Aplicações

Fluoride is commonly used in dental products to help prevent tooth decay. When fluoride is present in high concentrations, these products are regulated by 21 CFR 355. Three fluoride compounds used in over the counter (OTC) anti‐cavity dental products are sodium fluoride, stannous fluoride and sodium monofluorophosphate (MFP). The assay of fluoride in these active ingredients and finished formulations are determined by manual titration, or by ion‐selective electrodes. As a part of USP’s global monograph modernization initiative, an alternative selective and sensitive method has been developed and validated – ion chromatography (IC). The proposed IC method can also be used for the identification test as an alternative to the wet chemistry method.

A high throughput automated system was developed to determine pH of culture media using a pH module equipped with an external flow cell. A custom septum-piercing, vented needle was developed to accommodate the shape and size of the customer sample vials. For this application, both accurate and precise pH measurements were required. The data presented in this document was collected by a customer as a part of their validation process and was provided for use with their consent.

LC-MS/MS quantification methods are commonly used to determine trace levels of organic compounds. However, highly polar reversed phases (RPs) lack sufficient retention for very polar compounds, or they fail for charged organics. Separation using ion chromatography (IC) and subsequent MS/MS detection is an innovative alternative approach that combines the fast elution and flexibility of the IC system with the excellent resolution and high sensitivity of the MS/MS detector. This poster presents a fast, robust and reliable IC-MS/MS method for the detection of HAAs and other ionic analytes using the high-end MS/MS system QTRAP 6500+ from SCIEX coupled to a the 940 Professional IC Vario One SeS/PP/HPG instrument. This analytical setup is able to identify and quantify the presence of HAAs at trace levels with LLODs between 0.02 μg/mL and 0.2 μg/L on a single HAA. This capability easily fulfills the sensitivity requirements specified in EU Drinking Water Directive, which specifies a maximum residue level (MRL) of 60 mg/mL for the sum of monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid and dibromoacetic acid present in the representative sample.

An automatic titration method is described using biamperometric endpoint indication for the determination of antimony in antimony-alloyed cable lead (approx. 1% Sb). A 0.01 mol/L KBrO3 solution is used as the titrant.

O zinco, como aquele que ocorre como constituinte de ligas leves, pode ser determinado por titulação de precipitação com indicação de ponto final potenciométrico. A determinação de zinco na presença de cádmio também é possível. 2K4[Fe(CN)6] + 3 ZnCl2 → K2Zn3[Fe(CN)6]2 + 6KCl

A potentiometric method for the determination of nickel in gold and silver electroplating baths is described. The titration is carried out with KCN. Gold and silver are removed before titration by a reduction process. It is also possible to determine nickel in steel alloys, etc. (see the literature reference). Ni2+ + 4 KCN + 2NH4+ → (NH4)2[Ni(CN)4] + 4 K+

A routine method for the determination of copper is described. After dissolving the sample and adding a KI/KCNS solution, the released iodine is back-titrated with thiosulfate. The endpoint indication is potentiometric.

A method for the potentiometric determination of CaCO3 in cement raw meal is described, in which the accurately weighed-out sample is treated with HCl, heated to boiling and the excess HCl is then back-titrated with NaOH.

Este Boletim descreve a determinação simultânea de ouro e cobre por titulação potenciométrica utilizando uma solução de Fe(II) como titulante. O Fe(II) reduz o Au(III) diretamente ao metal livre, enquanto o Cu(II) não reage. Pela adição de íons fluoreto, o Fe(III) é complexado e uma mudança no potencial redox é efetuada. Em seguida, adiciona-se iodeto de potássio, reduzindo assim o Cu(II) a Cu(I), e o iodo livre é novamente titulado com a solução de Fe(II) utilizando um Pt Titrode. Reações químicas: Au(III) + 3Fe(II) → Au + 3Fe(III) 2 Cu(II) + 2 I- → 2 Cu(I) + I2 EU2 + 2Fe(II) → 2 eu- + 2Fe(III)

Ag electrodes are used for the indication of the potentiometric endpoints in precipitation titrations between silver and halide or sulfide ions. A coating on the silver ring may increase the sensitivity of the electrode and can thus reduce the limit of detection. This is why a variety of coated Ag electrodes are commercially available. This bulletin describes how the silver ring of Ag electrodes can be coated with AgCl, AgBr, AgI or Ag2S by electrolysis.