Analysis of Organic Additives

50 pL sample (1 2500 diluted) peaks (1) sodium, (2) ammonium, and (3) potassium. 

2 mmol/L TMAOH (pH 12 with NaOH) - acetonitrile (95 5 v/v) flow rate 1 mL/min detection suppressed conductivity injection 50 pL sample (1 50 diluted) peaks (1) chloride and sulfate, (2) saccharin. 

Apart from saccharin and sodium laurylsulfate, thiourea derivatives such as 2-imidazohdinthione and hf, N -diphenylthiourea are also of great importance. They are employed, for example, in electroless nickel and nickelborohydride plating baths as brighteners. 

5 mmol/L H2SO4 — acetone (85 15 v/v) flow rate 0.5 mL/min detection non-suppressed conductivity injection 100 pL sample (1 1000 diluted) sample preparation treatment with cation exchanger in the H form solute concentrations 4.2 g/L citric acid (1) and 0.64 g/L saccharin (2) (taken from [177]). 

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For the analysis of organic additives in polymeric materials, in most cases, prior extraction will be necessary. Depending on the nature of the additive, many different approaches are employed. These include soxhlet extraction with organic solvent or aqueous media, total sample dissolution followed by selective precipitation of the polymer leaving the additive in solution, assisted extraction using pressurised systems, ultrasonic agitation and the use of supercritical fluids. In trace analysis, solid phase extraction (SPME) from solution or solvent partition may be required to increase the analyte concentration. 

Gas chromatographic methods are used for the analysis of organic additives extracted from polymers with solvents and other liquid media or evolved by heating. 

Vit et al. [17] have reported a method for direct quantitative analysis of organic additives in very small PE samples using methane CIMS the conditions needed for accurate and reproducible analytical results were given. Also a variety of additives in 1-2 mg PP samples were analysed qualitatively and quantitatively by means of CIMS [216]. Shortterm reproducibility of peak areas of 6%, and sensitivity corresponding to 0.05% of Cyasorb UV531 in 0.3 mg samples were stated. 

It has been shown that microwave-assisted extraction for the systematic analysis of organic additives in polyolefins can be done by... 

Two organic additives were used that had quite different composition and vulnerability to decomposition under ion irradiation in polystyrene. This enabled the extraction of a principal component related to their content that is independent of the decomposition. It proved the effectiveness of the approach in quantitative analysis of organic additives content in polymers without loss in accuracy due to spectral degradation. 

Ref Quantitative analysis of organic additive content in a polymer by ToF-SIMS with PCA H. Ito, T. Kono. Appl Surf Sci. 2008 255 1044-1047. 

Okumoto [89] has reported an analytical scheme (Scheme 2.8) for automotive rubber products (ENB-EPDM vulcanisates). For high-resolution PyGC analysis, organic additives are first removed from the rubber/(CB, inorganics) formulation. Carbon-black and inorganic material hardly interfere with pyrolysis. For the analysis of the additives the extracted soluble... 

In a study on the identification of organic additives in rubber vulcanisates using mass spectrometry, Lattimer et al. [22] used direct thermal desorption with three different ionisation methods El, Cl and FI. Also, rubber extracts were examinated directly by four ionisation methods (El, Cl, FD and FAB). The authors did not report a clear advantage for direct analysis as compared to analysis after extraction. Direct analysis was a little faster, but the extraction methods were considered to be more versatile. 

FAB-MS has been used for the analysis of lubricant additives, thermally labile or involatile organic compounds, such as macromolecules and dyes, and inorganic compounds. Cationic dyes and dye intermediates, which are typically acid salts, readily yield preformed ions in the FAB matrix solution. They are also very difficult to address by other MS ionisation methods due to their involatility. Lay and Chang [85] used positive ion FAB to characterise a mixture of amine and ketimine cross-linking agents for polymer coatings. Bentz et al. 

Thermospray (TSP) is another soft ionisation technique which produces predominantly MH+ or (M — H) ions, together with some fragmentation. TSP is best suited to the analysis of organic compounds of low molecular mass (<1000 Da) that exhibit some polarity. Polymer additive molecules fall in this wide category. 

Polymer/additive analysis greatly benefits from high-resolution mass data, which often leads to unambiguous identification of (known) additives. However, the investment and operating costs of this instrument do not easily justify its (exclusive) use for the purpose of routine polymer/additive analysis. Analysis of organic polymer additives by means of mass spectrometry is aided by the utilisation of precursor ion and second-generation product ion (MS3) scanning experiments [169], A four-sector... 

Principles and Characteristics Mass-spectral analysis methods may be either indirect or direct. Indirect mass-spectral analysis usually requires some pretreatment (normally extraction and separation) of the material, to separate the organic additives from the polymers and inorganic fillers. The mass spectrometer is then used as a detector. Direct mass-spectrometric methods have to compete with separation techniques such as GC, LC and SFC that are more commonly used for quantitative analysis of polymer additives. The principal advantage of direct mass-spectrometric examination of compounded polymers (or their extracts) is speed of analysis. However, quite often more information can be... 

In this chapter, the main analytical techniques and the methods currently employed in industrial and research laboratories for the analysis of important classes of additives are reviewed. The use of both gas chromatographic and liquid chromatographic methods coupled with mass spectrometry features prominently. Such methodology enables the sensitive and specific detection of many types of organic additives in polymeric materials to parts per billion (jig/kg) levels. Much of the development of these methods has been undertaken as part of research into the migration or extraction of species from food-contact and medical materials [5-7], This chapter also includes some discussion on the analysis of residual monomers and solvents. 

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