In this contribution, the utility of sequential injection analysis in combination with surface-enhanced Raman spectroscopy (SERS) as a detection technique was investigated for simultaneous determination of aspirin and vitamin C in their pharmaceutical dosage forms and in spiked urine samples. The silver substrate was synthesized in situ by laser-induced photochemical procedure. By focusing the laser on a flow cell at 1 ml/min of continuous flow of 0.5 mM silver nitrate and 5 mM sodium citrate mixture, an active silver spot on the inner wall of the flow cell was prepared in a few seconds. The whole setup is fully computer controlled using ATLAS software to combine the two techniques. The system allows sequential determination of aspirin concentrations ranging from 100 to 500 ng/ml and vitamin C concentrations between 10 and 110 ng/ml with good precision of relative standard deviations (RSDs) of 0.85 and 1.7 %, respectively. A comparison of these results with those of the reported procedures showed excellent results compared with t and F values, indicating good accuracy and precision. The detection limits were 32 and 3 ng/ml for aspirin and vitamin C, respectively.

In this contribution, the utility of sequential injection analysis in combination with surface-enhanced Raman spectroscopy (SERS) as a detection technique was investigated for simultaneous determination of aspirin and vitamin C in their pharmaceutical dosage forms and in spiked urine samples. The silver substrate was synthesized in situ by laser-induced photochemical procedure. By focusing the laser on a flow cell at 1 ml/min of continuous flow of 0.5 mM silver nitrate and 5 mM sodium citrate mixture, an active silver spot on the inner wall of the flow cell was prepared in a few seconds. The whole setup is fully computer controlled using ATLAS software to combine the two techniques. The system allows sequential determination of aspirin concentrations ranging from 100 to 500 ng/ml and vitamin C concentrations between 10 and 110 ng/ml with good precision of relative standard deviations (RSDs) of 0.85 and 1.7 %, respectively. A comparison of these results with those of the reported procedures showed excellent results compared with t and F values, indicating good accuracy and precision. The detection limits were 32 and 3 ng/ml for aspirin and vitamin C, respectively.

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Elucidation and quantitative determination of some of commonly used penicillins (ampicillin, penicillin G and carbenicillin) in the presence of their main degradation product (penicilloic acid) were developed. Forced acidic and basic degradation processes were applied at different time intervals. The formed degradation products were elucidated and quantified using surface enhanced Raman spectroscopy (SERS). Silver nanoparticles (AgNPs) prepared by reduction of silver nitrate using hydroxylamine-HCl in alkaline medium were used as SERS substrate. The results obtained in SERS were confirmed by the application of LC/MS method. The concentration range was 100-600 ng/ml in case of the studied penicillins and 100-700 ng/ml in case of penicilloic acid. An excellent correlation coefficient was found in case of ampicillin (r= 0.9993) and in the case of penicilloic acid (r= 0.9997). Validation procedures were carried out including precision, robustness and accuracy by comparing F- and t-values of both the proposed and reported methods.

Elucidation and quantitative determination of some of commonly used penicillins (ampicillin, penicillin G and carbenicillin) in the presence of their main degradation product (penicilloic acid) were developed. Forced acidic and basic degradation processes were applied at different time intervals. The formed degradation products were elucidated and quantified using surface enhanced Raman spectroscopy (SERS). Silver nanoparticles (AgNPs) prepared by reduction of silver nitrate using hydroxylamine-HCl in alkaline medium were used as SERS substrate. The results obtained in SERS were confirmed by the application of LC/MS method. The concentration range was 100-600 ng/ml in case of the studied penicillins and 100-700 ng/ml in case of penicilloic acid. An excellent correlation coefficient was found in case of ampicillin (r= 0.9993) and in the case of penicilloic acid (r= 0.9997). Validation procedures were carried out including precision, robustness and accuracy by comparing F- and t-values of both the proposed and reported methods.

Elucidation and quantitative determination of some of commonly used penicillins (ampicillin, penicillin G and carbenicillin) in the presence of their main degradation product (penicilloic acid) were developed. Forced acidic and basic degradation processes were applied at different time intervals. The formed degradation products were elucidated and quantified using surface enhanced Raman spectroscopy (SERS). Silver nanoparticles (AgNPs) prepared by reduction of silver nitrate using hydroxylamine-HCl in alkaline medium were used as SERS substrate. The results obtained in SERS were confirmed by the application of LC/MS method. The concentration range was 100-600 ng/ml in case of the studied penicillins and 100-700 ng/ml in case of penicilloic acid. An excellent correlation coefficient was found in case of ampicillin (r= 0.9993) and in the case of penicilloic acid (r= 0.9997). Validation procedures were carried out including precision, robustness and accuracy by comparing F- and t-values of both the proposed and reported methods.

Biothiols play an essential role in a number of biological processes in living organisms including detoxification and metabolism. Fetal to neonatal transition poses a pro-oxidant threat for newborn infants, especially those born prematurely. A reliable and rapid tool for the direct determination of thiols in small volume whole blood (WB) samples would be desirable for its application in clinical practice. This study shows the feasibility of Surface Enhanced Raman Spectroscopy (SERS) using a silver colloid prepared by reduction of silver nitrate using hydroxylamine, as the SERS substrate for the quantification of thiols in WB samples after a simple precipitation step for protein removal. Bands originating from biothiols (790, 714 and 642 cm−1) were enhanced by the employed SERS substrate and the specificity of the detected SERS signal was tested for molecules presenting –SH functional groups. A statistically significant correlation between the obtained SERS signals and the thiol concentration measured using a chromatographic reference method in umbilical cord WB samples could be demonstrated. Using WB GSH concentrations obtained from the chromatographic reference procedure, a Partial Least Squares (PLS) regression model covering GSH concentrations from 13 to 2200 μM was calculated obtaining a root mean square error of prediction (RMSEP) of 381 μM when applied to an external test set. The developed approach uses small blood sample volumes (50 μL), which is important for clinical applications, especially in the field of neonatology. This feasibility study shows that the present approach combines all the necessary characteristics for its potential application in clinical practice.

A simple, fast and sensitive surface enhanced Raman spectroscopy (SERS) method for quantitative determination of fluoroquinolone antibiotic Ofloxacin (OFX) is presented. Also the stability behavior of OFX was investigated by monitoring the SERS spectra of OFX after various degradation processes. Acidic, basic and oxidative force degradation processes were applied at different time intervals. The forced degradation conditions were conducted and followed using SERS method utilizing silver nanoparticles (Ag NPs) as a SERS substrate. The Ag NPs colloids were prepared by reduction of silver nitrate using polyethyelene glycol (PEG) as a reducing and stabilizing agent. Validation tests were done in accordance with International Conference on Harmonization (ICH) guidelines. The calibration curve with a correlation coefficient (R = 0.9992) was constructed as a relationship between the concentration range of OFX (100–500 ng/ml) and SERS intensity at 1394 cm−1 band. LOD and LOQ values were calculated and found to be 23.5 ng/ml and 72.6 ng/ml, respectively. The developed method was applied successfully for quantitation of OFX in different pharmaceutical dosage forms. Kinetic parameters were calculated including rate constant of the degradation of the studied antibiotic.