml) < L.I.A. (100 ng/ml), si bien este último es el más sencillo en su manejo. También se observa una correlación positiva altamente significativa (P<0.00001) entre los logaritmos de las concentraciones obtenidas al aplicar F.P.I.A. y E.M.I.T. como semicuantitativos. Los resultados de F.P.I.A. fueron inferiores a los detectados por E.M.I.T., lo cual podría ser debido a una mayor selectividad de la reacción inmunológica correspondiente al primer método. Se ha observado que los niveles de cannabinoides disminuyen con el tiempo transcurrido desde el último consumo, así como con la frecuencia de consumo que manifiestan los pacientes (AU)

Quantity of K, Ca, Na, Mg, Fe, Cu, Pb, Zn and ashes in DOC Tacoronte-Acentejo (Canary Islands, Spain) musts and wines.

This study determines ash, K, Ca, Na, Mg, Fe, Cu, Pb, and Zn content in musts and wines of the DOC Tacoronte-Acentejo (Tenerife, Canary Islands) from two consecutive harvests. Samples were treated with HNO3 and H2O2. Na and K were determined by flame photometry and the remaining metals by air/acetilene flame atomic absorption spectrophotometry. Significant differences were observed in Na, Ca and Mg contents between both harvests, possibly due to climate conditions.

Evaluation of multicomponent fluorimetric analytical data by use of partial least-squares calibration. Application to the determination of codeine and ephedrine in urine.

A partial least-squares calibration (PLS) method for the simultaneous spectrofluorimetric determination of acetylsalicylic acid, codeine and ephedrine is proposed. The use of PLS for the multicomponent spectrofluorimetric determination is demonstrated by analysing synthetic mixtures. Analyte mixtures can be resolved even in the presence of strongly overlapped fluorescence signals. The method was validated by subjecting experimental data to exhaustive statistical analysis. The proposed method was applied to the simultaneous determination of the three drugs in synthetic mixtures with a urine matrix. The concentration ranges considered are 1.56-10.92 and 25-100 micrograms/ml for the codeine-ephedrine mixture, and 0.8-3.2, 0.1-0.5 and 1.6-4.8 micrograms/ml for the acetylsalicylic acid-codeine-ephedrine mixture. The analytical results were quite good in all cases.

Use of an azo derivative immobilized on an anionic resin for the determination of aluminium in water and dialysis fluids.

We studied the retention of aluminium on Chromotrope-2R immobilized on Amberlite IRA-400 resin with a view to the subsequent atomic spectrometric determination of the metal. The determinative method thus developed allows the determination of aluminium in water and dialysis fluids over the concentration ranges 0.92-19.46 and 0.37-0.74 mumol/l, respectively.

Simultaneous determination of imipramine and amitryptiline by derivative spectrophotometry.

Three methods are proposed for the simultaneous determination of imipramine and amitryptiline by derivative spectrophotometry, one of them using both first- and second-derivative spectra, and the others using the first- and second-derivative spectra, respectively, obtained from a "diode array" spectrophotometer. The methods allow the determination of 0.62-10.14 micrograms ml-1 of imipramine, and 0.63-10.04 micrograms ml-1 of amitryptiline, and have been applied to their determination in blood serum.