Measurement uncertainty and risk of false conformity decision in the performance evaluation of liquid chromatography analytical procedures.

Liquid chromatography is one of the main techniques used in pharmaceutical quality control analytical procedures. However, there will always be a measurement uncertainty (MU) associated with them, that can lead to the approval of an out of specification lot (consumer risk) or rejection of a lot within specification (producer risk). Thus, the aim of this study was to evaluate the performance of liquid chromatography analytical procedures based on their measurement uncertainty and to estimate the risk of false conformity decisions. The uncertainties of the analytical procedures were estimated based on the results of validation (trueness and precision). Then, the ratio between overall uncertainty and specification range (U/T%) was calculated. It was noted that in most cases (73%), random errors (precision) contributes more significantly to the overall uncertainty when compared to systematic errors (trueness). Monte Carlo method was used, generating different manufacturing processes scenarios, and analytical results based on the MU of each analytical procedure. Then, consumer's and producer's risks were estimated from the simulated values. Pharmaceutical dosage forms that require more steps in sample preparation had higher measurement uncertainties, often above the recommended target uncertainty. As most of the analytical procedures showed U/T% values above recommended, the majority presented high estimated risk values and did not fit for purpose. Therefore, it is important to considerate the measurement uncertainty as part of analytical procedures validation, since trueness and precision values affect directly the measurement uncertainty and the risk of false conformity decisions.

Simple procedure for nutrient analysis of coffee plant with energy dispersive X-ray fluorescence spectrometry (EDXRF)

Nutrient analysis is used to estimate nutrient content of crop plants to manage fertilizer application for sustained crop production. Direct solid analysis of agricultural and environmental samples by energy dispersive X-ray fluorescence spectrometry (EDXRF) was chosen as alternative technique to evaluate the simultaneous multielemental quantification of the most important essential elements in coffee (Coffea arabica L.) plants. Inductively coupled plasma atomic emission spectrometry and certified reference materials made from leaves were used to calibrate and check the trueness of EDXRF method for the determination of the concentration of several nutrients in coffee leaves and branches. Fluorescence spectrometry proved to be advantageous and presented low cost as loose powder samples could be used. Samples collected from a field experiment where coffee plants were treated with excess of Ni and Zn were used to verify the practical application of the method. Good relationships were achieved between certified values and data obtained by EDXRF, with recoveries ranging from 82 to 117 %.

Simple procedure for nutrient analysis of coffee plant with energy dispersive X-ray fluorescence spectrometry (EDXRF)

Nutrient analysis is used to estimate nutrient content of crop plants to manage fertilizer application for sustained crop production. Direct solid analysis of agricultural and environmental samples by energy dispersive X-ray fluorescence spectrometry (EDXRF) was chosen as alternative technique to evaluate the simultaneous multielemental quantification of the most important essential elements in coffee (Coffea arabica L.) plants. Inductively coupled plasma atomic emission spectrometry and certified reference materials made from leaves were used to calibrate and check the trueness of EDXRF method for the determination of the concentration of several nutrients in coffee leaves and branches. Fluorescence spectrometry proved to be advantageous and presented low cost as loose powder samples could be used. Samples collected from a field experiment where coffee plants were treated with excess of Ni and Zn were used to verify the practical application of the method. Good relationships were achieved between certified values and data obtained by EDXRF, with recoveries ranging from 82 to 117 %.