Structural Elucidation of Agrochemicals and Related Derivatives Using Infrared Ion Spectroscopy

[Image: see text] Agrochemicals frequently undergo various chemical and metabolic transformation reactions in the environment that often result in a wide range of derivates that must be comprehensively characterized to understand their toxicity profiles and their persistence and outcome in the environment. In the development phase, this typically involves a major effort in qualitatively identifying the correct chemical isomer(s) of these derivatives from the many isomers that could potentially be formed. Liquid chromatography-mass spectrometry and nuclear magnetic resonance (NMR) spectroscopy are often used in attempts to characterize such environment transformation products. However, challenges in confidently correlating chemical structures to detected compounds in mass spectrometry data and sensitivity/selectivity limitations of NMR frequently lead to bottlenecks in identification. In this study, we use an alternative approach, infrared ion spectroscopy, to demonstrate the identification of hydroxylated derivatives of two plant protection compounds (azoxystrobin and benzovindiflupyr) contained at low levels in tomato and spinach matrices. Infrared ion spectroscopy is an orthogonal tandem mass spectrometry technique that combines the sensitivity and selectivity of mass spectrometry with structural information obtained by infrared spectroscopy. Furthermore, IR spectra can be computationally predicted for candidate molecular structures, enabling the tentative identification of agrochemical derivatives and other unknowns in the environment without using physical reference standards

Lymph Node Metastasis in Intermediate-Risk Penile Squamous Cell Cancer: A Two-Centre Experience

Background: The risk of lymph node (LN) metastasis in G2T1 penile cancer has been previously reported as 0-50% and is classified as "intermediate" in the European Association of Urology (EAU) guidelines. The management of impalpable regional nodes in this cohort of patients remains contentious and varies among treatment centres depending on tumour factors and local resources. Objectives: To establish the risk of LN metastasis in G2T1 disease. Design, settings, and participants: We interrogated the databases of two referral centres for penile cancer. Measurements: Out of 902 patients, 117 (13%) patients were identified with G2T1 cancers. Those with palpable inguinal nodes (cN1) underwent early inguinal LN dissection (iLND). Those with clinically node negative (cN0) inguinal basins were either observed or surgically staged with iLND or by dynamic sentinel LN biopsy (DSLNB). Median follow-up was 44 mo, with minimum follow-up of 6 mo. Results and limitations: Fifteen of 117 (13%) patients with G2T1 cancer had LN metastasis at initial staging or during follow-up. Six of 12 (50%) cN1 patients had histologically proven LN metastasis on iLND. One hundred five patients were cN0 at presentation. Ten cN0 patients had prophylactic iLND, none of which yielded LN metastasis; 5 of 64 (8%) cN0 patients who had DSLNB had tumour-positive LNs, and 4 of 31 (13%) cN0 patients who were observed developed LN metastasis during follow-up. In cN0 patients, the risk of LN metastasis at initial staging or during surveillance was 9%. Conclusions: We consider that in cN0 patients with G2T1 penile cancer, the risk of developing metastases during surveillance warrants surgical and potentially curative staging. However, the morbidity of prophylactic bilateral iLND is too great to justify a detection rate of 9%. Less morbid alternatives such as DSLNB are advisable in G2T1 disease. (C) 2009 European Association of Urology. Published by Elsevier B. V. All rights reserved.Prostatic carcinom